bluuebunny/crossref_metadata_2025 huggingface dataset:
Technical Note: Prediction Models of Airborne Sound Insulation of Multilayer Materials with Viscoelastic Thin Sheets
Authors: Alba Jesús , Marant Vincent , Aguilera Juan Luis , Ramis Jaime , Del Rey Romina
Published: December 2008

The growing introduction of new insulation materials in building acoustics has caused an increase of the importance of the prediction tools. Appropriate simulations allow strictly necessary laboratory measurements to be identified. In this way, costs are reduced. The demands of new legislation has resulted in the appearance of various software designed to facilitate prediction. The prediction models are based on different hypotheses: adaptation of impedances, spatial behaviour of spectral components, statistical energy distribution, the Finite Element Method (FEM), etc. Each of these models and methods offer advantages and contain limitations. In this paper, different models for prediction of sound insulation of multi-layer systems, are analysed. A method, based on adaptation of impedances is considered, and the results are compared with those obtained from FEM and also from experimental results. Adjustments are proposed to the models, to improve the prediction in certain frequency ranges.
“Modern Teaching” Needs Modern Conditions — Communication Behaviour of Pupils and Teachers in Highly Absorbent Classrooms
Authors: Oberdörster Markus , Tiesler Gerhart
Published: December 2008

This paper investigates the kind of work and communication behaviour in classrooms in two elementary schools. Using a database of 175 examined lessons an analysis is made of how different kinds of work (frontal lessons vs. differentiated lessons) have an effect on the sound level in the classroom. Parameters are discussed, which can describe classroom acoustics appropriately. Also discussed are how altered room characteristics (eg. increased absorption, shortened reverberation time and improved speech intelligibility) affect the sound level in the context of each kind of work. A methodical examination of the database allows an assessment of mean values but also of the detailed teaching phases, as characterised by certain pedagogical factors. The results provide the basis for discussion of stress and work demands of teachers.
On the Propagation of Sound in a High-Speed Non-Isothermal Shear Flow
Authors: Campos L.M.B.C. , Kobayashi M.H.
Published: December 2008

The propagation of sound in shear flows is relevant to the acoustics of wall and duct boundary layers, and to jet shear layers. The acoustic wave equation in a shear flow has been solved exactly only for a plane unidirectional homentropic mean shear flow, in the case of three velocity profiles: linear, exponential and hyperbolic tangent. The assumption of homentropic mean flow restricts application to isothermal shear flows. In the present paper the wave equation in an plane unidirectional shear flow with a linear velocity profile is solved in an isentropic non-homentropic case, which allows for the presence of transverse temperature gradients associated with the ***non-uniform sound speed. The sound speed profile is specified by the condition of constant enthalpy, i.e. homenergetic shear flow. In this case the acoustic wave equation has three singularities at finite distance (besides the point at infinity), viz. the critical layer where the Doppler shifted frequency vanishes, and the critical flow points where the sound speed vanishes. By matching pairs of solutions around the singular and regular points, the amplitude and phase of the acoustic pressure in calculated and plotted for several combinations of wavelength and wave frequency, mean flow vorticity and sound speed, demonstrating, among others, some cases of sound suppression at the critical layer.
The poly(A)-dependent degradation pathway of rpsO mRNA is primarily mediated by RNase R
Authors: Andrade José M. , Hajnsdorf Eliane , Régnier Philippe , Arraiano Cecília M.
Published: December 2008

Polyadenylation is an important factor controlling RNA degradation and RNA quality control mechanisms. In this report we demonstrate for the first time that RNase R has in vivo affinity for polyadenylated RNA and can be a key enzyme involved in poly(A) metabolism. RNase II and PNPase, two major RNA exonucleases present in Escherichia coli, could not account for all the poly(A)-dependent degradation of the rpsO mRNA. RNase II can remove the poly(A) tails but fails to degrade the mRNA as it cannot overcome the RNA termination hairpin, while PNPase plays only a modest role in this degradation. We now demonstrate that in the absence of RNase E, RNase R is the relevant factor in the poly(A)-dependent degradation of the rpsO mRNA. Moreover, we have found that the RNase R inactivation counteracts the extended degradation of this transcript observed in RNase II-deficient cells. Elongated rpsO transcripts harboring increasing poly(A) tails are specifically recognized by RNase R and strongly accumulate in the absence of this exonuclease. The 3′ oligo(A) extension may stimulate the binding of RNase R, allowing the complete degradation of the mRNA, as RNase R is not susceptible to RNA secondary structures. Moreover, this regulation is shown to occur despite the presence of PNPase. Similar results were observed with the rpsT mRNA. This report shows that polyadenylation favors in vivo the RNase R-mediated pathways of RNA degradation.
Team climate, climate strength and team performance. A longitudinal study
Authors: González‐Romá Vicente , Fortes‐Ferreira Lina , Peiró José M.
Published: December 2008

We tested the hypothesis that the relationship between team climate and team performance is moderated by climate strength. The study sample was composed of 155 bank branches, and a two‐wave panel design was implemented. We measured four team climate facets (support, innovation, goal achievement and enabling formalization). We obtained two subjective indicators of team performance (ratings provided by team members and by team managers) and a financial indicator of team performance. Seven out of the 12 interaction effects tested were statistically significant and showed the expected sign. When financial team performance was the criterion, only the interaction term was significant. This suggests that only strong climates are related to financial team performance over time.
Intrinsic need satisfaction and the job attitudes of volunteers versus employees working in a charitable volunteer organization
Authors: Boezeman Edwin J. , Ellemers Naomi
Published: December 2008

