bluuebunny/crossref_metadata_2025 huggingface dataset:
How can dental public health competencies be addressed at the undergraduate level?
Authors: Brondani Mario A. , Pattanaporn Komkham , Aleksejuniene Jolanta
Published: September 2014

Objectives

To discuss the extent to which an undergraduate dental module addresses dental public health competencies via its different learning pedagogies and to explore the relevance of students' written reflections on these dental public health competencies.

Methods

This article uses a literature review to situate the extent to which dental public health competencies are addressed by the University of British Columbia undergraduate dental module entitled “Professionalism and Community Services” (PACS). It also uses students' written individual self‐reflections (between 100 and 500 words) on community service learning activities to critically illustrate how dental public health competencies support their learning.

Results

The PACS dental module is delivered to undergraduate students in all 4 years, more than 190 in total, and addresses six dental public health competencies, including oral health promotion, ethics, and evidence‐based practice. The multifaceted pedagogical approach employed to discuss aspects of dentistry related to dental public health includes guest lectures, community activities, small group activities, self‐reflection, and reports.

Conclusions

Given the falling number of dental public health professionals in North America, the discussed undergraduate pedagogy aims to sensitize future dentists to a career focused on dental public health. Through reflections, students pondered ideas related to dental public health; they also engaged in developing meaningful activities in various underserved communities. Further studies are needed to evaluate the influence of this community‐based curriculum upon students' practice choice.
Socioeconomic and racial/ethnic oral health disparities among US older adults: oral health quality of life and dentition
Authors: Huang Deborah L. , Park Mijung
Published: September 2014

Objective

This study aims to examine if older adults living in poverty and from minority racial/ethnic groups experienced disproportionately high rates of poor oral health outcomes measured by oral health quality of life (OHQOL) and number of permanent teeth.

Methods

Cross‐sectional analysis of 2,745 community‐dwelling adults aged ≥65 years from the National Health and Nutrition Examination Survey (NHANES) 2005‐2008. Oral health outcomes were assessed by questionnaire using the NHANES‐Oral Health Impact Profile for OHQOL and standardized examination for dentition. Logistic and linear regression analyses were used to determine the association between oral health outcomes and predictors of interest. All analyses were weighted to account for complex survey sampling methods.

Results

Both poverty and minority race/ethnicity were significantly associated with poor oral health outcomes in OHQOL and number of permanent teeth. Distribution of scores for each OHQOL domain varied by minority racial/ethnic group.

Conclusions

Oral health disparities persist in older adults living in poverty and among those from minority racial/ethnic groups. The racial/ethnic variation in OHQOL domains should be further examined to develop interventions to improve the oral health of these groups.
Population pharmacokinetics of rifampin in the treatment of Mycobacterium tuberculosis in Asian elephants
Authors: Egelund E. F. , Isaza R. , Brock A. P. , Alsultan A. , An G. , Peloquin C. A.
Published: September 2014

The objective of this study was to develop a population pharmacokinetic model for rifampin in elephants. Rifampin concentration data from three sources were pooled to provide a total of 233 oral concentrations from 37 Asian elephants. The population pharmacokinetic models were created using Monolix (version 4.2). Simulations were conducted using ModelRisk. We examined the influence of age, food, sex, and weight as model covariates. We further optimized the dosing of rifampin based upon simulations using the population pharmacokinetic model. Rifampin pharmacokinetics were best described by a one‐compartment open model including first‐order absorption with a lag time and first‐order elimination. Body weight was a significant covariate for volume of distribution, and food intake was a significant covariate for lag time. The median Cmax of 6.07 μg/mL was below the target range of 8–24 μg/mL. Monte Carlo simulations predicted the highest treatable MIC of 0.25 μg/mL with the current initial dosing recommendation of 10 mg/kg, based upon a previously published target AUC0–24/MIC > 271 (fAUC > 41). Simulations from the population model indicate that the current dose of 10 mg/kg may be adequate for MICs up to 0.25 μg/mL. While the targeted AUC/MIC may be adequate for most MICs, the median Cmax for all elephants is below the human and elephant targeted ranges.
Diet and prey preferences of dholes (Cuon alpinus): dietary competition within Asia's apex predator guild
Authors: Hayward M. W. , Lyngdoh S. , Habib B.
Published: September 2014

Group‐hunting predators theoretically benefit from hunting together through increased prey returns; however, studies on lions suggest food is not enough. The dhole is one such group hunter; however, its predatory role within Asia's large predator guild is less well known than other members. We tested whether dholes exhibit preferential predation, and determined the drivers of prey choice and whether pack size affected diet to ascertain the fundamental resources required for the species' conservation, given lack of a prey base is the primary threat to this species. We reviewed the literature and found 24 studies from 16 sites from throughout the species extant range that reported on 8816 records (scat + kills) of 19 species. Jacobs' index revealed that sambar Rusa unicolor, chital Axis axis and wild boar Sus scrofa contribute almost two‐thirds of the food biomass of the dhole, with sambar being significantly preferred. Sambar are at the upper end of the accessible prey spectrum (30–235 kg), and are marginally above the preferred weight range of 130–190 kg. The accessible prey spectrum extensively overlaps with leopards and tigers in Asia and reflects the extensive dietary competition within Asia's large predator guild, as tigers also preferentially prey on sambar and leopards completely overlap in the accessible prey with dholes. Although prey preferences are not affected by pack size, larger packs ultimately take larger prey. This study documents for the first time the critical prey resources necessary for the conservation of dholes in Asia, and highlights the degree of competition potentially occurring across dhole distribution range.
Effects of body size, habitat selection and exposure on hatchling turtle survival
Authors: Paterson J. E. , Steinberg B. D. , Litzgus J. D.
Published: September 2014

