bluuebunny/crossref_metadata_2025 huggingface dataset:
From nature to the laboratory: the impact of founder effects on adaptation
Authors: Santos J. , Pascual M. , Simões P. , Fragata I. , Lima M. , Kellen B. , Santos M. , Marques A. , Rose M. R. , Matos M.
Published: October 2012

Most founding events entail a reduction in population size, which in turn leads to genetic drift effects that can deplete alleles. Besides reducing neutral genetic variability, founder effects can in principle shift additive genetic variance for phenotypes that underlie fitness. This could then lead to different rates of adaptation among populations that have undergone a population size bottleneck as well as an environmental change, even when these populations have a common evolutionary history. Thus, theory suggests that there should be an association between observable genetic variability for both neutral markers and phenotypes related to fitness. Here, we test this scenario by monitoring the early evolutionary dynamics of six laboratory foundations derived from founders taken from the same source natural population of Drosophila subobscura. Each foundation was in turn three‐fold replicated. During their first few generations, these six foundations showed an abrupt increase in their genetic differentiation, within and between foundations. The eighteen populations that were monitored also differed in their patterns of phenotypic adaptation according to their immediately ancestral founding sample. Differences in early genetic variability and in effective population size were found to predict differences in the rate of adaptation during the first 21 generations of laboratory evolution. We show that evolution in a novel environment is strongly contingent not only on the initial composition of a newly founded population but also on the stochastic changes that occur during the first generations of colonization. Such effects make laboratory populations poor guides to the evolutionary genetic properties of their ancestral wild populations.
Elevated expression of brain‐derived neurotrophic factor facilitates visual imprinting in chicks
Authors: Suzuki Keiko , Maekawa Fumihiko , Suzuki Shingo , Nakamori Tomoharu , Sugiyama Hayato , Kanamatsu Tomoyuki , Tanaka Kohichi , Ohki‐Hamazaki Hiroko
Published: October 2012

With the aim of elucidating the neural mechanisms of early learning, we studied the role of brain‐derived neurotrophic factor (BDNF) in visual imprinting in birds. The telencephalic neural circuit connecting the visual Wulst and intermediate medial mesopallium is critical for imprinting, and the core region of the hyperpallium densocellulare (HDCo), situated at the center of this circuit, has a key role in regulating the activity of the circuit. We found that the number of BDNF mRNA‐positive cells in the HDCo was elevated during the critical period, particularly at its onset, on the day of hatching (P0). After imprinting training on P1, BDNF mRNA‐positive cells in the HDCo increased in number, and tyrosine phosphorylation of TrkB was observed. BDNF infusion into the HDCo at P1 induced imprinting, even with a weak training protocol that does not normally induce imprinting. In contrast, K252a, an antagonist of Trk, inhibited imprinting. Injection of BDNF at P7, after the critical period, did not elicit imprinting. These results suggest that BDNF promotes the induction of imprinting through TrkB exclusively during the critical period.
Sleep/wake dependent changes in cortical glucose concentrations
Authors: Dash Michael B , Bellesi Michele , Tononi Giulio , Cirelli Chiara
Published: October 2012

Most of the energy in the brain comes from glucose and supports glutamatergic activity. The firing rate of cortical glutamatergic neurons, as well as cortical extracellular glutamate levels, increase with time spent awake and decline throughout non rapid eye movement sleep, raising the question whether glucose levels reflect behavioral state and sleep/wake history. Here chronic (2–3 days) electroencephalographic recordings in the rat cerebral cortex were coupled with fixed‐potential amperometry to monitor the extracellular concentration of glucose ([gluc]) on a second‐by‐second basis across the spontaneous sleep‐wake cycle and in response to 3 h of sleep deprivation. [Gluc] progressively increased during non rapid eye movement sleep and declined during rapid eye movement sleep, while during wake an early decline in [gluc] was followed by an increase 8–15 min after awakening. There was a significant time of day effect during the dark phase, when rats are mostly awake, with [gluc] being significantly lower during the last 3–4 h of the night relative to the first 3–4 h. Moreover, the duration of the early phase of [gluc] decline during wake was longer after prolonged wake than after consolidated sleep. Thus, the sleep/wake history may affect the levels of glucose available to the brain upon awakening.
Calpain inhibitor attenuated optic nerve damage in acute optic neuritis in rats
Authors: Das Arabinda , Guyton M. Kelly , Smith Amena , Wallace Gerald , McDowell Misty L. , Matzelle Denise D. , Ray Swapan K. , Banik Naren L.
Published: October 2012