This research examines how intrinsic need satisfaction during volunteer work relates to the job attitudes of volunteers (Deci & Ryan, 2000; Ryan & Deci, 2000). We distinguish between autonomy, competence, and relatedness needs, and predict these to have distinct effects on volunteers' job satisfaction and intent to remain with the volunteer organization. We then compare volunteer workers to a matched sample of paid employees (performing identical tasks within the same organization) in the way in which they derive their job satisfaction and intent to remain from satisfaction of these three types of needs. As predicted, path analysis (N=105) shows that satisfaction of autonomy needs and relatedness needs are positively related to the intent to remain a volunteer with the volunteer organization, and this relation is mediated by satisfaction with the volunteer job. The matched samples comparison further reveals that whereas the job satisfaction and intent to remain of paid employees is most clearly predicted by satisfaction of autonomy needs, satisfaction of relatedness needs is the primary predictor of job satisfaction and intent to remain among volunteers. Theoretical and practical implications, as well as avenues for further research, are discussed.
Engine Oil Volatility: Noack Evaporation Methods
Authors: Kishore Nadkarni R. A.
Published: December 2008

The Noack evaporation loss is an important test for base oils and lubricating oils used in internal combustion engines. The alternate test methods used for this determination are described and evaluated regarding their applicability in the field.
Accurate Determination of Surface Heat Fluxes During Quenching Characterized by Boiling Water Heat Transfer
Authors: Wells M. A. , Daun K. J.
Published: December 2008

Mathematical models play a critical role in design, optimization, and control of water quenching treatment in metals processing. Modeling these processes correctly is predicated on accurately characterizing the heat transfer at the product surface throughout the quench operation, usually with a boiling curve. These curves are most often generated from time-resolved subsurface temperature measurements carried out during quenching, although data analysis is complicated by the ill-posed nature of the underlying problem. This paper reviews the best experimental and analytical practices that have been developed for recovering the boiling water curve through an inverse heat conduction analysis.
A Model Selection Approach for the Identification of Quantitative Trait Loci in Experimental Crosses, Allowing Epistasis
Authors: Manichaikul Ani , Moon Jee Young , Sen Śaunak , Yandell Brian S , Broman Karl W
Published: December 2008

The identification of quantitative trait loci (QTL) and their interactions is a crucial step toward the discovery of genes responsible for variation in experimental crosses. The problem is best viewed as one of model selection, and the most important aspect of the problem is the comparison of models of different sizes. We present a penalized likelihood approach, with penalties on QTL and pairwise interactions chosen to control false positive rates. This extends the work of Broman and Speed to allow for pairwise interactions among QTL. A conservative version of our penalized LOD score provides strict control over the rate of extraneous QTL and interactions; a more liberal criterion is more lenient on interactions but seeks to maintain control over the rate of inclusion of false loci. The key advance is that one needs only to specify a target false positive rate rather than a prior on the number of QTL and interactions. We illustrate the use of our model selection criteria as exploratory tools; simulation studies demonstrate reasonable power to detect QTL. Our liberal criterion is comparable in power to two Bayesian approaches.
Multilocus Patterns of Nucleotide Diversity, Population Structure and Linkage Disequilibrium inBoechera stricta, a Wild Relative of Arabidopsis
Authors: Song Bao-Hua , Windsor Aaron J , Schmid Karl J , Ramos-Onsins Sebastian , Schranz M Eric , Heidel Andrew J , Mitchell-Olds Thomas
Published: December 2008

Information about polymorphism, population structure, and linkage disequilibrium (LD) is crucial for association studies of complex trait variation. However, most genomewide studies have focused on model systems, with very few analyses of undisturbed natural populations. Here, we sequenced 86 mapped nuclear loci for a sample of 46 genotypes of Boechera stricta and two individuals of B. holboellii, both wild relatives of Arabidopsis. Isolation by distance was significant across the species range of B. stricta, and three geographic groups were identified by structure analysis, principal coordinates analysis, and distance-based phylogeny analyses. The allele frequency spectrum indicated a genomewide deviation from an equilibrium neutral model, with silent nucleotide diversity averaging 0.004. LD decayed rapidly, declining to background levels in ∼10 kb or less. For tightly linked SNPs separated by <1 kb, LD was dependent on the reference population. LD was lower in the specieswide sample than within populations, suggesting that low levels of LD found in inbreeding species such as B. stricta, Arabidopsis thaliana, and barley may result from broad geographic sampling that spans heterogeneous genetic groups. Finally, analyses also showed that inbreeding B. stricta and A. thaliana have ∼45% higher recombination per kilobase than outcrossing A. lyrata.
Thea2Mating-Type Locus Geneslga2andrga2Direct Uniparental Mitochondrial DNA (mtDNA) Inheritance and Constrain mtDNA Recombination During Sexual Development ofUstilago maydis
Authors: Fedler Michael , Luh Kai-Stephen , Stelter Kathrin , Nieto-Jacobo Fernanda , Basse Christoph W
Published: December 2008