Iteroparous species invest little energy into annual reproduction and tend to experience low and variable survivorship in young life stages. However, juveniles with traits that increase survival will have a fitness advantage over conspecifics, and usually bigger is better for juvenile vertebrates. Understanding behavioural and morphological characteristics that increase fitness is important for our understanding of the evolution of life‐history strategies. We outfitted naturally emerging hatchlings of two species of turtles (Blanding's turtles Emydoidea blandingii and wood turtles Glyptemys insculpta) with radio transmitters to test five hypotheses related to survival from nests to overwintering sites using logistic regression models. In contrast to the widely supported hypothesis that bigger is better for survival of juveniles, we found that smaller hatchlings of both species were more likely to survive from emergence to overwintering. In E. blandingii, hatchlings that emerged later in the year, which reduced exposure time to predators and environmental risks, and spent less time in upland open habitat, were also more likely to survive. Our results demonstrate that bigger is not always better in juvenile ectotherms. Assuming bigger is better without observations of survival can lead to erroneous conclusions related to fitness proxies and the ontogeny of body size in populations. The observed relationship between habitat selection and survival in E. blandingii indicates a direct link between behaviour (habitat selection) and fitness through mortality caused by predators and environmental stressors.
Genomic atolls of differentiation in coral reef fishes (Hypoplectrusspp.,Serranidae)
Authors: Puebla O. , Bermingham E. , McMillan W. O.
Published: September 2014

Because the vast majority of species are well diverged, relatively little is known about the genomic architecture of speciation during the early stages of divergence. Species within recent evolutionary radiations are often minimally diverged from a genomic perspective, and therefore provide rare opportunities to address this question. Here, we leverage the hamlet radiation (Hypoplectrusspp., brightly coloured reef fishes from the tropical western Atlantic) to characterize genomic divergence during the early stages of speciation. Transect surveys and spawning observations in Belize, Honduras and Panama confirm that sympatric barred (H. puella), black (H. nigricans) and butter (H. unicolor) hamlets are phenotypically distinct and reproductively isolated, although hybrid spawnings and individuals with intermediate phenotypes are seen on rare occasions. A survey of approximately 100 000 restriction site‐associatedSNPs in 126 samples from the three species across the three replicate populations reveals extremely slight genomewide divergence among species (FST = 0.0038), indicating that ecomorphological differences and functional reproductive isolation are maintained in sympatry in a backdrop of extraordinary genomic similarity. Nonetheless, a very small proportion ofSNPs (0.05% on average) are identified asFSToutliers among sympatric species. Remarkably, a singleSNPis identified as an outlier in repeated populations for the same species pair. A minicontig assembledde novoaround thisSNPfalls into the genomic region containing theHoxCa10andHoxCa11genes in 10 teleost species, suggesting an important role forHoxgene evolution in this radiation. This finding, if confirmed, would provide a better understanding of the links between micro‐ and macroevolutionary processes.
Novel molecular approach demonstrates that turbid river plumes reduce predation mortality on larval fish
Authors: Carreon‐Martinez Lucia B. , Wellband Kyle W. , Johnson Timothy B. , Ludsin Stuart A. , Heath Daniel D.
Published: September 2014

Turbidity associated with river plumes is known to affect the search ability of visual predators and thus can drive ‘top‐down’ impacts on prey populations in complex ecosystems; however, traditional quantification of predator–prey relationships (i.e. stomach content analysis) often fails with larval fish due to rapid digestion rates. Herein, we use novel molecular genetic methods to quantify larval yellow perch (YP) in predator stomachs in western Lake Erie to test the hypothesis that turbidity drives variation in larval predation. We characterize predator stomach contentDNAto first identifyYP DNA(single nucleotide polymorphism) and then quantify larvalYPpredation (microsatellite allele counting) in two river plumes differing in turbidity. Our results showed elevated larvalYPpredation in the less turbid river plume, consistent with a top‐down impact of turbidity on larval survival. Our analyses highlight novel ecological hypothesis testing using the power of innovative molecular genetic approaches.
Pseudomonas corrugata crpCDE is part of the cyclic lipopeptide corpeptin biosynthetic gene cluster and is involved in bacterial virulence in tomato and in hypersensitive response in Nicotiana benthamiana
Authors: Strano Cinzia Patricia , Bella Patrizia , Licciardello Grazia , Fiore Alberto , Lo Piero Angela Roberta , Fogliano Vincenzo , Venturi Vittorio , Catara Vittoria
Published: September 2014