Optic neuritis (ON), which is an acute inflammatory autoimmune demyelinating disease of the central nervous system (CNS), often occurs in multiple sclerosis (MS). ON is an early diagnostic sign in most MS patients caused by damage to the optic nerve leading to visual dysfunction. Various features of both MS and ON can be studied following induction of experimental autoimmune encephalomyelitis (EAE), an animal model of MS, in Lewis rats. Inflammation and cell death in the optic nerve, with subsequent damage to the retinal ganglion cells in the retina, are thought to correlate with visual dysfunction. Thus, characterizing the pathophysiological changes that lead to visual dysfunction in EAE animals may help develop novel targets for therapeutic intervention. We treated EAE animals with and without the calpain inhibitor calpeptin (CP). Our studies demonstrated that the Ca2+‐activated neutral protease calpain was upregulated in the optic nerve following induction of EAE at the onset of clinical signs (OCS) of the disease, and these changes were attenuated following treatment with CP. These reductions correlated with decreases in inflammation (cytokines, iNOS, COX‐2, and NF‐κB), and microgliosis (i.e. activated microglia). We observed that calpain inhibition reduced astrogliosis (reactive astroglia) and expression of aquaporin 4 (AQP4). The balance of Th1/Th2 cytokine production and also expression of the Th1‐related CCR5 and CXCR3 chemokine receptors influence many pathological processes and play both causative and protective roles in neuron damage. Our data indicated that CP suppressed cytokine imbalances. Also, Bax:Bcl‐2 ratio, production of tBid, PARP‐1, expression and activities of calpain and caspases, and internucleosomal DNA fragmentation were attenuated after treatment with CP. Our results demonstrated that CP decreased demyelination [loss of myelin basic protein (MBP)] and axonal damage [increase in dephosphorylated neurofilament protein (de‐NFP)], and also promoted intracellular neuroprotective pathways in optic nerve in EAE rats. Thus, these data suggest that calpain is involved in inflammatory as well as in neurodegenerative aspects of the disease and may be a promising target for treating ON in EAE and MS.
Nesfatin‐1, corticotropin‐releasing hormone, thyrotropin‐releasing hormone, and neuronal histamine interact in the hypothalamus to regulate feeding behavior
Authors: Gotoh Koro , Masaki Takayuki , Chiba Seiichi , Ando Hisae , Shimasaki Takanobu , Mitsutomi Kimihiko , Fujiwara Kansuke , Katsuragi Isao , Kakuma Tetsuya , Sakata Toshiie , Yoshimatsu Hironobu
Published: October 2012

Nesfatin‐1, corticotropin‐releasing hormone (CRH), thyrotropin‐releasing hormone (TRH), and hypothalamic neuronal histamine act as anorexigenics in the hypothalamus. We examined interactions among nesfatin‐1, CRH, TRH, and histamine in the regulation of feeding behavior in rodents. We investigated whether the anorectic effect of nesfatin‐1, α‐fluoromethyl histidine (FMH; a specific suicide inhibitor of histidine decarboxylase that depletes hypothalamic neuronal histamine), a CRH antagonist, or anti‐TRH antibody affects the anorectic effect of nesfatin‐1, whether nesfatin‐1 increases CRH and TRH contents and histamine turnover in the hypothalamus, and whether histamine increases nesfatin‐1 content in the hypothalamus. We also investigated whether nesfatin‐1 decreases food intake in mice with targeted disruption of the histamine H1 receptor (H1KO mice) and if the H1 receptor (H1‐R) co‐localizes in nesfatin‐1 neurons. Nesfatin‐1‐suppressed feeding was partially attenuated in rats administered with FMH, a CRH antagonist, or anti‐TRH antibody, and in H1KO mice. Nesfatin‐1 increased CRH and TRH levels and histamine turnover, whereas histamine increased nesfatin‐1 in the hypothalamus. Immunohistochemical analysis revealed H1‐R expression on nesfatin‐1 neurons in the paraventricular nucleus of the hypothalamus. These results indicate that CRH, TRH, and hypothalamic neuronal histamine mediate the suppressive effects of nesfatin‐1 on feeding behavior.
A Comparison of Adaptive Choice‐Based Conjoint and Choice‐Based Conjoint to Determine Key Choice Attributes of Sour Cream with Limited Sample Size
Authors: Jervis S.M. , Ennis J.M. , Drake M.A.
Published: October 2012

Adaptive choice‐based conjoint (ACBC) analysis is a technique that uses choice data and incorporates it into an adaptive interviewing experience. ACBC analysis has been suggested to provide more accurate information at the individual level, which can lead to better predictions even when using smaller sample sizes. A comparison of a traditional choice‐based conjoint (CBC) survey and an ACBC survey was undertaken to compare the overall utility scores and importance values of attributes determined by both techniques using sour cream as the subject. A CBC and an ACBC survey were conducted. More respondents participated in the CBC (n = 777) survey than in the ACBC version (n = 250). Respondents to the ACBC version were from the same pool of respondents to the CBC version. A random sample of 250 respondents from the CBC survey was also analyzed. Results were analyzed by overall utility scores, importance values, landscape segmentation analysis and cluster analysis via latent class. The ACBC and CBC results were similar in overall utility scores for all attributes with similar respondent clusters. Both techniques revealed fat content as the most important attribute, followed by price and followed by brand. The CBC result for 250 respondents overestimated the importance of brand. The ACBC utility scores were not as distinct as CBC results in all categories; however, the direction of the mean utility scores was the same in all categories. Overall, ACBC and CBC revealed similar outcomes for different sour cream product types when price was excluded; however, the CBC results differentiated products to a greater extent than ACBC with the same sample size considered.