Uniparental inheritance of mitochondria dominates among sexual eukaryotes. However, little is known about the mechanisms and genetic determinants. We have investigated the role of the plant pathogen Ustilago maydis genes lga2 and rga2 in uniparental mitochondrial DNA (mtDNA) inheritance during sexual development. The lga2 and rga2 genes are specific to the a2 mating-type locus and encode small mitochondrial proteins. On the basis of identified sequence polymorphisms due to variable intron numbers in mitochondrial genotypes, we could demonstrate that lga2 and rga2 decisively influence mtDNA inheritance in matings between a1 and a2 strains. Deletion of lga2 favored biparental inheritance and generation of recombinant mtDNA molecules in combinations in which inheritance of mtDNA of the a2 partner dominated. Conversely, deletion of rga2 resulted in predominant loss of a2-specific mtDNA and favored inheritance of the a1 mtDNA. Furthermore, expression of rga2 in the a1 partner protected the associated mtDNA from elimination. Our results indicate that Lga2 in conjunction with Rga2 directs uniparental mtDNA inheritance by mediating loss of the a1-associated mtDNA. This study shows for the first time an interplay of mitochondrial proteins in regulating uniparental mtDNA inheritance.
Mutations in the Chromosomal Passenger Complex and the Condensin Complex Differentially Affect Synaptonemal Complex Disassembly and Metaphase I Configuration in Drosophila Female Meiosis
Authors: Resnick Tamar D , Dej Kimberley J , Xiang Youbin , Hawley R Scott , Ahn Caroline , Orr-Weaver Terry L
Published: December 2008

Production of haploid gametes relies on the specially regulated meiotic cell cycle. Analyses of the role of essential mitotic regulators in meiosis have been hampered by a shortage of appropriate alleles in metazoans. We characterized female-sterile alleles of the condensin complex component dcap-g and used them to define roles for condensin in Drosophila female meiosis. In mitosis, the condensin complex is required for sister-chromatid resolution and contributes to chromosome condensation. In meiosis, we demonstrate a role for dcap-g in disassembly of the synaptonemal complex and for proper retention of the chromosomes in a metaphase I-arrested state. The chromosomal passenger complex also is known to have mitotic roles in chromosome condensation and is required in some systems for localization of the condensin complex. We used the QA26 allele of passenger component incenp to investigate the role of the passenger complex in oocyte meiosis. Strikingly, in incenpQA26 mutants maintenance of the synaptonemal complex is disrupted. In contrast to the dcap-g mutants, the incenp mutation leads to a failure of paired homologous chromosomes to biorient, such that bivalents frequently orient toward only one pole in prometaphase and metaphase I. We show that incenp interacts genetically with ord, suggesting an important functional relationship between them in meiotic chromosome dynamics. The dcap-g and incenp mutations cause maternal effect lethality, with embryos from mutant mothers arrested in the initial mitotic divisions.
Characterization of Demographic Expansions From Pairwise Comparisons of Linked Microsatellite Haplotypes
Authors: Navascués Miguel , Hardy Olivier J , Burgarella Concetta
Published: December 2008

This work extends the methods of demographic inference based on the distribution of pairwise genetic differences between individuals (mismatch distribution) to the case of linked microsatellite data. Population genetics theory describes the distribution of mutations among a sample of genes under different demographic scenarios. However, the actual number of mutations can rarely be deduced from DNA polymorphisms. The inclusion of mutation models in theoretical predictions can improve the performance of statistical methods. We have developed a maximum-pseudolikelihood estimator for the parameters that characterize a demographic expansion for a series of linked loci evolving under a stepwise mutation model. Those loci would correspond to DNA polymorphisms of linked microsatellites (such as those found on the Y chromosome or the chloroplast genome). The proposed method was evaluated with simulated data sets and with a data set of chloroplast microsatellites that showed signal for demographic expansion in a previous study. The results show that inclusion of a mutational model in the analysis improves the estimates of the age of expansion in the case of older expansions.
Nitrogen Catabolite Repression-Sensitive Transcription as a Readout of Tor Pathway Regulation: The Genetic Background, Reporter Gene and GATA Factor Assayed Determine the Outcomes
Authors: Georis Isabelle , Feller André , Tate Jennifer J , Cooper Terrance G , Dubois Evelyne
Published: December 2008

Nitrogen catabolite repression (NCR)-sensitive genes, whose expression is highly repressed when provided with excess nitrogen and derepressed when nitrogen is limited or cells are treated with rapamycin, are routinely used as reporters in mechanistic studies of the Tor signal transduction pathway in Saccharomyces cerevisiae. Two GATA factors, Gln3 and Gat1, are responsible for NCR-sensitive transcription, but recent evidence demonstrates that Tor pathway regulation of NCR-sensitive transcription bifurcates at the level of GATA factor localization. Gln3 requires Sit4 phosphatase for nuclear localization and NCR-sensitive transcription while Gat1 does not. In this article, we demonstrate that the extent to which Sit4 plays a role in NCR-sensitive transcription depends upon whether or not (i) Gzf3, a GATA repressor homologous to Dal80, is active in the genetic background assayed; (ii) Gat1 is able to activate transcription of the assayed gene in the absence of Gln3 in that genetic background; and (iii) the gene chosen as a reporter is able to be transcribed by Gln3 or Gat1 in the absence of the other GATA factor. Together, the data indicate that in the absence of these three pieces of information, overall NCR-sensitive gene transcription data are unreliable as Tor pathway readouts.
Donor Blood Glucose 6-Phosphate Dehydrogenase Deficiency Reduces the Efficacy of Exchange Transfusion in Neonatal Hyperbilirubinemia
Authors: Samanta Sandip , Kumar Praveen , Kishore Sai Sunil , Garewal Gurjeewan , Narang Anil
Published: December 2008

