bluuebunny/crossref_metadata_2025 huggingface dataset:
Noninvasive Follow-Up of Simian Immunodeficiency Virus Infection in Wild-Living Nonhabituated Western Lowland Gorillas in Cameroon
Authors: Etienne Lucie , Locatelli Sabrina , Ayouba Ahidjo , Esteban Amandine , Butel Christelle , Liegeois Florian , Aghokeng Avelin , Delaporte Eric , Mpoudi Ngole Eitel , Peeters Martine
Published: June 2012

Simian immunodeficiency viruses infecting western lowland gorillas (SIVgor) are closely related to HIV-1 and are most likely the ancestors of HIV-1 groups O and P. At present, limited data are available on genetic diversity, transmission, viral evolution, and pathogenicity of SIVgor in its natural host. Between 2004 and 2011, 961 putative gorilla fecal samples were collected at the Campo Ma'an National Park, Cameroon. Among them, 16% cross-reacted with HIV-1 antibodies, corresponding to at least 34 infected gorillas. Combining host genotyping and field data, we identified four social groups composed of 7 to 15 individuals each, with SIV rates ranging from 13% to 29%. Eleven SIVgor-infected gorillas were sampled multiple times; two most likely seroconverted during the study period, showing that SIVgor continues to spread. Phylogenetic analysis of partial
env
and
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sequences revealed cocirculation of closely related and divergent strains among gorillas from the same social group, indicating SIVgor transmissions within and between groups. Parental links could be inferred for some gorillas infected with closely related strains, suggesting vertical transmission, but horizontal transmission by sexual or aggressive behavior was also suspected. Intrahost molecular evolution in one gorilla over a 5-year period showed viral adaptations characteristic of escape mutants, i.e., V1V2 loop elongation and an increased number of glycosylation sites. Here we show for the first time the feasibility of noninvasive monitoring of nonhabituated gorillas to study SIVgor infection over time at both the individual and population levels. This approach can also be applied more generally to study other pathogens in wildlife.
The C11R Gene, Which Encodes the Vaccinia Virus Growth Factor, Is Partially Responsible for MVA-Induced NF-κB and ERK2 Activation
Authors: Martin Stefani , Harris Daniel T. , Shisler Joanna
Published: June 2012

MVA is an attenuated strain of vaccinia virus (VACV) that is a popular vaccine vector. MVA infection activates NF-κB. For 293T cells, it is known that MVA early gene expression activates extracellular signal-regulated kinase 2 (ERK2), resulting in NF-κB activation. However, other viral and cellular mechanisms responsible for this event are ill defined. The data presented here show that the epidermal growth factor receptor (EGFR) is at least one apical trigger in this pathway: ERK2 and NF-κB activation was diminished when MVA infections occurred in cells devoid of the EGFR (CHO K1 cells) or in the presence of a drug that inhibits EGFR activation (AG1478) in 293T cells. The expression of dominant negative Ras or Raf proteins still permitted NF-κB activation, suggesting that a nonclassical EGFR-based signal transduction pathway triggered ERK2–NF-κB activation. C11R is an early gene present in MVA and other orthopoxviruses. It encodes the soluble, secreted vaccinia virus growth factor (VGF), a protein that binds to and stimulates the EGFR. Here it was observed that NF-κB was activated in 293T cells transfected with a plasmid encoding the C11R gene. Silencing by small interfering RNA (siRNA) or deletion of the C11R gene (MVAΔC11R) reduced both MVA-induced ERK2 and NF-κB activation in 293T cells or the keratinocyte line Hacat, suggesting that this mechanism of MVA-induced NF-κB activation may be common for several cell types.
An Acupuncture Needle Remaining in a Lung for 17 years: Case Study and Review
Authors: Lewek Pawel , Lewek Joanna , Kardas Przemyslaw
Published: June 2012