Pseudomonas corrugata CFBP 5454 produces two kinds of cyclic lipopeptides (CLPs), cormycin A and corpeptins, both of which possess surfactant, antimicrobial and phytotoxic activities. In this study, we identified genes coding for a putative non‐ribosomal peptide synthetase and an ABC‐type transport system involved in corpeptin production. These genes belong to the same transcriptional unit, designated crpCDE. The genetic organization of this locus is highly similar to other Pseudomonas CLP biosynthetic clusters. Matrix‐assisted laser desorption ionization‐time of flight‐mass spectrometry (MALDI‐TOF‐MS) analysis revealed that transporter and synthetase genomic knock‐out mutants were unable to produce corpeptins, but continued to produce cormycin A. This suggests that CrpCDE is the only system involved in corpeptin production in P. corrugata CFBP 5454. In addition, phylogenetic analysis revealed that the CrpE ABC transporter clustered with the transporters of CLPs with a long peptide chain. Strains depleted in corpeptin production were significantly less virulent than the wild‐type strain when inoculated in tomato plants and induced only chlorosis when infiltrated into Nicotiana benthamiana leaves. Thus, corpeptins are important effectors of P. corrugata interaction with plants. Expression analysis revealed that crpC transcription occurs at high cell density. Two LuxR transcriptional regulators, PcoR and RfiA, have a pivotal role in crpC expression and thus in corpeptin production.
Comparing lung ultrasound with bioimpedance spectroscopy for evaluating hydration in peritoneal dialysis patients
Authors: Paudel Klara , Kausik Tarun , Visser Annemarie , Ramballi Cheryl , Fan Stanley L
Published: September 2014

Background

Bioimpedance spectroscopy (BIS), ultrasound lung comets (ULC) and serum biomarkers (N‐terminal pro–brain natriuretic peptide, NT‐proBNP) have all been used to assist clinicians to determine hydration status in dialysis patients.

Methods

We performed simultaneous BIS, ULC and NT‐proBNP measurements in 27 peritoneal dialysis patients to determine the concordance of the three methods.

Results

Patients with evidence of increasing lung congestion (as determined by ultrasound) were more likely to be diabetic, have systolic hypertension and have higher NT‐proBNP (r = 0.65, P < 0.0005). Although there was a trend for patients with high ULC to be overhydrated as determined by BIS, this did not reach statistical significance. Moreover, the correlation between BIS and NT‐proBNP (though statistically significant at r = 0.47, P < 0.02) appeared to be weaker.

Conclusion

BIS and ULC may be complementary, providing different information, whereas BIS may be more specific to hydration. ULC and NT‐proBNP may indicate left ventricular failure coexisting with overhydration.
Pathogen‐inducedSGT1 ofArachis diogoiinduces cell death and enhanced disease resistance in tobacco and peanut
Authors: Kumar Dilip , Kirti Pulugurtha Bharadwaja
Published: September 2014

We have identified a transcript derived fragment (TDF) corresponding toSGT1in a study of differential gene expression on the resistant wild peanut,Arachis diogoi, upon challenge from the late leaf spot pathogen,Phaeoisariopsis personata, and cloned its full‐lengthcDNAfollowed by subsequent validation through q‐PCR. Sodium nitroprusside, salicylic acid, ethephon and methyl jasmonate induced the expression ofAdSGT1, while the treatment with abscisic acid did not elicit its up‐regulation. AdSGT1 is localized to both nucleus and cytoplasm. Its overexpression induced hypersensitive‐like cell death in tobacco under transient conditional expression using the estradiol system, and this conditional expression ofAdSGT1was also associated with the up‐regulation ofNtHSR203J,HMGRandHIN1, which have been shown to be associated with hypersensitive response in tobacco in earlier studies. Expression of thecDNAin a susceptible cultivated peanut variety enhanced its resistance against the late leaf spot pathogen,Phaeoisariopsis personata, while the heterologous expression in tobacco enhanced its resistance againstPhytophthora parasiticavar.nicotianae,Alternaria alternatavar.nicotianaeandRhizoctonia solani. Constitutive expression in peanut was associated with the co‐expression of resistance‐related genes, CC‐NB‐LRR and some protein kinases.
A Mimic of Self‐Healing Juvenile Cutaneous Mucinosis?
Authors: Williams Charles A. , Merkel Kimberly L.
Published: September 2014

A 14‐year‐old boy presented with a chronic history of atypical papular mucinosis consisting of multiple subcutaneous nodules and confluent papular skin lesions. He initially presented at age 2 years with the rapid onset of numerous subcutaneous nodular lesions that completely resolved over a period of years. Clinical and histologic evidence, together with his clinical course, were suggestive of self‐healing juvenile cutaneous mucinosis (SHJCM), but a few years later, during childhood, he experienced a recurrence of the subcutaneous nodules involving the limbs, trunk, and face, in addition to new findings of multiple flesh‐colored papules coalescing into plaques on his neck and back. Although his early childhood course and histologic picture were suggestive of SHJCM, the progressive nature of his disorder is not like that seen in SHJCM and appears different from other reported disorders involving cutaneous mucinosis.
From the Politics of Antagonistic Recognition to Agonistic Peace Building: An Exploration of Symbols and Rituals in Divided Societies
Authors: Nagle John
Published: September 2014