OBJECTIVES. Acute intravascular hemolysis after exchange transfusion with glucose 6-phosphate dehydrogenase–deficient blood has been reported; however, it is not routine to screen donor blood for glucose 6-phosphate dehydrogenase deficiency while performing exchange transfusion. We hypothesized that exchange transfusion with glucose 6-phosphate dehydrogenase–deficient blood would lead to a less-than-expected decrease in total serum bilirubin. The objective of this study was to evaluate the effect of exchange transfusion with glucose 6-phosphate dehydrogenase–deficient blood in neonates with idiopathic hyperbilirubinemia on postexchange total serum bilirubin levels, duration of phototherapy, and need for repeat exchange transfusions.

METHODS. All neonates who were undergoing exchange transfusion for idiopathic hyperbilirubinemia were enrolled. A sample of donor blood was collected at the time of exchange transfusion for a glucose 6-phosphate dehydrogenase assay. The standard criteria for starting and stopping phototherapy and exchange transfusion were applied.

RESULTS. During the 1-year study period, 21 infants underwent exchange with glucose 6-phosphate dehydrogenase–deficient blood, and 114 neonates with similar baseline characteristics underwent exchange transfusion with glucose 6-phosphate dehydrogenase–normal blood. From 6 to 60 hours after exchange transfusion, there was a significantly lesser drop in total serum bilirubin in the recipients of glucose 6-phosphate dehydrogenase–deficient donor blood compared with recipients of glucose 6-phosphate dehydrogenase–normal blood. The mean duration of phototherapy in the postexchange period and number of infants who underwent repeat exchange transfusions were significantly higher in recipients of glucose 6-phosphate dehydrogenase–deficient donor blood in comparison with control subjects. Concurrently, there was a significantly higher drop in hematocrit and rise in plasma hemoglobin in the glucose 6-phosphate dehydrogenase–deficient donor group.

CONCLUSIONS. Exchange transfusion with glucose 6-phosphate dehydrogenase–deficient donor blood leads to a lesser drop in postexchange total serum bilirubin. It prolongs the duration of phototherapy and increases the need for repeat exchange transfusions.
Susceptibility genetic variants in Hungarian morbus Crohn and ulcerative colitis patients
Authors: Magyari Lili , Melegh Béla
Published: December 2008

Gyulladásos bélbetegségekre (Crohn-betegség, colitis ulcerosa) hajlamosító gének vizsgálatát végeztük magyar populációban, ezek a CARD15 gén R702W, G908R, 1007finsC variánsai, az SLC22A4 gén C1672T és az SLC22A5 G-207C variánsai, valamint az általuk meghatározott TC haplotípus, a CTLA4 gén A+49G eltérése és az IL23R gén rs10889677 C/A, rs2201841 T/C, rs1884444 G/T variánsai. Vizsgálataink során 201 felnőtt Crohn-beteg, 241 felnőtt colitis ulcerosás, valamint 19 gyermek Crohn-beteget analizáltunk. Kontrollnak 235 felnőttől és 49 gyermektől vettünk vért. A genotipizálás során PCR/RFLP módszert és direkt szekvenálást alkalmaztunk. Eredményeink alapján kijelenthetjük, hogy a CARD15 gén mutációi közül felnőttekben az 1007finsC, míg gyermekekben az 1007finsC és a G908R variáns is hajlamosít Crohn-betegség kialakulására. Az SLC22A4 és SLC22A5 gének által meghatározott TC haplotípus esetén nem találtunk szignifikáns különbséget a betegcsoportok kontrollokkal való összevetése során. A CTLA4 gén A+49G variánsa nem bizonyult hajlamosító tényezőnek gyulladásos bélbetegségekre. Az IL23R gén esetén az rs10889677 C/A és az rs2201841 T/C jelent kockázati tényezőt Crohn-betegség kialakulására. Megállapíthatjuk, hogy különböző populációktól függ, hogy az adott genetikai variánsok hajlamosítanak-e az adott populációban a gyulladásos bélbetegségek valamelyikének kialakulására.
Neoadjuvant systemic therapy in breast cancer
Authors: Kahán Zsuzsanna , Nikolényi Aliz , Uhercsák Gabriella , Thurzó László
Published: December 2008