Practical Applications

Conjoint analysis is a research technique widely utilized across multiple industries as a way of determining the utility of a product or a product feature. Adaptive choice‐based conjoint (ACBC) is a new form of conjoint analysis. Because of the format of ACBC studies, respondents may be more engaged in the survey‐taking experience and provide answers that are more in‐line with their actual choice behavior. Because of this, ACBC studies may reveal more accurate responses for specific attributes such as brand and/or price. ACBC studies may also require fewer respondents, which is advantageous when the audience is highly selective, or if money and/or time is a concern.
Ronidazole pharmacokinetics in cats following delivery of a delayed‐release guar gum formulation
Authors: Papich M. G. , LeVine D. N. , Gookin J. L. , Davidson G. S. , Stagner W. C. , Hayes R. B.
Published: October 2012

Ronidazole (RDZ) is the only known effective treatment for feline diarrhea caused byTritrichomonas foetus. This study aimed to develop guar gum‐coated colon‐targeted tablets ofRDZand to determine the pharmacokinetics of this delayed‐release formulation in cats. Guar gum‐coated tablets were administered orally once to five healthy cats (mean dose 32.3 mg/kg). The tablets were then administered once daily for 5 days to four cats (mean dose 34.5 mg/kg), and absorption studies repeated on day 5. Plasma was collected and analyzed forRDZconcentration, and pharmacokinetic noncompartmental and deconvolution analysis were performed on the data. There was negligibleRDZrelease until after 6 h, and a delayed peak plasma concentration (meanCmax28.9 μg/mL) at approximately 14.5 h, which coincides with colonic arrival in cats. Maximum input rate (mg/kg per hour) occurred between 6 and 16 h. This delayed release of ronidazole from guar gum‐coated tablets indicates that release ofRDZmay be delayed to deliver the medication to a targeted area of the intestine. Repeated dosing with guar gum tablets to steady‐state did not inhibit drug bioavailability or alter the pharmacokinetics. Such targetedRDZdrug delivery may provide improved efficacy and reduce adverse effects in cats.
Intrahepatic mRNA levels of SOCS1 and SOCS3 are associated with cirrhosis but do not predict virological response to therapy in chronic hepatitis C
Authors: Pascarella Stéphanie , Clément Sophie , Dill Michael T. , Conzelmann Stéphanie , Lagging Martin , Missale Gabriele , Neumann Avidan U. , Pawlotsky Jean‐Michel , Zeuzem Stefan , Rubbia‐Brandt Laura , Bochud Pierre‐Yves , Negro Francesco
Published: October 2012

Background

Antiviral treatment of chronic hepatitis C is not invariably successful, costly and associated with serious side‐effects, and therefore should be indicated only when the chances of benefitting patients exceed the potential risks. The suppressor of cytokine signalling (SOCS) family members have been suggested to affect the rate of virological response to therapy, but the published evidence is conflicting.

Methods

We measured the intrahepatic SOCS1, SOCS3 and SOCS7 mRNA levels in 107 chronic hepatitis C patients and assessed their clinical and histological correlates with the virological response to therapy and with some factors known for affecting treatment outcome.

Results

By multivariate analysis, SOCS1, SOCS3 and SOCS7 mRNA levels were not associated with rapid or sustained virological response. Similarly, no association was found between the levels of any intrahepatic SOCS mRNA and those of the homeostasis model assessment of insulin resistance. Conversely, SOCS1 (OR 2.185, 95% CI 1.223–3.906, P=0.0083) and SOCS3 (OR 40.601, 95% CI 2.357–699.25, P=0.0108) mRNA level (but not SOCS7), together with age (OR 1.156, 95% CI 1.049–1.275, P=0.0036), were independently associated with cirrhosis.

Conclusions

Intrahepatic SOCS1, SOCS3 and SOCS7 mRNA levels do not predict virological response to therapy in chronic hepatitis C. The association between SOCS1, SOCS3 and cirrhosis warrants further study.
Special features ofRADSequencing data: implications for genotyping
Authors: Davey John W. , Cezard Timothée , Fuentes‐Utrilla Pablo , Eland Cathlene , Gharbi Karim , Blaxter Mark L.
Published: October 2012

Restriction site‐associated DNA Sequencing (RAD‐Seq) is an economical and efficient method forSNPdiscovery and genotyping. As with other sequencing‐by‐synthesis methods,RAD‐Seq produces stochastic count data and requires sensitive analysis to develop or genotype markers accurately. We show that there are several sources of bias specific toRAD‐Seq that are not explicitly addressed by current genotyping tools, namely restriction fragment bias, restriction site heterozygosity andPCR GCcontent bias. We explore the performance of existing analysis tools given these biases and discuss approaches to limiting or handling biases inRAD‐Seq data. While these biases need to be taken seriously, we believeRADloci affected by them can be excluded or processed with relative ease in most cases and that mostRADloci will be accurately genotyped by existing tools.
Landscape genetics of a top neotropical predator
Authors: Pérez‐Espona S. , McLeod J. E. , Franks N. R.
Published: October 2012

Habitat loss and fragmentation as a consequence of human activities is a worldwide phenomenon and one of the major threats to global biodiversity. Habitat loss and fragmentation is particularly a concern in the biodiverse tropics, where deforestation is occurring at unprecedented rates. Although insects are one of the most diverse and functionally important groups in tropical ecosystems, the quantitative effect of landscape features on their gene flow remains unknown. Here, we used a robust landscape genetics approach to quantify the effect of ten landscape features (deforestation, mature forests, other forest types, the River Chagres, streams, stream banks, roads, sea, lakes and swamps) and interactions between them, on the gene flow of a neotropical forest keystone species, the army ant Eciton burchellii. The influence of landscape on E. burchellii's gene flow reflected the different dispersal capability of its sexes; aerial for males and pedestrian for females, and the different depths of population history inferred from microsatellites and mitochondrial DNA. In contrast to the gene flow‐facilitating effect of mature forests, deforested areas were found to be strong barriers for E. burchellii's gene flow. Other forest types were found to be gene flow facilitators but only when interacting with mature secondary forests, therefore indicating the importance of mature forests for the survival of E. burchelii and its associate species. The River Chagres was identified as a major historical gene flow barrier for E. burchellii, suggesting that an important loss of connectivity may occur because of large artificial waterways such as the Panama Canal.
The effect ofRADallele dropout on the estimation of genetic variation within and between populations
Authors: Gautier Mathieu , Gharbi Karim , Cezard Timothee , Foucaud Julien , Kerdelhué Carole , Pudlo Pierre , Cornuet Jean‐Marie , Estoup Arnaud
Published: October 2012