The inclusion of symbols and rituals in peace agreements is often based on the politics of recognition, in which the cultural identities of oppositional groups are awarded equal status in society. Moreover, it is often assumed that the successful regulation of conflicts over symbols and rituals is dependent on the resolution of seemingly more important issues that divide warring groups, like demilitarization and the reform of the justice system and the government. Yet, symbols and rituals generate specific problems that merit the design of innovative mechanisms to ensure peaceful stability in divided societies. This article explores how the politics of recognition often fails to successfully regulate violent conflict and instead creates a context for destructive intergroup clashes. It further assesses the potential of creating shared symbols and rituals, as well as reframing their meaning, before finally proposing Chantal Mouffe's concept of agonism, the process in which violent group‐based antagonism is channeled into peaceful and democratic contestation.
Thin slices of infidelity: Determining whether observers can pick out cheaters from a video clip interaction and what tips them off
Authors: LAMBERT NATHANIEL M. , MULDER SETH , FINCHAM FRANK
Published: September 2014

The viability of using brief observations of behavior (thin slicing) to identify infidelity in romantic relationships was examined. Two studies supported the hypothesis that observers can accuratelsy identify people who are cheating on their romantic dating partner based on thin slices of observed behavior. In Study 1, raters were able to accurately identify people who were cheating on their romantic dating partner after viewing a short 3‐ to 4‐min video of the couple interacting. Study 2 replicated this finding and identified possible variables that may mediate the relation between coder's ratings and participants' actual reported infidelity. Commitment and trustworthiness were found to be mediators of this relation. These results are discussed in terms of application and future research.
Simultaneous registration of gnomonic projections and central perspectives
Authors: Barazzetti Luigi , Previtali Mattia , Scaioni Marco
Published: September 2014

An innovative methodology that combines central perspectives and panoramic gnomonic projections into an integrated bundle block adjustment is discussed. The use of both kinds of images generates metric products with a superior level of detail (image resolution) compared with conventional central perspectives alone, whilst achieving the accuracy of the latter. The entire methodology is intended as a low‐cost solution to improving the ground sampling distance over that achievable with single exposures by conventional modern terrestrial cameras. Very high‐resolution close‐range images can be automatically generated and oriented with a rigorous multi‐step procedure that integrates both types of images within a unified least squares adjustment. The advantages and disadvantages of the proposed approach are analysed from both theoretical and practical points of view and illustrated through a series of examples.
Evaluation of structure from motion for soil microtopography measurement
Authors: Nouwakpo Sayjro K. , James Mike R. , Weltz Mark A. , Huang Chi‐Hua , Chagas Isis , Lima Luiz
Published: September 2014

Recent developments in low‐cost structure‐from‐motion (SfM) technologies offer new opportunities for geoscientists to acquire high‐resolution soil microtopography data at a fraction of the cost of conventional techniques. However, these new methodologies often lack easily accessible error metrics and hence are difficult to evaluate. In this research, a framework was developed to evaluate a SfM approach for soil microtopography measurement through assessment of uncertainty sources and quantification of their potential impact on overall 3D reconstruction. Standard deviations of camera interior orientation parameters estimated from SfM self‐calibration within five different soil surface models were several orders of magnitude larger than precisions expected from pattern‐based camera calibration. Sensitivity analysis identified the principal point position as the dominant source of calibration‐induced uncertainty. Overall, surface elevation values estimated from both technologies were similar in magnitude with a root mean square (RMS) of elevation difference of 0·2 mm. Nevertheless, the presence of deformation in either SfM or traditional photogrammetric point clouds highlights the importance of quality assurance safeguards (such as a judicious choice of control points) in SfM workflows for soil microtopography applications.
Characterization ofPseudomonas syringaepv.actinidiae(Psa) isolated from France and assignment of Psa biovar 4 to ade novopathovar:Pseudomonas syringaepv.actinidifoliorumpv. nov.
Authors: Cunty A. , Poliakoff F. , Rivoal C. , Cesbron S. , Fischer‐Le Saux M. , Lemaire C. , Jacques M. A. , Manceau C. , Vanneste J. L.
Published: September 2014