The case of a 67-year-old patient with an acupuncture needle remaining in his left lung is described. This foreign body was a remnant of a procedure performed by a doctor 17 years previously for osteoarthritic back pain. On the basis of this case, a review was performed of literature available in the PubMed database dealing with acupuncture needles remaining in a patient's body. A total of 25 articles were found. The articles describe needles found in the bladder, shoulder girdle, spinal cord, right ventricle, L5 nerve root, medulla oblongata, skin, carpal tunnel, nuchal and occipital area, calf and paraspinal muscle. Migration of needle fragments to the liver, pancreas, stomach, colon, breast, kidney, muscles, and spinal cord has been reported in the literature. In cases where patients were operated on, the needles were removed without subsequent complications and the patients recovered fully.
Joint lavage in the treatment of ovine septic pedal arthritis
Authors: Lovatt Fiona
Published: June 2012

The form of treatment usually recommended for sheep with septic pedal arthritis is amputation of the digit, but farmers may be reluctant to follow this course of action. This article discusses an alternative, joint lavage, which can be undertaken on farm without specialised equipment. It describes the technique as well as discussing the outcome of treatment.
Radiological manifestations of metastasis to the ovary
Authors: Willmott Fredric , Allouni Kader Abdel , Rockall Andrea
Published: June 2012

MRI is an effective tool for detection of ovarian neoplastic lesions. However, there are no highly specific radiological features that differentiate primary from metastatic ovarian masses. Histological diagnosis preoperatively is not always possible as there is a risk of disseminating an otherwise early stage primary ovarian cancer. The preoperative diagnosis of an ovarian lesion is therefore heavily dependent on the radiological features. The radiologist must rely on a combination of knowing the natural history of any known primary cancer, together with the radiological features such as bilaterality, mucinous appearance, pseudomyxoma as well as the clinical progress of the primary tumour in order to evaluate and predict the likelihood of metastatic disease. Even if a non-ovarian primary cancer is known, an ovarian mass cannot always be assumed to be a secondary lesion. Some tumours, such as BRAC-positive breast cancer, are known to have a high rate of concomitant primary ovarian cancer. Conversely, other tumours, such as gastric and appendiceal cancer, are known to have a high rate of ovarian metastatic disease. However, histology remains the only true way to determine an ovarian metastasis from a primary lesion.
Sex-ratio variation versus interplant distances in the regulation of pollen deposition and seed production in dioecious Cirsium arvense (Asteraceae)1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.
Authors: Van Drunen Wendy E. , Dorken Marcel E.
Published: June 2012

Pollination success in dioecious plants is expected to be regulated by the ratio of female:male plants and the distances between plants of each sex. These factors have received considerable attention in studies of dioecious and other gender dimorphic plants, yet their effects have rarely been jointly considered. We documented sex ratios in 26 populations of Cirsium arvense (L.) Scop. (creeping thistle), a widely distributed clonal dioecious plant, and show that population sex ratios are generally female biased (∼60% of shoots were female, and 15 of 26 populations were female biased). We found clear evidence for a negative association between pollen loads and distances between females and males within populations. In contrast, and in spite of broad variation in sex ratios among populations (range: 0.11–0.99 female), we found no relationship between sex ratios and pollen receipt by females. However, both sex ratios and interplant distances were associated with female seed production: seed production declined with distances between females and males and increased with the proportion of male shoots. Our data suggest that female plants of C. arvense might often be pollen limited and that distances between individual females and males drive pollen limitation more strongly than the overall frequency of males within sites.
Histological and anatomical responses in avocado, Persea americana, induced by the vascular wilt pathogen, Raffaelea lauricola
Authors: Inch Sharon , Ploetz Randy , Held Benjamin , Blanchette Robert
Published: June 2012