Inexpensive short‐read sequencing technologies applied to reduced representation genomes is revolutionizing genetic research, especially population genetics analysis, by allowing the genotyping of massive numbers of single‐nucleotide polymorphisms (SNP) for large numbers of individuals and populations. Restriction site–associatedDNA(RAD) sequencing is a recent technique based on the characterization of genomic regions flanking restriction sites. One of its potential drawbacks is the presence of polymorphism within the restriction site, which makes it impossible to observe the associatedSNPallele (i.e. allele dropout,ADO). To investigate the effect ofADOon genetic variation estimated fromRADmarkers, we first mathematically derived measures of the effect ofADOon allele frequencies as a function of different parameters within a single population. We then usedRADdata sets simulated using a coalescence model to investigate the magnitude of biases induced byADOon the estimation of expected heterozygosity andFSTunder a simple demographic model of divergence between two populations. We found thatADOtends to overestimate genetic variation both within and between populations. Assuming a mutation rate per nucleotide between 10−9and 10−8, this bias remained low for most studied combinations of divergence time and effective population size, except for large effective population sizes. AveragingFSTvalues over multipleSNPs, for example, by sliding window analysis, did not correctADObiases. We briefly discuss possible solutions to filter the most problematic cases ofADOusing read coverage to detect markers with a large excess of null alleles.
Multiple capacitors for natural genetic variation in Drosophila melanogaster
Authors: Takahashi Kazuo H.
Published: October 2012

Cryptic genetic variation (CGV) or a standing genetic variation that is not ordinarily expressed as a phenotype is released when the robustness of organisms is impaired under environmental or genetic perturbations. Evolutionary capacitors modulate the amount of genetic variation exposed to natural selection and hidden cryptically; they have a fundamental effect on the evolvability of traits on evolutionary timescales. In this study, I have demonstrated the effects of multiple genomic regions of Drosophila melanogaster on CGV in wing shape. I examined the effects of 61 genomic deficiencies on quantitative and qualitative natural genetic variation in the wing shape of D. melanogaster. I have identified 10 genomic deficiencies that do not encompass a known candidate evolutionary capacitor, Hsp90, exposing natural CGV differently depending on the location of the deficiencies in the genome. Furthermore, five genomic deficiencies uncovered qualitative CGV in wing morphology. These findings suggest that CGV in wing shape of wild‐type D. melanogaster is regulated by multiple capacitors with divergent functions. Future analysis of genes encompassed by these genomic regions would help elucidate novel capacitor genes and better understand the general features of capacitors regarding natural genetic variation.
A Case of Recalcitrant Epidermolysis Bullosa Acquisita Responsive to Rituximab Therapy
Authors: McKinley Sophia K. , Huang Jennifer T. , Tan Jennifer , Kroshinsky Daniela , Gellis Stephen
Published: October 2012

Epidermolysis bullosa acquisita (EBA) is an autoimmune blistering disorder that occurs infrequently in children. Although typically associated with a good prognosis in children, there are rare cases that are refractory to treatment with conventional immunosuppressive therapy. Rituximab, an anti‐CD20 monoclonal antibody, has been reported to be effective in the adult form of EBA. We report a case of a child with severe and recalcitrant EBA exhibiting a sustained response to treatment with rituximab.
Subacute Cutaneous Lupus Erythematosus Presenting in Childhood: A Case Report and Review of the Literature
Authors: Berry Tammy , Walsh Erica , Berry Ryan , DeSantis Emily , Smidt Aimee C.
Published: October 2012

A 2‐year‐old African American, Hispanic boy presented with well‐defined, violaceous, annular dermal plaques without scale over the upper extremities, face, lower extremities, and buttocks. The clinical presentation and laboratory studies were consistent with a diagnosis of subacute cutaneous lupus erythematous (SCLE). SCLE presenting in childhood is exceedingly rare, with only eight cases previously reported. It is important to clinically differentiate SCLE from other eruptions more common to children, such as atopic dermatitis, urticarial drug eruptions, and psoriasis vulgaris, because progression to systemic lupus erythematous (SLE) may occur. SLE needs to be closely followed. We present the first case (to our knowledge) of SCLE in a child of African American or Hispanic descent and provide a table of other documented pediatric presentations of SCLE for comparison.
Varicella Precipitating Febrile Ulceronecrotic Mucha‐Habermann Disease
Authors: Hervás Juan A. , Martín‐Santiago Ana , Hervás Daniel , Gómez Cristina , Dueñas Joaquín , Reina Jordi
Published: October 2012

We report a 9‐year‐old boy with skin lesions clinically and histologically compatible with pityriasis lichenoides et varioliformis acuta that evolved to the severe variant febrile ulceronecrotic Mucha‐Habermann disease and finally to pityriasis lichenoides chronica. Varicella‐zoster virus (VZV) was isolated in culture medium from the skin lesions and serum serology was positive for VZV. This is the first time that a virus has been isolated in culture in this condition.
Focal Preauricular Dermal Dysplasia in a Newborn
Authors: Coughlin Carrie C. , Dunbar Scott W. , Bayliss Susan J. , Berk David R.
Published: October 2012