Since 2008, bacterial canker of kiwifruit (Actinidia deliciosaandA. chinensis) caused byPseudomonas syringaepv.actinidiae(Psa) has resulted in severe economic losses worldwide. Four biovars of Psa can be distinguished based on their biochemical, pathogenicity and molecular characteristics. Using a range of biochemical, molecular and pathogenicity assays, strains collected in France since the beginning of the outbreak in 2010 were found to be genotypically and phenotypically diverse, and to belong to biovar 3 or biovar 4. This is the first time that strains of biovar 4 have been isolated outside New Zealand or Australia. A multilocus sequence analysis based on four housekeeping genes (gapA,gltA,gyrBandrpoD) was performed on 72 strains representative of the French outbreak. All the strains fell into two phylogenetic groups: one clonal corresponding to biovar 3, and the other corresponding to biovar 4. This second phylogenetic group was polymorphic and could be divided into four lineages. A clonal genealogy performed with a coalescent approach did not reveal any common ancestor for the 72 Psa strains. Strains of biovar 4 are substantially different from those of the other biovars: they are less aggressive and cause only leaf spots whereas Psa biovars 1, 2 and 3 also cause canker and shoot die‐back. Because of these pathogenic differences, which were supported by phenotypic, genetic and phylogenetic differences, it is proposed that Psa biovar 4 be renamedPseudomonas syringaepv.actinidifoliorumpv. nov. StrainCFBP8039 is designated as the pathotype strain.
On the Thomas–Fermi Approximation of the Ground State in a ‐Symmetric Confining Potential
Authors: Gallo Clément , Pelinovsky Dmitry
Published: September 2014

For the stationary Gross–Pitaevskii equation with harmonic real and linear imaginary potentials in the space of one dimension, we study the ground state in the limit of large densities (large chemical potentials), where the solution degenerates into a compact Thomas–Fermi approximation. We prove that the Thomas–Fermi approximation can be constructed by using the unstable manifold theorem for a planar dynamical system. To justify the Thomas–Fermi approximation, the existence problem can be reduced to the Painlevé‐II equation, which admits a unique global Hastings–McLeod solution. We illustrate numerically that an iterative approach to solving the existence problem converges but give no analytical proof of this result. Generalizations are discussed for the stationary Gross–Pitaevskii equation with harmonic real and localized imaginary potentials.
The Growing Economic Presence of China in the Caribbean
Authors: Bernal Richard L.
Published: September 2014

China's economic presence in the Caribbean has grown significantly in the last decade. The growing economic presence of China in the Caribbean is evident in China's exports and development assistance to the region. Caribbean exports to China have not significantly increased; in fact, they declined during the period 2006–09. This is in contrast to the growth of exports from Latin America and the rest of the world and represents a missed opportunity for Caribbean exporters. The potential for further growth in economic relations between China and the Caribbean lies in trade including services, foreign investment and tourism. The pattern of trade, investment and development assistance in the Caribbean is very different from that in Latin America, and therefore it is misleading to conflate the two regions and draw an inference of similarity beyond very broad trends as is the case of the literature on the economic presence of China in Latin America. The contrast is vividly evident in the fact that China is now the largest trade partner of some Latin American countries but remains a small fraction of the Caribbean's trade.
Compressible Liquid Impact Against a Rigid Body
Authors: Dyment Arthur
Published: September 2014

Impingement of a water jet on a rigid wall and entry of a rigid body into water are subject to common effects of compressibility, occurring during a very short period. Thanks to order of magnitude estimates and application of the fundamental laws of conservation, the extent and the duration of the domain of highly compressed water are obtained in terms of the Mach number and of the curvature at the tip of the jet, or of the projectile. The model works for jet fronts and body profiles of any shape.
Effect of Radial Temperature Gradient on the Stability of Magnetohydrodynamic Dean Flow in an Annular Channel at High Magnetic Parameter
Authors: Dholey S.
Published: September 2014

The effect of a radial temperature gradient on the stability of Dean flow of an electrically conducting fluid in an annular channel is investigated. A strong constant magnetic field is imposed in the axial direction. Finite-difference method is used to solve the eigenvalue problem. For given values of gap width d, between the cylinders, and magnetic parameter Q, electrically nonconducting (NC) walls are found to be more destabilizing than perfectly conducting (PC) walls when the temperature parameter N < 0. This trend persists even for small positive values of N but when N (>0) exceeds a critical value depending on Q, PC walls are slightly more destabilizing than NC walls. The critical value of the radii ratio η (0 < η < 1) beyond which the first unstable mode becomes nonaxisymmetric is determined for various values of N and Q.
Parameter Estimation of the FitzHugh–Nagumo Neuron Model Using Integrals Over Finite Time Periods
Authors: Concha Antonio , Garrido Rubén
Published: September 2014

This paper proposes two methodologies for estimating the parameters of the FitzHugh–Nagumo (FHN) neuron model. The identification procedures use only measurements of the membrane potential. The first technique is named the identification method based on integrals and wavelets (IMIW), which combines a parameterization based on integrals over finite time periods and a wavelet denoising technique for removing the measurement noise. The second technique, termed as the identification method based only on integrals (IMOI), does not use any wavelet denoising technique and attenuates the measurement noise by integrating the IMIW parameterization two times more over finite time periods. Both procedures use the least squares algorithm for estimating the FHN parameters. Integrating the FHN model over finite time periods allows eliminating the unmeasurable recovery variable of this model, thus obtaining a parameterization based on integrals of the measurable membrane potential variable. Unlike an identification technique recently published, the proposed methods do not rely on the time derivatives of the membrane potential and are not limited to continuously differentiable input current stimulus. Numerical simulations show that both the IMIW and IMOI have a good and a similar performance, however, the implementation of the latter is simpler than the implementation of the former.
Injection of Propidium Iodide into HeLa Cells Using a Silicon Nanoinjection Lance Array
Authors: Lindstrom Zachary K. , Brewer Steven J. , Ferguson Melanie A. , Burnett Sandra H. , Jensen Brian D.
Published: September 2014