A neoadjuváns (preoperatív) szisztémás terápia jó lehetőség a lokális-regionális kiterjedésű, tünetet okozó emlőrákok kezelésére. A daganat jellemzői alapján megválasztott elsődleges kemoterápia vagy hormonterápia a legtöbbször a daganat kisebbedéséhez vezet, ami kedvez a későbbi emlőmegtartó műtét elvégzésének. A szisztémás terápia hosszú távú preventív (adjuváns) eredményessége nem különbözik a preoperatív vagy posztoperatív alkalmazás szerint, a terápia hatásának
in vivo
megfigyelt eredménye pedig utal a prognózisra. Végül előny, hogy a műtét előtt bevezetett terápia elvégezhetőségét nem késlelteti esetleges műtéti szövődmény. A neoadjuváns kezelések előtt elengedhetetlen a tumor, illetve a beteg gondos kivizsgálása. Az emlők képalkotó és a tumor szövettani vizsgálata mellett szükség van a beteg teljes kivizsgálására. Fontos a patológiai tipizálás, amely elsősorban a terápia megválasztását, a kemo- vagy hormonszenzitivitás megítélését segíti. A kemoszenzitív tumorok kezelésére leghatékonyabb kombináció a taxán- és antraciklinalapú kemoterápia. Neoadjuváns hormonterápiával főképp menopauzás betegek kezelésével áll rendelkezésre tapasztalat. Valamennyi aromatázgátló effektívebb a tamoxifennél, ezért alkalmazásuk első választásként indokolt. A molekulárisan célzott szerek közül a trastuzumab kemoterápiával kombinálva kiemelkedő hatékonyságot mutat. A primer szisztémás terápia befejezése után újabb stádiummegállapító képalkotó vizsgálat után emlő- és nyirokcsomóműtét következik, és a legtöbbször sugárterápia is. A neoadjuváns szisztémás terápia azonos nyelv és szakmai szabályok alkalmazását követeli meg az összeszokott multidiszciplináris munkacsoport tagjaitól.
Effect of Systemic Intermittent Administration of Human Parathyroid Hormone (RHPTH[1–34]) on the Resistance to Reverse Torque in Rabbit Tibiae
Authors: Corsini Marcelo Soeiro , Faraco Fátima N. , Castro Alessandra A. Pereira , Onuma Tatiana , Sendyk Wilson R. , Shibli Jamil Awad
Published: December 2008

The aim of this study was to evaluate the effect of intermittent administration of human parathyroid hormone [rhPTH (1–34)] on the removal torque of implants placed in rabbit tibiae. Twenty male New Zealand rabbits were submitted to implant surgery. Each animal received one machined screw-type implant (3.75 mm diameter × 8 mm length) in the proximal metaphysis of the right tibia. The rabbits were then divided into 2 groups: the test group (n = 10) received 6 μg/kg of rhPTH (1–34) subcutaneously in the dorsal region 3 days a week, and the control group (n = 10) received placebo. Removal torque was performed at 28 and 56 days after implant placement for both groups. The mean removal torque values at 28 days were 37.0 ± 4.36 Ncm and 47.4 ± 6.77 Ncm for control and test groups respectively (P < .05). At 56 days the reverse torque was 45.8 ± 3.96 Ncm for the control group and 55.8 ± 2.86 Ncm for the test group, indicating that the removal torque was significantly higher in the test groups (P < .05). These results demonstrated that intermittent treatment with rhPTH (1–34) enhanced the removal torque of implants in rabbit tibiae.
Arachidonic Acid and Prostaglandin E2 Influence Human Osteoblast (MG63) Response to Titanium Surface Roughness
Authors: Dean David D. , Campbell Casey M. , Gruwell Scott F. , Tindall John W. M. , Chuang Hui-Hsiu , Zhong Weinan , Schmitz John P. , Sylvia Victor L.
Published: December 2008

Prior studies have shown that implant surface roughness affects osteoblast proliferation, differentiation, matrix synthesis, and local factor production. Further, cell response is modulated by systemic factors, such as 1,25(OH)2D3 and estrogen as well as mechanical forces. Based on the fact that peri-implant bone healing occurs in a site containing elevated amounts of prostaglandin E2 (PGE2), the hypothesis of the current study is that PGE2 and arachidonic acid (AA), the substrate used by cyclooxygenase to form PGE2, influence osteoblast response to implant surface roughness. To test this hypothesis, 4 different types of commercially pure titanium (cpTi) disks with surfaces of varying roughness (smooth Ti, Ra 0.30 μm; smooth and acid etched Ti [SAE Ti], Ra 0.40 μm; rough Ti, Ra 4.3 μm; rough and acid etched Ti [RAE Ti], Ra 4.15μm) were prepared. MG63 osteoblasts were seeded onto the surfaces, cultured to confluence, and then treated for the last 24 hours of culture with AA (0, 0.1, 1, and 10 nM), PGE2 (0, 1, 10, 25, and 100 nM), or the general cyclooxygenase inhibitor indomethacin (0 or 100 nM). At harvest, the effect of treatment on cell proliferation was assessed by measuring cell number and [3H]-thymidine incorporation, and the effect on cell differentiation was determined by measuring alkaline phosphatase (ALP) specific activity. The effect of AA and PGE2 on cell number was somewhat variable but showed a general decrease on plastic and smooth surfaces and an increase on rough surfaces. In contrast, [3H]-thymidine incorporation was uniformly decreased with treatment on all surfaces. ALP demonstrated the most prominent effect of treatment. On smooth surfaces, AA and PGE2 dose-dependently increased ALP, while on rough surfaces, treatment dose-dependently decreased enzyme specific activity. Indomethacin treatment had either no effect or a slightly inhibitory effect on [3H]-thymidine incorporation on all surfaces. In contrast, indomethacin inhibited ALP on smooth surfaces and stimulated ALP on rough. Taken together, the results indicate that both AA and PGE2 influence osteoblast response by promoting osteoblast differentiation on smooth surfaces, while inhibiting it on rough surfaces. Because implants with rough surfaces are acknowledged to be superior to those with smooth surfaces, these results suggest that use of nonsterioidal anti-inflammatory drugs to block PGE2 production and reduce inflammation may be beneficial in the postoperative period after implant placement. They also indicate that manipulation of the AA metabolic pathway may offer a new therapeutic approach for modulating bone healing after implant placement. Because peri-implant healing takes place in a complex cellular environment quite different from the one used in the present study, additional work will be necessary to substantiate these possibilities.
Vertical Alveolar Ridge Expansion and Simultaneous Implant Placement in Posterior Maxilla Using Segmental Osteotomy: Report of Two Cases
Authors: Fujita Atsushi
Published: December 2008