We report a case of focal preauricular dermal dysplasia in an 18‐day‐old healthy girl. We discuss the classification of focal preauricular dermal dysplasia within the spectrum of focal facial dermal dysplasia and aplasia cutis congenita.
Onychomycosis in Immunosuppressed Children Receiving Chemotherapy
Authors: García‐Romero Maria Teresa , Aguilar Enrique L. , Arenas Roberto
Published: October 2012

Onychomycosis in children has a low incidence worldwide; certain conditions such as immunosuppression have been described as risk factors for it. We studied 72 children receiving chemotherapy for different neoplasms to determine the frequency of onychomycosis. Only one patient had white superficial onychomycosis from Trichophyton rubrum, a frequency of 1.3%, not different from that reported in healthy patients.
Human papillomavirus distribution in invasive cervical carcinoma in sub‐Saharan Africa: could HIV explain the differences?
Authors: Ndiaye Cathy , Alemany Laia , Ndiaye Nafissatou , Kamaté Bakarou , Diop Yankhoba , Odida Michael , Banjo Kunbi , Tous Sara , Klaustermeier Jo Ellen , Clavero Omar , Castellsagué Xavier , Xavier Bosch F. , Trottier Helen , de Sanjosé Silvia
Published: October 2012

Objectives  To describe human papillomavirus (HPV) distribution in invasive cervical carcinoma (ICC) from Mali and Senegal and to compare type‐specific relative contribution among sub‐Saharan African (SSA) countries.

Methods  A multicentric study was conducted to collect paraffin‐embedded blocks of ICC. Polymerase chain reaction, DNA enzyme immunoassay and line probe assay were performed for HPV detection and genotyping. Data from SSA (Mozambique, Nigeria and Uganda) and 35 other countries were compared.

Results  One hundred and sixty‐four ICC cases from Mali and Senegal were tested from which 138 were positive (adjusted prevalence = 86.8%; 95% CI = 79.7–91.7%). HPV16 and HPV18 accounted for 57.2% of infections and HPV45 for 16.7%. In SSA countries, HPV16 was less frequent than in the rest of the world (49.4%vs. 62.6%; P < 0.0001) but HPV18 and HPV45 were two times more frequent (19.3%vs. 9.4%; P < 0.0001 and 10.3%vs. 5.6%; P < 0.0001, respectively). There was an ecological correlation between HIV prevalence and the increase of HPV18 and the decrease of HPV45 in ICC in SSA (P = 0.037 for both).

Conclusion  HPV16/18/45 accounted for two‐thirds of the HPV types found in invasive cervical cancer in Mali and Senegal. Our results suggest that HIV may play a role in the underlying HPV18 and HPV45 contribution to cervical cancer, but further studies are needed to confirm this correlation.
Development and validation of a ‘universal’ HPLC method for pyrethroid quantification in long‐lasting insecticidal mosquito nets for malaria control and prevention
Authors: Jenkins David W. , Hensens Arno , Lloyd Jacob , Payne Michael , Cizmarik Peter , Hamel Steve
Published: October 2012

Objectives

To outline the development and validation of a universal method for quantifying deltamethrin, permethrin and alpha‐cypermethrin levels in a variety of long‐lasting insecticidal mosquito nets.

Methods

Using the HPLC conditions found in the CIPAC method for deltamethrin quantification, the method is based on a simple extraction technique for sample preparation (heating in isooctane at approximately 100 °C for 15 min). The method was validated for linearity, specificity, accuracy, precision, insecticide stability to extraction conditions and required extraction time for insecticide removal.

Results

The method was found valid for insecticide quantifications for various types of nets, namely for deltamethrin coated on polyester nets, deltamethrin incorporated into polyethylene nets, permethrin incorporated into polyethylene nets, alpha‐cypermethrin coated on polyester nets and alpha‐cypermethrin incorporated into polyethylene nets.

Conclusions

This method will provide a more simplified approach to testing a variety of nets (different types of fibre) containing deltamethrin, permethrin or alpha‐cypermethrin.
Electro‐gene‐transfer as a new tool for cancer immunotherapy in animals
Authors: Impellizeri J. A. , Ciliberto G. , Aurisicchio L.
Published: October 2012

The concept of vaccines based on the direct inoculation of plasmid DNA gained initial proof‐of‐concept in small rodent species. Further development was hampered by the difficulty to confirm immunogenicity and efficacy in large animal species and, most importantly, in human clinical trials. These negative findings led to the search of complementary technologies which, in combination with intradermal or intramuscular plasmid DNA injection would result in more robust delivery, decreased interindividual variability, clear evidence of clinical efficacy and which would eventually lead to market approval of new vaccine products. The use of high‐pressure, needleless devices as an enhancing tool for plasmid DNA delivery led to recent approval by USDA of Oncept™, a therapeutic cancer vaccine directed against tyrosinase for the therapy of melanoma in dogs. An alternative approach to improve plasmid DNA delivery is electro‐gene‐transfer (EGT). In this article, we briefly review the principles of DNA‐EGT and the evidences for efficacy of a telomerase reverse transcriptase vaccine in a dog clinical trial, and provide perspectives for the use of this technology for broader applications in pet animals.
Assessing potential germination period of weeds with base temperatures and base water potentials
Authors: GUILLEMIN J‐P , GARDARIN A , GRANGER S , REIBEL C , MUNIER‐JOLAIN N , COLBACH N
Published: October 2012