Delivering foreign molecules into human cells is a wide and ongoing area of research. Gene therapy, or delivering nucleic acids into cells via nonviral or viral pathways, is an especially promising area for pharmaceutics. All gene therapy methods have their respective advantages and disadvantages, including limited delivery efficiency and low viability. We present an electromechanical method for delivering foreign molecules into human cells. Nanoinjection, or delivering molecules into cells using a solid lance, has proven to be highly efficient while maintaining high viability levels. This paper describes an array of solid silicon microlances that was tested to determine efficiency and viability when nanoinjecting tens of thousands of HeLa cells simultaneously. Propidium iodide (PI), a dye that fluoresces when bound to nucleic acids and does not fluoresce when unbound, was delivered into cells using the lance array. Results show that the lance array delivers PI into up to 78% of a nanoinjected HeLa cell culture, while maintaining 78–91% viability. With these results, we submit the nanoinjection method using a silicon lance array as another promising particle delivery method for mammalian culture cells.
Analysis of Turbulent Swirling Flow in an Isothermal Gas Turbine Combustor Model
Authors: Benim A. C. , Iqbal S. , Nahavandi A. , Meier W. , Wiedermann A. , Joos F.
Published: September 2014

Isothermal turbulent swirling flow in a model combustor is computationally and experimentally investigated. The main purpose was the validation of turbulence models for this flow type. The experiments were carried out at the German Aerospace Centre (DLR), Stuttgart. For the modeling, the validation of the LES approach, applying the Smagorinsky subgrid-scale model, using wall-functions, takes a central role in the present study. URANS calculations based on SST and RSM were also performed. An analysis for LES showed that a sufficient resolution is indeed obtained for grid index values proposed in the literature. It was also observed that coarser grids can still deliver useful results. LES results were observed to be quite accurate, except the swirl velocity in the outer parts of the jet, which was under-predicted. URANS results were not that good, whereas the RSM performed better than the SST, especially in predicting the swirl velocity in the outer parts. An investigation performed on different domain sizes indicated that the outlet boundary formulation has some influence on the prediction of the upstream flow. The influence of the differencing scheme on LES was also investigated.
Five-Axis Flank Milling for Design and Manufacture of Turbocharger Compressor Impeller
Authors: Bi QingZhen , Chen Hua , Zou Xueqi , Zhu LiMin , Ding Han
Published: September 2014

Modern turbocharging has imposed multiply stringent requirements on turbocharger compressor impellers. They must be highly efficient and quiet in operation, have longevity in service, be cheaply made and be quick to market. The traditionally cast compressor impellers are struggling to meet these demands. The turbocharger compressor impellers machined from solid have many advantages in geometric accuracy, material property and design-to-production time compared with their cast counterpart. However, the benefits of machined impeller had been hindered by high manufacturing cost. The high cost comes mainly from long machining time with traditional five-axis point milling. Compared with the point milling, five-axis flank milling has much higher material removal rate, and this significantly reduces machining cost and makes machining from solid competitive. Turbocharger industry uses to design their impellers for casting or five-axis point-milling, and the impeller blade surfaces are usually freeform surfaces. Current CAM (Computer Aided Manufacture) software has provided flank milling function for smooth straight-line-surfaces (SLS), but they cannot handle the freeform surfaces. The conversion from arbitrary surface to SLS becomes necessary. The conversion method has been developed, but few of them concern the important manufacturing constraints such as the smoothness of cutter movement and the developability of the SLS. Furthermore, the conversion may be used in the manufacturing process only, and the effect of the deviation between the original freeform surface and the SLS may be ignored. In this paper, we put forward a new approach. First a flank milling conversion method is described. It takes into account of important manufacturing constraints when converting an arbitrary surface into a SLS. The method is fast and produces good approximation. Next we describe how the method can be integrated into daily impeller design suite to make impeller design and subsequent manufacturing more effective. The approach is illustrated and verified by the design and machining experiment of a turbocharger impeller.
Improved Generating Reliability of Mature Technology Gas Turbines for Supplying Critical Industrial and Commercial Loads for General Electric Company of Libya (GECOL)
Authors: Holland Howard W. , Fathulla Sally
Published: September 2014

Contractors can add value for their clients when they effectively manage operating risks within their areas of core competence. General Electric Company of Libya (GECOL) had operated its mature gas turbine generating plants at maximum output with severely constrained maintenance budgets for years. GECOL prolonged operation of many of its facilities supplying critical industrial and commercial loads until material failures shut them down. In addition, facilities under construction suffered from a lack of technical due diligence and quality assurance scrutiny.