Implant placement in vertically insufficient alveolar ridges of the posterior maxillae may require bone augmentation, such as sinus floor elevation, onlay grafting, and distraction osteogenesis. The purpose of this report is to evaluate the feasibility of vertical alveolar ridge expansion and simultaneous implant placement in the posterior maxilla using segmental osteotomy without sinus floor elevation, onlay grafting, and distraction osteogenesis. Two patients presenting with vertically insufficient alveolar ridges in the posterior maxillae were treated with the surgical procedure as follows. The edentulous ridge was split vertically using a segmental osteotomy before the preparation of an implant bed, and 1 implant body was placed simultaneously in the ridge with the vertical split. Three months later, abutments were connected and prosthetic loading of the implants was started. The follow-up was performed with the aid of dental and panoramic radiographs, evaluation of peri-implant probing depths, and Periotest values. In both patients, alveolar ridge expansion and implant placement were carried out without problems, good functional results were performed, and the clinical and radiologic findings were satisfactory. The outcome of the surgical procedure showed minimal invasion and good functional results.
Clinical and Histomorphometric Evaluation of Staged Approach Using Bone Augmentation and Autogenous Masticatory Mucosal Graft With Endosseous Implant Placement: A Case Report
Authors: Park Jun-Beom
Published: December 2008

Various materials have been used to prevent or minimize ridge collapse after tooth extraction in an attempt to improve implant placement. However, there is no report evaluating the effect the additional autogenous masticatory mucosal graft (free gingival graft [FGG]) on the maturation of the grafted area. A patient who presented with a missing area with prior bone-augmentation procedure was treated with FGG. The additional procedure of FGG performed well as a soft tissue barrier for frenal pull, and the underlying bone showed good healing maturity with a high percentage of new bone formation.
Functions of PIT1 in GATA2-dependent transactivation of the thyrotropin β promoter
Authors: Kashiwabara Yumiko , Sasaki Shigekazu , Matsushita Akio , Nagayama Koji , Ohba Kenji , Iwaki Hiroyuki , Matsunaga Hideyuki , Suzuki Shingo , Misawa Hiroko , Ishizuka Keiko , Oki Yutaka , Nakamura Hirotoshi
Published: December 2008

Thyrotropin (TSH) is a heterodimer consisting of α and β chains, and the β chain (TSHβ) is specific to TSH. The coexistence of two transcription factors, PIT1 and GATA2, is known to be essential for TSHβ expression. Using kidney-derived CV1 cells, we investigated the role of PIT1 in the expression of Tshb gene. GATA2 Zn finger domain, which is known to recognize GATA-responsive elements (GATA-REs), is essential for cooperation by PIT1. Transactivation of TSHβ promoter requires PIT1-binding site upstream to GATA-REs (PIT1-US), and the spacing between PIT1-US and GATA-REs strictly determines the cooperation between PIT1 and GATA2. Moreover, truncation of the sequence downstream to GATA-REs enabled GATA2 to transactivate the TSHβ promoter without PIT1. The deleted region (nt −82/−52) designated as a suppressor region (SR) was considered to inhibit transactivation by GATA2. The cooperation of PIT1 with GATA2 was not conventional synergism but rather counteracted SR-induced suppression (derepression). The minimal sequence for SR was mapped to the 9 bp sequence downstream to GATA-REs. Electrophoretic mobility shift assay suggested that some nuclear factor exists in CV1 cells, which binds with SR and this interaction was blocked by recombinant PIT1. Our study indicates that major activator for the TSHβ promoter is GATA2 and that PIT1 protects the function of GATA2 from the inhibition by SR-binding protein.
Characterization of Oil/Water Flows in Horizontal Pipes
Authors: Vielma M. , Atmaca S. , Sarica C. , Zhang H.
Published: December 2008

The dynamic characteristics of oil/water flow systems have not been understood fully. The need for improved designing methods has led researchers toward its continuous investigation. The objective of this study was to characterize oil/water flow through experimental data. The tests were conducted in a 2-in. horizontal test section using tap water and mineral oil (density = 0.85 g/cm3 and viscosity =15 cp), with superficial velocities ranging from 0.025 to 1.75 m/s. Data were acquired on flow patterns, pressure drop, phase fraction, and droplet size as a function of flow patterns and were used in characterization of the flow and performance evaluation of an oil/water model. A high-speed video camera was used to identify flow patterns and measure droplets, and ten conductivity probes were used to obtain phase distributions. This paper provides new experimental data on pressure drop, holdup, phase distribution, and droplet-size distribution in oil/water flows that can lead to better modeling and design of dispersed systems. Moreover, the new data provide new information on droplet sizes that can have significant impact on separator design. Data comparisons were performed against the data of Trallero (1996). Three probabilistic distributions were tested for fully dispersed flows. A Sauter mean-diameter (SMD) analysis was conducted across the pipe diameter. Droplet-size data were used to evaluate existing models such as Hinze (1955), Kubie and Gardner (1977), Angeli and Hewitt (2000), and Kouba (2003). An empirical correlation to predict the SMD profile of droplets across the pipe cross section was developed for flow pattern of dispersed oil in water (o/w) and water. Log-normal distribution was the best probabilistic distribution for representing the data for fully dispersed systems. The empirical correlation gave acceptable results. More data are needed to validate the results. Model comparisons revealed that none of the models could represent the experimental data accurately. This paper provides significant insight into oil/water flows in horizontal pipes. The results are significant for the design of pipelines and separators. Moreover, the interpretation of production logs in horizontal wells relies heavily on the flow behavior.
A Survey of Wireless Technology for the Oil and Gas Industry
Authors: Petersen Stig , Myhre Bård , Doyle Paula , Mikkelsen Erik , Carlsen Simon , Sjong Dag , Skavhaug Amund , van der Linden Jan Hendrik , Sansom Mark
Published: December 2008