Seed germination partly depends on both base temperature (Tb) and base water potential (Ψb), which currently are known only for a small number of species. Laboratory experiments were conducted to estimate these parameters for 14 weed species using the ‘x‐intercept’ method. Tb and Ψb (°C and MPa) for the 14 weed species were as follows: Amaranthus retroflexus (8.9 and −0.95), Ambrosia artemisiifolia (3.6 and −1.28), Avena fatua (2.2 and −1.02), Capsella bursa‐pastoris (4.5 and −0.95), Chenopodium album (5.9 and −0.80), Echinochloa crus‐galli (6.2 and −1.19), Geranium dissectum (0.6 and −3.31), Matricaria perforata (2.0 and −0.75), Picris echioides (5.2 and −0.79), Polygonum lapathifolium (5.8 and −1.55), Senecio vulgaris (2.5 and −1.23), Setaria pumila (8.6 and −0.75), Solanum nigrum (11.6 and −0.89) and Veronica hederifolia (0.2 and −1.67). The two parameters were used to determine potential germination times during expected non‐dormancy periods for three contrasting climatic years in Dijon, France. The number of potential germination days varied little among the tested climatic years, but substantially among species, ranging from 95 ± 9 days for V. hederifolia to 280 ± 7 days for M. perforata. These results may be of value for development of predictive growth models and understanding times when weed control may be most feasible.
Experimental and Numerical Investigation of Flow Field and Downstream Surface Temperatures of Cylindrical and Diffuser Shaped Film Cooling Holes1
Authors: Kampe Tilman auf dem , Völker Stefan , Sämel Torsten , Heneka Christian , Ladisch Helge , Schulz Achmed , Bauer Hans-Jörg
Published: October 2012

An experimental and numerical study of the flow field and the downstream film cooling performance of cylindrical and diffuser shaped cooling holes is presented. The measurements were conducted on a flat plate with a single cooling hole with coolant ejected from a plenum. The flow field was investigated by means of 3D-PIV as well as 3D-LDV measurements, the downstream film cooling effectiveness by means of infrared thermography. Cylindrical and diffuser holes without lateral inclination have been examined, varying blowing ratio and density ratio as well as freestream turbulence levels. 3D-CFD simulations have been performed and validated along with the experimental efforts. The results, presented in terms of contour plots of the three normalized velocity components as well as adiabatic film cooling effectiveness, clearly show the flow structure of the film cooling jets and the differences brought about by the variation of hole geometry and flow parameters. The quantitative agreement between experiment and CFD was reasonable, with better agreement for cylindrical holes than for diffuser holes.
Influence of the Different Design Parameters to the Centrifugal Compressor Tip Clearance Loss
Authors: Turunen-Saaresti Teemu , Jaatinen Ahti
Published: October 2012

In this paper the effect of the tip clearance was studied with six different centrifugal compressors and data available in literature. The changes in the overall performance of the compressor stage were examined. The aim was to study the influence of the different design parameters to the tip clearance loss. It was evident by the previous studies that the sensitivity of the centrifugal compressor to the tip clearance loss varies with different designs. However, for the designer it is important to know the effect of the tip clearance loss in order to initially evaluate the quality of different designs. Analysis of the data demonstrated that no clear correlation between the sensitivity of the tip clearance loss and the specific speed, the diffusion ratio, the blade number and the ratio of blade heights exists.
Identifying Turbulent Spots in Transitional Boundary Layers
Authors: Rehill Brendan , Walsh Ed J. , Brandt Luca , Schlatter Philipp , Zaki Tamer A. , McEligot Donald M.
Published: October 2012

An artificial turbulent spot is simulated in a zero free-stream turbulence base flow and a base flow with organized streaks. Six identification methods are used in order to isolate the turbulent spot from the surrounding nonturbulent fluid. These are (i) instantaneous wall-normal velocity v, (ii) instantaneous spanwise velocity w, (iii) instantaneous turbulent dissipation, (iv) λ2 criterion, (v) Q criterion, and (vi) gradient of the finite time Lyapunov exponent. All methods are effective in isolating the turbulent spot from the streaks. The robustness of each technique is determined from the sensitivity of the maximum spot dimensions to changes in threshold level. The Q criterion shows the least sensitivity for the zero free-stream turbulence case and the instantaneous turbulent dissipation technique is least sensitive in the organized streaks case. For both cases the v technique was the most sensitive to changes in threshold level.
Heat Transfer Enhancement in a Rectangular (AR = 3:1) Channel With V-Shaped Dimples
Authors: Neil Jordan C. , Wright Lesley M.
Published: October 2012