This paper covers the loss-of-load risk management techniques recommended following a Willbros assessment of GECOL’s major combustion turbine generating facilities. The assessment was completed immediately prior to the recent regime change and resulted in recommended strategies for managing new construction and outage work under existing maintenance budget constraints. Plants assessed included Zawia, Khoms, Tripoli South, Western Mountain, Benghazi North and Zewitena.
Application of Artificial Neural Networks for the Prediction of Pollutant Emissions and Outlet Temperature in a Fuel-Staged Gas Turbine Combustion Rig
Authors: Lamont Warren G. , Roa Mario , Lucht Robert P.
Published: September 2014

This study deals with artificial neural network (ANN) modelling of a fuel-staged gas turbine combustion rig to predict exhaust emissions and combustor outlet temperature. The data used for ANN training and testing was acquired from a natural gas burning test rig at various operating conditions. The ANN model uses a multi-layer feed-forward network architecture and was trained with experimental data using backpropagation. The ANN has 8 input neurons, 27 neurons in the hidden layer and 3 output neurons. The ANN model can predict the experimental results quite well with correlation coefficients in the range of 0.96 to 0.99. The ANN model was then used to create performance maps (response surfaces) and to predict two operating conditions that optimize the conflicting criteria of low emissions and high gas outlet temperature. The ANN predicted optimum operating conditions yielded NOx emissions below 20 ppm corrected to 15% O2 and a combustor outlet temperature of 1838 K. These optimum operating conditions were then experimental validated. The experimental validation showed that the first ANN predicted optimum operating condition was poorly predicted: the difference between the ANN predicted equivalence ratio and that of the experimental validation data for the optimum point was over 0.1. The second ANN predicted optimum operating condition was accurately predicted within the experimental uncertainty of the measurements. The difference in validity between the ANN predictions can be attributed to the sparsity of the data: for the first optimum operating condition there were 28 highly clustered training points, while the second optimum operating condition had 40 points that spanned a greater operating region.
Comparative Study of Using Water and R-134a as Cooling Medium in the Condenser of a Steam Power Plant
Authors: Yousef Khaled , Assefa Abebayehu , Hegazy Ahmed , Engeda Abraham
Published: September 2014

This paper presents a comparative analytical study of using water and R-134a as cooling medium in the condenser of a steam power plant (SPP). In this study, a shell-and-tube cross-flow heat exchanger has been considered. Because of its direct effect on cycle thermal efficiency, the condenser of the SPP has been continuously improved over the years. One of the ways of increasing the performance of a SPP is by reducing the condenser pressure and using low temperature cooling medium in the condenser. The lower the temperature of the cooling fluid circulating through the condenser tubes, the faster will be the steam condensation. This process increases the condensation rate as well as condenser heat transfer rate. Refrigerants have much lower temperatures and much higher heat transfer rates than water. In this comparative study of using R-134a or water as a cooling fluid in the condenser of a SPP, steam enters the shell side of a single-pass horizontal condenser and the condensate is collected at the bottom. Cooling fluid, “water or R-134a”, is fed into the tubes. The results of the analytical study indicated higher condensation rates and heat transfer for R-134a than water. Moreover, the exergetic and exergy efficiency analysis revealed that R-134a has higher values than water, which increase the power plant thermal efficiency and reduce the condenser size.
The Effect of Coulomb Friction in Foil Structure on the Static and Dynamic Performance of Bump Foil Journal Bearings
Authors: Xu Fangcheng , Zhang Guanghui , Sun Yi , Liu Zhansheng , Wang Yu , Xu Ning
Published: September 2014

The Coulomb friction model for foil structure of bump foil journal bearing was developed by using finite element mothod. Through changing friction coefficient between top foil and bump foil, bump foil and bearing housing, the stiffness of foil strucure, the Coulomb friction model and linear spring model in earlier literatures were compared under various load distributions, and the effects of Coulomb friction on stiffness of bump foil was studied. The developed structural model was also integrated into foil bearing prediction code to evaluate the effects of the friction on the bearing static and dynamic performance.
Experimental Evaluation of the Effectiveness of Online Water-Washing in Gas Turbine Compressors
Authors: Brun Klaus , Foiles William C. , Grimley Terrence A. , Kurz Rainer
Published: September 2014

An investigation of the effectiveness of online combustion turbine axial compressor washing using various purity grade waters and commercial washing detergents was performed. For this project, blade surface fouling dirt was obtained from gas turbine axial compressor blades installed at various field sites. The dirt was analyzed to determine the composition and consistency of typical blade surface fouling materials. A representative dirt formula and blade coating procedure was developed so that comparative tests could be performed using various cleaning fluids. Dirt coated blades were installed in a wind tunnel capable of simulating compressor operating conditions. A spray nozzle upstream of the blade test section was used for washing blades with five different test liquids to determine the effectiveness or advantages of any liquid. Once this testing was completed, a similar test setup was then utilized to inject a mixture of formulated fouling dirt and the various online cleaning liquids upstream of the blade into the wind tunnel to assess redeposit characteristics. The effect of high-purity water versus regular water on fouling dirt was also studied in separate residue experiments. Results indicate that spraying cleaning fluid into a flowing air stream is a viable means of cleaning a compressor blade. Each of the fluids was able to clean the test blade at both low and high air velocities and at different blade incident angles. Within the parameters/fluids tested, the results indicate that:

1. The blade cleaning is primarily a mechanical function and does not depend on the type of fluid used for cleaning. The results showed that most of the cleaning occurs shortly after the cleaning fluid is introduced into the flow stream.