Raffaelea lauricola causes laurel wilt of avocado, Persea americana. Host × pathogen interactions were examined with light and scanning electron microscopy. The susceptible avocado cultivar ‘Simmonds’ was inoculated and examined 5 cm above the inoculation site 3, 7, 14, 21, and 42 days after inoculation (dai). No external symptoms were observed at 3 and 7 dai, and there were no anatomical differences when compared with the mock-inoculated plants. By 14 dai, external symptoms were present and dark discoloration had developed in sapwood. Tylose development increased significantly by 14 dai, and was positivity correlated with disease severity (P < 0.05). By 14 dai, gels formed in xylem vessels, fibers, and adjacent parenchyma cells; they were associated with xylem blockage and composed of phenols, pectin, and lipids, as suggested by, respectively, toluidine blue O, ruthenium red, and Sudan III stains. With a chitin-specific stain, fluorescein-conjugated wheat germ agglutinin, infrequent mycelia, and conidia of R. lauricola were visualized within xylem lumena and fibers, regardless of sample date. Understanding how avocado responds to the presence of this pathogen could assist the development of laurel wilt-resistant avocado genotypes and inform efforts to manage this disease with other measures.
Sex-ratio variation and the function of staminodes inAralia nudicaulis1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.
Authors: Nicholls Emony I.E. , Dorken Marcel E.
Published: June 2012

Aralia nudicaulis L. is a clonal dioecious herb common to forested ecosystems in eastern North America. Across 15 sites, the frequency of female ramets ranged between 5% and 95%. This variation was used to examine hypotheses involving the life history and pollination biology of A. nudicaulis. Because female reproductive function is thought to incur greater resource costs than male function, we predicted that female ramets should (i) be more common where resources (and light in particular) are more abundant and (ii) have lower rates of survival than male ramets. However, there was (i) no significant association between light availability (measured as canopy closure) and female frequencies across sites and (ii) ramet ages were skewed towards older ages for females, not males. Female A. nudicaulis produce staminodes that render female inflorescences visually similar to male inflorescences. We experimentally manipulated the presence–absence of staminodes and found that pollen receipt by females without staminodes was substantially lower than for plants with intact staminodes. Finally, pollinators tend to prefer visiting male over female flowers. We were interested in evaluating whether such preferences might scale up to the population level, with higher pollinator abundances at male-dominated sites. However, we instead found a strong positive association between pollinator abundances and female frequencies. Although there is unlikely to be a causal relationship between them, the identification of a common variable underlying variation in female frequencies and pollinator abundances might reveal key insights into the factors regulating the life history and pollination of forest understory plants.
A phylogenetic analysis of trait convergence in the spring flora1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.
Authors: Hensel Lisa E. , Sargent Risa D.
Published: June 2012

In temperate deciduous forests, spring flowering plants exhibit remarkable similarity in a number of characteristics, including reproductive, vegetative, and ecological traits. The apparent convergence of floral traits, especially corolla colour, among spring flowering species has been well documented, but remains poorly understood. Here we review adaptive hypotheses and predictions that have been proposed to explain the apparent correlation between spring flowering and a suite of traits. We investigated the correlation between flowering phenology (i.e., spring or nonspring) and several key traits using phylogenetic comparative methods. Through this analysis we were able to confirm the existence of a correlation for five of the six traits examined. Specifically, spring flowering is shown to have evolved in a correlated fashion with reproductive schedule (perennial vs. annual), light corolla colour, fruit type, growth form, and forest strata layer. In general, our survey determined that spring flowering species are perennial, have light coloured corollas, a herbaceous growth form, and tend to occupy the understory of the forest. These results are discussed in light of the reviewed adaptive hypotheses and the spring pollination environment.
Pollen diversity collected by honey bees in the vicinity of Vaccinium spp. crops and its importance for colony development1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.
Authors: Girard Mélissa , Chagnon Madeleine , Fournier Valérie
Published: June 2012

Access to a rich diversity of flowering plants is very important for the development of honey bee colonies introduced in crops for pollination. The aim of this observational study was to determine the impact of surrounding pollen diversity on the health of honey bee colonies introduced in lowbush blueberries ( Vaccinium angustifolium Ait.) in June and cranberries ( Vaccinium macrocarpon Ait.) in July. The results suggest that monocultures of lowbush blueberries are not suitable for optimal brood rearing. In the blueberry environments we studied, the dominant pollen collected by honey bees were Alnus Mill. spp. and Taraxacum officinale F.H. Wigg., which are deficient in some essential amino acids. Significant reduction of brood rearing during honey bees’ stay in blueberry monocultures in June may, therefore, be explained by nutritional deficiencies. In July, the polliniferous flora in the vicinity of cranberry monocultures was poorer but of better nutritional quality. Pollen analysis allowed the identification of Brassicaceae, Trifolium L. spp., and V. macrocarpon as the three dominant taxa collected by honey bees during this period. The complete lists of plant taxa foraged by honey bees for pollen during the pollination of lowbush blueberries and cranberries are provided.
Systemic range shift lags among a pollinator species assemblage following rapid climate change1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.
Authors: Bedford Felicity E. , Whittaker Robert J. , Kerr Jeremy T.
Published: June 2012