An alternative to ribs for internal heat transfer enhancement of gas turbine airfoils is dimpled depressions. Relative to ribs, dimples incur a reduced pressure drop, which can increase the overall thermal performance of the channel. This experimental investigation measures detailed Nusselt number ratio distributions obtained from an array of V-shaped dimples (δ/D = 0.30). Although the V-shaped dimple array is derived from a traditional hemispherical dimple array, the V-shaped dimples are arranged in an in-line pattern. The resulting spacing of the V-shaped dimples is 3.2D in both the streamwise and spanwise directions. A single wide wall of a rectangular channel (AR = 3:1) is lined with V-shaped dimples. The channel Reynolds number ranges from 10,000–40,000. Detailed Nusselt number ratios are obtained using both a transient liquid crystal technique and a newly developed transient temperature sensitive paint (TSP) technique. Therefore, the TSP technique is not only validated against a baseline geometry (smooth channel), but it is also validated against a more established technique. Measurements indicate that the proposed V-shaped dimple design is a promising alternative to traditional ribs or hemispherical dimples. At lower Reynolds numbers, the V-shaped dimples display heat transfer and friction behavior similar to traditional dimples. However, as the Reynolds number increases to 30,000 and 40,000, secondary flows developed in the V-shaped concavities further enhance the heat transfer from the dimpled surface (similar to angled and V-shaped rib induced secondary flows). This additional enhancement is obtained with only a marginal increase in the pressure drop. Therefore, as the Reynolds number within the channel increases, the thermal performance also increases. While this trend has been confirmed with both the transient TSP and liquid crystal techniques, TSP is shown to have limited capabilities when acquiring highly resolved detailed heat transfer coefficient distributions.
Film-Cooled Trailing Edge Measurements: 3D Velocity and Scalar Field
Authors: Benson Michael , Laskowski Gregory , Elkins Chris , Eaton John K.
Published: October 2012

Aircraft turbine blade trailing edges commonly are cooled by blowing air through pressure-side cutback slots. The surface effectiveness is governed by the rate of mixing of the coolant with the mainstream, which is typically much faster than predicted by CFD models. Three-dimensional velocity and coolant concentration fields were measured in and around a cutback slot using a simple uncambered airfoil with a realistic trailing edge cooling geometry at a Reynolds number of 110,000 based on airfoil chord length, which is lower than practical engines but still in the turbulent regime. The results were obtained using magnetic resonance imaging (MRI) techniques in a water flow apparatus. Magnetic resonance concentration (MRC) scans measured the concentration distribution with a spatial resolution of 0.5 mm3 (compared to a slot height of 5 mm) and an uncertainty near 5%. Magnetic resonance velocimetry (MRV) was used to acquire 3D, three-component mean velocity measurements with a resolution of 1.0 mm3. Coupled concentration and velocity measurements were used to identify flow structures contributing to the rapid mixing, including longitudinal vortices and separation bubbles. Velocity measurements at several locations were compared with an unsteady RANS model. Concentration measurements extrapolated to the surface provided film cooling effectiveness and showed that the longitudinal vortices decreased effectiveness near the lands and reduced the average film cooling effectiveness.
Experimental Comparison of DBD Plasma Actuators for Low Reynolds Number Separation Control
Authors: Marks Christopher R. , Sondergaard Rolf , Wolff Mitch , Anthony Rich
Published: October 2012

This paper presents experimental work comparing several Dielectric Barrier Discharge (DBD) plasma actuator configurations for low Reynolds number separation control. Actuators studied here are being investigated for use in a closed loop separation control system. The plasma actuators were fabricated in the U.S. Air Force Research Laboratory Propulsion Directorate’s thin film laboratory and applied to a low Reynolds number airfoil that exhibits similar suction surface behavior to those observed on Low Pressure (LP) Turbine blades. In addition to typical asymmetric arrangements producing downstream jets, one electrode configurations was designed to produce an array of off axis jets, and one produced a spanwise array of linear vertical jets in order to generate vorticity and improved boundary layer to freestream mixing. The actuators were installed on an airfoil and their performance compared by flow visualization, surface stress sensitive film (S3F), and drag measurements. The experimental data provides a clear picture of the potential utility of each design. Experiments were carried out at four Reynolds numbers, 1.4 × 105, 1.0 × 105, 6.0 × 104, and 5.0 × 104 at a-1.5 deg angle of attack. Data was taken at the AFRL Propulsion Directorate’s Low Speed Wind Tunnel (LSWT) facility.
Development of a Fused Deposition Modeling System for Low Melting Temperature Metal Alloys
Authors: Mireles Jorge , Kim Ho-Chan , Hwan Lee In , Espalin David , Medina Francisco , MacDonald Eric , Wicker Ryan
Published: October 2012

This research focused on extending the applications of fused deposition modeling (FDM) by extrusion and deposition of low melting temperature metal alloys to create three-dimensional metal structures and single-layer contacts which may prove useful for electronic interconnects. Six commercially available low melting temperature solder alloys (Bi36Pb32Sn31Ag1, Bi58Sn42, Sn63Pb37, Sn50Pb50, Sn60Bi40, Sn96.5Ag3.5) were tested for the creation of a fused deposition modeling for metals (FDMm) system with special attention given to Sn–Bi solders. An existing FDM 3000 was used and two alloys were successfully extruded through the system's extrusion head. Deposition was achieved through specific modifications to system toolpath commands and a comparison of solders with eutectic and non-eutectic compositions is discussed. The modifications demonstrate the ability to extrude simple single-layer solder lines with varying thicknesses, including sharp 90 deg angles and smooth curved lines and showing the possibility of using this system for printed circuit board applications in which various connections need to be processed. Deposition parameters altered for extrusion and the deposition results of low melting temperature metal alloys are introduced.
A Model for Highly Strained DNA Compressed Inside a Protein Cavity
Authors: Hirsh Andrew D. , Lillian Todd D. , Lionberger Troy A. , Taranova Maryna , Andricioaei Ioan , Perkins N. C.
Published: October 2012