The Institute of Electrical and Electronics Engineers (IEEE) 802.11/a/b/g specifications for wireless local-area networks (WLANs), the IEEE 802.15.4 specification for low-rate wireless personal-area networks, and the radio-frequency-identification (RFID) specifications have enabled a wide range of wireless applications such as wireless networking, sensing, monitoring and control, and asset and personnel tracking. For the oil and gas industry, using this technology will lead to reduced operating costs and will enable new applications.

This paper identifies the technical requirements for wireless technology within the boundaries of the oil and gas industry. Experiments have been performed on wireless solutions within three application areas to examine whether or not currently available technologies fulfill these requirements. The conclusion is that WLAN technology is ready for deployment in oil and gas installations, while there remains a need for an open industrial standard for wireless-sensor networks (WSNs). Regarding RFID, our experiments show that solutions with passive tags are not suitable for asset- and personnel-tracking applications.
Application of Stirling-Cycle Generators in Production Operations
Authors: Dotson Bryan D. , Rochelle Joe M. , Madden Loren
Published: December 2008

Clean, inexpensive, and reliable on-site electric power generation for remote wellsites is an emerging need. There is a growing demand for electric power sources in the range of ½ to 1.5 kW to run pumping units and pumps on liquid loaded gas wells. To understand one possible option, a pilot project consisting of three 0.8-kW Stirling cycle electric generators was conducted in Wyoming.

One generator was installed driving a conventional beam pump at the US Department of Energy's (DOE) Rocky Mountain Oilfield Testing Center (RMOTC). Two generators were installed for telemetry power service on well pads in the Wamsutter gas field. In addition to these two applications, small gas-fired generators could provide power for cathodic protection, chemical dosing systems, and other low-rate pumping requirements.

The pilot demonstrated that a Stirling cycle generator can pump a small well and provide supervisory control and data acquisition (SCADA) power even in cold weather conditions. A simple fuel-control and conditioning system provided reliable operation when properly installed. Operations and maintenance observations from the 1-year pilot are presented.

Stirling cycle engines are external combustion engines which offer some advantages over traditional internal combustion engines: lower maintenance cost, low NOx emissions, and the recovery of heat for process uses. In fact, the current commercial equipment is best thought of as a ¾-kW cogeneration unit.

Introduction

The combination of higher oil and gas prices over the past decade coupled with increasing concern over greenhouse gas emissions has increased the incentive for well operators to use electric-driven production equipment located at the wellsite. In many cases, wells are located far from the traditional electric utility and a remote power source is required. At this time, there are few options to provide the electric power in the ½- to 1.5-kW range at remote wellsites.

Services that can be improved using electric power at wellsites include beam pumping, chemical injection, cathodic protection, and SCADA. In addition, there are potential future services such as gas well deliquification (Dotson et al. 2006) or tank vapor recovery which could be enabled by electric power.

To investigate the potential of a small, low maintenance gas-fired electric generator, three Stirling cycle electric generators were installed in Wyoming.

This paper will outline the alternatives available for low power generation at wellsites. This paper will also show how a gas-fired generator fits into the mix, and why a Stirling cycle generator was selected for testing. The Stirling cycle will be briefly described, followed by the design for power storage and fuel gas supply for the Wyoming installations. The results from both SCADA and well-pumping applications will be provided, along with the overall conclusions from the test.
Development of the Adriatic LNG Terminal Deep Casting Basin Construction Site
Authors: Wesselink Bryan , Tokyay Bora
Published: December 2008

The world's first bottom-founded offshore liquefied natural gas (LNG) storage and regasification terminal is under development by affiliates of Qatar Terminal Limited, ExxonMobil, and Edison for installation in the Northern Adriatic, 15 km east of Porto Levante, Italy. This paper will describe the unique challenges faced and effort undertaken to locate and transform a casting basin to a world-class construction and integration site, including removal of the earthen wall prior to tow-out of the terminal.

The concrete gravity-based structure (GBS) terminal enclosing two 125,000-m3 LNG tanks and supporting 8 GSCM regasification facilities will measure 180 m by 88 m and be located in 29 m of water. These dimensions, as well as proximity to Porto Levante, led to selection of the casting basin in the Spanish Bay of Algeciras as the construction and integration site. The site is under development by the Algeciras Port Authority for use as a container port, and therefore did not have the infrastructure needed to build the terminal. This paper will provide the basis for how parameters such as size, depth, layout, water and electricity supply, accessibility, dredging requirements, lease requirements, availability of workforce, and capacity for growth were established to result in an effective construction and integration site. Some of the execution technologies used for this terminal, such as removal of the earthen wall, installation of regasification facilities, and installation of the LNG tanks will also be described.