Contemporary climate change is driving widespread geographical range shifts among many species. If species are tracking changing climate successfully, then leading populations should experience similar climatic conditions through time as new populations establish beyond historical range margins. Here, we investigate geographical range shifts relative to changing climatic conditions among a particularly well-sampled assemblage of butterflies in Canada. We assembled observations of 81 species and measured their latitudinal displacement between two periods: 1960–1975 (a period of little climate change) and 1990–2005 (a period with large climate change). We find an unexpected trend for species’ northern borders to shift progressively less relative to increasing minimum winter temperatures in northern Canada. This study demonstrates a novel, systemic latitudinal gradient in lags among a large species assemblage in responses to recent climate change. Even among the most mobile species and without anthropogenic barriers to dispersal, these pollinators have been unable to extend their ranges as fast as required to keep pace with climate change.
Pollen-ovule ratios in seven species ofVaccinium(Ericaceae) and stamen structure inVaccinium myrtilloidesandVaccinium vitis-idaea1This article is part of a Special Issue entitled “Pollination biology research in Canada: Perspectives on a mutualism at different scales”.
Authors: Stephens Danielle T. , Levesque Danielle E. , Davis Arthur R.
Published: June 2012

Pollen-ovule (P/O) ratios were determined for five Vaccinium species (Ericaceae) native to eastern Canada (Nova Scotia: V. angustifolium, V. boreale, V. caespitosum, V. corymbosum, V. uliginosum), one in western Canada (Saskatchewan: V. myrtilloides), and one (V. vitis-idaea) from both provinces. Pollen, released at maturity as tetrads, was converted to total pollen grains per flower to yield P/O ratios ranging from 238 (V. caespitosum) to 2008 (V. vitis-idaea), but 736 for the latter in Saskatchewan. These P/O ratios are indicative of facultative autogamy to facultative xenogamy. Additionally, the structure of mature stamens and pollen tetrads was studied in V. myrtilloides and V. vitis-idaea. Each anther was functionally bilocular; had a single-cell thickness (i.e., epidermis) with regularly occurring papillae; lacked an endothecium; and possessed two distal, hollow tubules each terminating in a pore. Overall pollen grain viability was 76%–97% (V. myrtilloides) and 51%–93% (V. vitis-idaea), with about 20% of tetrads having only 1–3 grains viable, and 12% and 27% of tetrads entirely nonviable in V. myrtilloides and V. vitis-idaea, respectively. Pollen tetrads occasionally were connected by a sticky substance resembling pollenkitt, but viscin threads were absent. One instance of precocious (in situ) germination of tetrads was recorded within anthers of V. myrtilloides.
Discussion of “New zircon shock phenomena and their use for dating and reconstruction of large impact structures revealed by electron nanobeam (EBSD, CL, EDS) and isotopic U–Pb and (U–Th)/He analysis of the Vredefort dome”1Appears in Canadian Journal of Earth Sciences, 2011, 48(2): 117–139 [doi: dx.doi.org/10.1139/e11-011].
Authors: Rajesh H.M. , Knoper M.W.
Published: June 2012