Deoxyribonucleic acid (DNA) is a long and flexible biopolymer that contains genetic information. Building upon the discovery of the iconic double helix over 50 years ago, subsequent studies have emphasized how its biological function is related to the mechanical properties of the molecule. A remarkable system which highlights the role of DNA bending and twisting is the packing and ejection of DNA into and from viral capsids. A recent 3D reconstruction of bacteriophage φ29 reveals a novel toroidal structure of highly bent/twisted DNA contained in a small cavity below the viral capsid. Here, we extend an elastic rod model for DNA to enable simulation of the toroid as it is compacted and subsequently ejected from a small volume. We compute biologically-relevant forces required to form the toroid and predict ejection times of several nanoseconds.
Modeling of a Flexible Instrument to Study its Sliding Behavior Inside a Curved Endoscope
Authors: Khatait Jitendra P. , Brouwer Dannis M. , Aarts Ronald G. K. M. , Herder Just L.
Published: October 2012

Flexible instruments are increasingly used to carry out surgical procedures. The instrument tip is remotely controlled by the surgeon. The flexibility of the instrument and the friction inside the curved endoscope jeopardize the control of the instrument tip. Characterization of the surgical instrument behavior enables the control of the tip motion. A flexible multibody modeling approach was used to study the sliding behavior of the instrument inside a curved endoscope. The surgical instrument was modeled as a series of interconnected planar beam elements. The curved endoscope was modeled as a rigid curved tube. A static friction-based contact model was implemented. The simulations were carried out both for the insertion of the flexible instrument and for fine manipulation. A computer program (SPACAR) was used for the modeling and simulation. The simulation result shows the stick-slip behavior and the motion hysteresis because of the friction. The coefficient of friction has a large influence on the motion hysteresis, whereas the bending rigidity of the instrument has little influence.
A Continuum Based Three-Dimensional Modeling of Wind Turbine Blades
Authors: Bayoumy Ahmed H. , Nada Ayman A. , Megahed Said M.
Published: October 2012

Accurate modeling of large wind turbine blades is an extremely challenging problem. This is due to their tremendous geometric complexity and the turbulent and unpredictable conditions in which they operate. In this paper, a continuum based three dimensional finite element model of an elastic wind turbine blade is derived using the absolute nodal coordinates formulation (ANCF). This formulation is very suitable for modeling of large-deformation, large-rotation structures like wind turbine blades. An efficient model of six thin plate elements is proposed for such blades with non-uniform, and twisted nature. Furthermore, a mapping procedure to construct the ANCF model of NACA (National Advisory Committee for Aeronautics) wind turbine blades airfoils is established to mesh the geometry of a real turbine blade. The complex shape of such blades is approximated using an absolute nodal coordinate thin plate element, to take the blades tapering and twist into account. Three numerical examples are presented to show the transient response of the wind turbine blades due to gravitational/aerodynamics forces. The simulation results are compared with those obtained using ANSYS code with a good agreement.
Calculation of Human Femoral Vein Wall Parameters In Vivo From Clinical Data for Specific Patient
Authors: Herrera Blas , Fortuny Gerard , Marimón Francesc
Published: October 2012

A common problem in the elaboration of biomechanical models is determining the properties and characteristics (measures) of the physical behavior of in vivo tissues in the human body. Correct estimates must be made of the tissue's physical properties and its surroundings. We suggest a method to compute the constitutive modeling of venous tissue, for every specific patient, from clinically registered ultrasounds images. The vein is modeled as a hyperelastic, incompressible, thin-walled cylinder and the membrane stresses are computed using strain energy. The approach is based on a strain-energy function suggested by Holzapfel capturing the characteristic nonlinear anisotropic responses of femoral veins with its collagen fibers.
Computational Fluid Dynamics Evaluation of the Cross-Limb Stent Graft Configuration for Endovascular Aneurysm Repair
Authors: Shek Tina L. T. , Tse Leonard W. , Nabovati Aydin , Amon Cristina H.
Published: October 2012

The technique of crossing the limbs of bifurcated modular stent grafts for endovascular aneurysm repair (EVAR) is often employed in the face of splayed aortic bifurcations to facilitate cannulation and prevent device kinking. However, little has been reported about the implications of cross-limb EVAR, especially in comparison to conventional EVAR. Previous computational fluid dynamics studies of conventional EVAR grafts have mostly utilized simplified planar stent graft geometries. We herein examined the differences between conventional and cross-limb EVAR by comparing their hemodynamic flow fields (i.e., in the “direct” and “cross” configurations, respectively). We also added a “planar” configuration, which is commonly found in the literature, to identify how well this configuration compares to out-of-plane stent graft configurations from a hemodynamic perspective. A representative patient’s cross-limb stent graft geometry was segmented using computed tomography imaging in Mimics software. The cross-limb graft geometry was used to build its direct and planar counterparts in SolidWorks. Physiologic velocity and mass flow boundary conditions and blood properties were implemented for steady-state and pulsatile transient simulations in ANSYS CFX. Displacement forces, wall shear stress (WSS), and oscillatory shear index (OSI) were all comparable between the direct and cross configurations, whereas the planar geometry yielded very different predictions of hemodynamics compared to the out-of-plane stent graft configurations, particularly for displacement forces. This single-patient study suggests that the short-term hemodynamics involved in crossing the limbs is as safe as conventional EVAR. Higher helicity and improved WSS distribution of the cross-limb configuration suggest improved flow-related thrombosis resistance in the short term. However, there may be long-term fatigue implications to stent graft use in the cross configuration when compared to the direct configuration.