2. Dirt removed from the blades may redeposit in other areas as the cleaning fluid is evaporated. Redeposit occurred in flow recirculation zones during the cleaning tests, and heated flow tests demonstrated dirt deposit in the presence of a cleaning fluid. In addition, the type of fluid used for cleaning has no effect on the redeposit characteristics of the dirt.

3. Blade erosion was not found to be a significant issue for the short durations that online water-washing was performed. However, uncontrolled water-washing (or overspray) for extended periods of time did result in measureable leading and trailing edge blade erosions.
Dynamical Analysis on Circumferential Rod Fastening Rotor System in Heavy-Duty Gas Turbine
Authors: Li Huiguang , Yang Lihua , Wang Weimin , Zhao Shiquan , Liu Xueyun , Qi Xiaobing , Yu Lie , Zhou Jian
Published: September 2014

Circumferential rod fastening rotor system is widely used in heavy-duty gas turbines because of its advantages such as light weight, good cooling, easy assembly and so on. The force, torque or load between components in this type of rotor system must be transmitted depending on the contact interfaces. In this paper, the normal and tangential interface contact stiffness of rough surface are obtained according to the relationship between force and deformation of the finite element contact model which can reflect the surface topography. Then, the dynamic analysis method is presented and two models are built to analyze the dynamic performance of composite rod fastening rotor system. The effects of interface contact stiffness on the natural frequencies and unbalance responses of rotor system are studied. The results illustrate that the normal contact stiffness of rough surface linearly increase when the normal load rise, but the tangential contact stiffness decrease with the tangential pressure increasing. Furthermore, the contact stiffness has important effects on the natural frequencies and unbalance responses of rotor system. With the growth of contact stiffness, the natural frequencies increase, while the unbalance response amplitudes of rotor system decrease.
Kinetics of Oxidation of a 100% Gas-to-Liquid Synthetic Jet Fuel and a Mixture GTL/1-Hexanol in a Jet-Stirred Reactor: Experimental and Modeling Study
Authors: Mzé-Ahmed Amir , Dagaut Philippe , Dayma Guillaume , Diévart Pascal
Published: September 2014

Research activities on the combustion of synthetic jet fuels and bio-derived jet fuels have increased notably over the last 10 years in order to solve the challenging reduction of dependence of air transportation on petroleum. Within the European Community’s Seventh Framework Programme, the combustion of a 100% GtL from Shell and a 80/20% vol. GtL/1-hexanol blend were studied in a jet-stirred reactor (JSR). This synthetic GtL fuel mainly contains n-alkanes, iso-alkanes, and cyclo-alkanes. We studied the oxidation of these alternatives jet fuels under the same conditions (temperature, 550–1150 K; pressure, 10 bar; equivalence ratio, 0.5–2; initial fuel concentration, 1000 ppm). For simulating the oxidation kinetics of these fuels we used a new surrogate mixture consisting of n-dodecane, 3-methylheptane, n-propylcyclohexane, and 1-hexanol. A detailed chemical kinetic reaction mechanism was developed and validated by comparison with the experimental results obtained in a jet-stirred reactor. The current model was also tested for the autoignition of the GtL fuel under shock tubes conditions (φ = 1 and P = 20 atm) using data from the literature. Kinetic computations involving reaction paths analyses and sensitivity analyses were used to interpret the results. The general findings are that the GTL and GTL/hexanol blend have very similar reactivity to Jet A-1, which is important since GTL is a drop-in fuel that should have similar performance to the Jet A-1 baseline and 1-hexanol should not significantly affect the reactivity if it is to be used as an additive.
Casing Pressure Measurements and Numerical Simulations of a 1.5 Stage Axial Compressor: Tip Leakage Flow and Rotating Instability
Authors: Wang Hao , Wu Yadong , Ouyang Hua , Tian Jie , Du Zhaohui
Published: September 2014

Experimental and numerical investigations on the unsteady casing flow field in a one-and-half stage low speed axial compressor have been carried out. By using fast response pressure transducers instrumented on the rotor casing, the pressure time series were acquired at different operation points from throttle wide open to near-stall operation point. The pseudo-spatial pressure contours, phase-locked averaged and root-mean-square pressure contours and power spectrums of unsteady pressure signal have been achieved. The CFD simulations were conducted to help understanding the features of tip leakage vortex.

The rotating instability has been detected throughout an operation range from small flow rate point to near stall point. The frequency characteristic of rotating instability according flow rate was discussed. Based on the pattern of RIF varying with flow rate, the developing process of rotating instability according to flow rate could be divided into two stages, referred as early-developing stage and fully-developed stage. By analyzing the correlation between rotating instability and casing flow field, it was discovered that the origination and development of rotating instability was closely related to the fluctuation induced by tip leakage vortex.