Spodumene pegmatites occur in the southeastern sector of the 2.02 Ga Vredefort impact structure in South Africa. Moser et al. (published in 2011) presented an isotope dilution – thermal ionization mass spectrometry (ID–TIMS) age of 1136 ± 47 Ma for these spodumene pegmatites. This discussion questions the reliability of this age. Field relations indicate that the spodumene pegmatites are not affected by the structural fabric that affected the host amphibolites. The crosscutting impact-related veins of pseudotachylitic breccia clearly argues a preimpact age for the spodumene pegmatites. The high-uranium content of one of the two zircons used by Moser et al. to obtain the age is correlated to the ∼1.1 Ga Pb-loss event, widely observed in different rocks within the Vredefort impact structure.
40Ar–39Ar ages for detrital white mica in Meguma terrane, Nova Scotia, Canada: implications for provenance of the Goldenville and Halifax groups
Authors: Reynolds P.H. , White C.E. , Barr S.M. , Muir C.M.
Published: June 2012

Single-grain 40Ar/39Ar ages are reported for detrital white mica, along with conventional step-heating data for whole rocks, from low-grade metasandstone samples from the Goldenville, Halifax, and Rockville Notch groups in the Meguma terrane of southern Nova Scotia. The majority (166) of single grains from 11 samples yielded ages between ca. 615 and 350 Ma, and the remaining 12 grains yielded ages between ca. 1900 and 870 Ma. The late Neoproterozoic–Paleozoic age distributions are consistent with derivation of sediments from the rapidly uplifted flanks of an active rift, where partial to complete resetting of white mica ages occurred at ca. 520–500 Ma, preceding sediment deposition. The ca. 615 Ma ages may be relics of the original detrital white mica that existed in the source rocks prior to the rifting event. Ages from the Upper Silurian White Rock Formation appear to reflect this same ca. 520–500 Ma event, suggesting that sediments in the White Rock Formation were recycled from the Goldenville and Halifax groups. The older Precambrian ages are inferred to represent white mica in the source region, likely Amazonia. The whole-rock age spectra are discordant, with pronounced age gradients and no well-defined age plateaus. Initial gas released from five of the samples at low laboratory extraction temperatures (ca. 450–500 °C) yielded ages of ca. 260–300 Ma, not seen in the single-grain data, whereas gas released at the highest extraction temperatures yielded ages in the range ca. 510–530 Ma, possibly reflecting the principal result obtained from the single-grain data.
Obducted nappe sequence in the San Juan Islands – northwest Cascades thrust system, Washington and British Columbia
Authors: Brown E.H.
Published: June 2012

The San Juan Islands – northwest Cascades thrust system in Washington and British Columbia is composed of previously accreted terranes now assembled as four broadly defined composite nappes stacked on a continental footwall of Wrangellia and the Coast Plutonic Complex. Emplacement ages of the nappe sequence are interpreted from zircon ages, field relations, and lithlogies, to young upward. The basal nappe was emplaced prior to early Turonian time (∼93 Ma), indicated by the occurrence of age-distinctive zircons from this nappe in the Sidney Island Formation of the Nanaimo Group. The emplacement age of the highest nappe in the thrust system postdates 87 Ma detrital zircons within the nappe. The nappes bear high-pressure – low-temperature (HP–LT) mineral assemblages indicative of deep burial in a thrust wedge; however, several features indicate that metamorphism occurred prior to nappe assembly: metamorphic discontinuities at nappe boundaries, absence of HP–LT assemblages in the footwall to the nappe pile, and absence of significant unroofing detritus in the Nanaimo Group. A synorogenic relationship of the thrust system to the Nanaimo Group is evident from mutually overlapping ages and by conglomerates of Nanaimo affinity that lie within the nappe pile. From the foregoing relations, and broader Cordilleran geology, the tectonic history of the nappe terranes is interpreted to involve initial accretion and subduction-zone metamorphism south of the present locality, uplift and exhumation, orogen-parallel northward transport of the nappes as part of a forearc sliver, and finally obduction at the present site over the truncated south end of Wrangellia and the Coast Plutonic Complex.
Seismic force demand on ductile reinforced concrete shear walls subjected to western North American ground motions: Part 2 — new capacity design methods
Authors: Boivin Yannick , Paultre Patrick
Published: June 2012