The conclusions drawn in this paper can be utilized for upgrading of an existing construction site, or development of a Greenfield site into an effective facility for future GBSs, floating structures, or large-scale construction and integration projects.
Leak Detection in Subsea Pipeline: A Mechanistic Modeling Approach With Fixed Pressure Boundaries
Authors: Gajbhiye R. N. , Kam S. I.
Published: December 2008

This study shows how a subsea pipeline leak can be modeled in a mechanistic way. Special attention is paid to the implication of fixed-pressure boundary conditions at both upstream and downstream locations, which is relevant to the way the majority of field operations are actually performed. The use of fixed-pressure boundary conditions leaves the change in inlet total flow rate (Δqtin) and the change in outlet total flow rate (Δqtout) as two possible leak-detection indicators that can be monitored on a realtime basis. The two-phase flow of gas and oil mixtures in subsea pipelines is analyzed by using Beggs and Brill's correlations. The effect of different parameters on the mechanistic leak-detection modeling is also investigated, accounting for gas compressibility, backpressure of the system, pressure drop across the system, and gas/oil fraction at the leak.

Also presented in this study is a new method to predict the change in inlet or outlet total flow rates (Δqtin or (Δqtout) in a form of contours with dimensionless leak opening size (dleak/D) and dimensionless leak position (xleak/L) in x and y axes. This new style of reporting leak-detection indicators is believed to provide a convenient means to improve data interpretation in actual field practice and laboratory tests.
Energy-Efficient Operation of Gas Export Systems
Authors: Nørstebø V. S. , Bakken L. E. , Dahl H. J.
Published: December 2008

The gas transport system on the Norwegian continental shelf (NCS) consists of 7800 km of pipelines and is the largest offshore network of its kind in the world. Natural gas is processed at treatment plants in Norway, and dry gas is exported through pipelines to customers in the UK and continental Europe. These customers have the opportunity to make varying gas delivery nominations, and meeting such sales gas commitments is important.

A major challenge is to operate the network at minimum cost, with minimum environmental emissions, fulfilling variations in contractual nominations and maintaining a sufficient pipeline inventory* to provide operational flexibility.

Optimum pipeline inventory and optimum operation of export compressors have been analyzed in earlier studies.

The scope of the work presented in this paper is to establish a model for optimum operation of a gas export system, including customer nominations and operation of pipelines and compressor stations. That implies improving system energy efficiency, reducing environmental emissions, and maintaining sufficient availability and export deliverability.† The model will provide guidelines which will be implemented in planning and operation of the gas export system.

This model is based on analyzes of operational data from the gas export system on the NCS. The data are analyzed using statistical and simulation software.

The paper describes the established model for optimum operation of the system, where specific power consumption is minimized. A case study which illustrates the use of the model is also presented. Furthermore, the paper reports on a cost-benefit analysis based on the established model.
Effects of Temperature Gradients in Batch Kraft Cooking of Wood Species Mixtures
Authors: Jain Sandeep , Mortha Gérard F
Published: December 2008

A batch kraft cooking non-isothermal digester was modelled based on chemical kinetics and mass transfer equations for softwood. Kraft pulping modelling had been designed for non-isothermal batch cooks of chip mixtures: either mixed-size chips, according to a thickness distribution law, or mixtures of different wood species. The case of existing linear or non-linear radial temperature gradients in a digester was examined. Several chip populations with different thickness distribution were used: normal (major abundance of 3-5 mm chips); uniform (equal abundance of chips in the range 3-12 mm); Gaussian-type (centred on 7 mm chips); Poisson-type (major abundance of 3 mm chips). The effect on cooking results due to temperature gradients in digester was predicted along with the existing non-uniformity arising from the effect of chip size distribution, density, and wood mixtures of different composition and chemical properties (rate constants, activation energies). Results are presented as a kappa number, yield and rejects distributions and mean values. The rather sharp kappa number distributions obtained for isothermal cooks were found to be severely spread in the linear temperature gradient case. The above effects were attenuated when a central core in the digester was kept isothermal. The stratification of chips resulted in significantly reduced width in kappa number distributions. Highest density chips cooked lower; however, since diffusion effects were more prominent in them, their apparent activation energy was also less. So they were slightly less affected by temperature gradients in the digester. Cooking different wood species together also affected the spread of the kappa number distribution. This cumulated more or less to temperature gradients effects, depending on chemical activation energy data and possible differences between species.
The Production of Syngas by Dry Reforming in Membrane Reactor Using Alumina-Supported Rh Catalyst: A Simulation Study
Authors: Kumar Shashi , Agrawal Mohit , Kumar Surendra , Jilani Sheeba
Published: December 2008

A one-dimensional, isothermal mathematical model for methane reforming with carbon dioxide in a conventional fixed bed reactor (FBR) and a porous Vycor glass membrane reactor (MR) has been developed. The reactors are packed with alumina-supported Rh catalyst. A simulation study shows that conversion of methane is higher in MR than that of FBR at all temperatures. In order to analyze the overall performance of MR, a detailed simulation study has been carried out to elucidate the effect of temperature, sweep gas flow rate, dilution ratio, feed ratio on percent conversion of methane, yield of hydrogen and carbon monoxide, and ratio of hydrogen to carbon monoxide in produced syngas. Besides, a comprehensive investigation on the effectiveness of the catalysts for methane reforming with carbon dioxide reaction has been made and presented.