This paper proposes for the Canadian Standards Association (CSA) standard A23.3 new capacity design methods, accounting for higher mode amplification effects, for determining, for a single plastic hinge design, capacity design envelopes for flexural and shear strength design of regular ductile reinforced concrete cantilever walls used as seismic force resisting system for multistorey buildings. The derivation of these methods is based on the outcomes from a review on various capacity design methods proposed in the current literature and recommended by design codes and from the extensive parametric study presented in the companion paper. A discussion on the limitations of the proposed methods and on their applicability to various wall systems is presented.
Mechanistic–empirical damage analysis and impacts of reduced tire pressure on thaw weakened flexible pavements using the AI and MEPDG models
Authors: Kavanagh Leonnie , Shalaby Ahmed
Published: June 2012

A damage analysis was conducted on a spring weight restricted flexible pavement to quantify the effects of reduced tire pressure on pavement life and to compare the damage predictions from the Asphalt Institute (AI) and the Mechanistic Empirical Pavement Design Guide (MEPDG) models. The models were used to predict the number of repetitions to fatigue and rutting failure at three maximum loads and at high and low tire pressures. Based on the results, the AI and MEPDG predictions were statistically different for both fatigue cracking and rutting damage, based on the t-test at 95% confidence limits. The AI model predicted 31% lower fatigue damage than the MEPDG, but 56% higher rutting damage. However, both models produced similar trends in predicting the relative effects of reduced tire pressure and load levels on pavement life. The methodology and results of the analysis are presented in this paper.
SOME VECTOR-VALUED SINGULAR AUTOMORPHIC FORMS ON U(2, 2) AND THEIR RESTRICTION TO Sp(1, 1)
Authors: YAMAUCHI ATSUO , NARITA HIRO-AKI
Published: June 2012

In this paper we provide a construction of theta series on the real symplectic group of signature (1,1) or the 4-dimensional hyperbolic space. We obtain these by considering the restriction of some vector-valued singular theta series on the unitary group of signature (2,2) to this indefinite symplectic group. Our (vector-valued) theta series are proved to have algebraic Fourier coefficients, and lead to a new explicit construction of automorphic forms generating quaternionic discrete series representations and automorphic functions on the hyperbolic space.
THE HALF-TWISTED SPLICE OPERATION ON REDUCED KNOT PROJECTIONS
Authors: ITO NOBORU , SHIMIZU AYAKA
Published: June 2012

We show that any nontrivial reduced knot projection can be obtained from a trefoil projection by a finite sequence of half-twisted splice operations and their inverses such that the result of each step in the sequence is reduced.
A UNIFYING APPROACH TO FRACTIONAL LÉVY PROCESSES
Authors: ENGELKE SEBASTIAN , WOERNER JEANNETTE H. C.
Published: June 2012

Starting from the moving average representation of fractional Brownian motion, there are two different approaches to constructing fractional Lévy processes in the literature. Applying L2-integration theory, one can keep the same moving average kernel and replace the driving Brownian motion by a pure jump Lévy process with finite second moments. Alternatively, in the framework of alpha-stable random measures, the Brownian motion is replaced by an alpha-stable Lévy process and the exponent in the kernel is reparametrized by H - 1/α. We now provide a unified approach taking kernels of the form [Formula: see text], where γ can be chosen according to the existing moments and the Blumenthal–Getoor index of the underlying Lévy process. These processes may exhibit both long and short range dependence. In addition we will examine further properties of the processes, e.g., regularity of the sample paths and the semimartingale property.
Elucidating mechanisms underlying altered renal autoregulation in diabetes
Authors: Takenaka Tsuneo , Inoue Tsutomu , Ohno Yoichi , Miyazaki Takashi , Nishiyama Akira , Ishii Naohito , Suzuki Hiromichi
Published: June 2012

Previous studies have reported that high-salt intake paradoxically activates tubuloglomerular feedback (TGF) in type 1 diabetes. Using Zucker lean (ZL) and diabetic fatty (ZDF) rats on normal and high-salt diets, renal hemodynamics and the renin-angiotensin system (RAS) were characterized. On normal salt diet, glomerular filtration rate (GFR) was higher in ZDF than ZL rats. Autoregulation of GFR was less efficient and lithium clearance was lower in ZDF rats than ZL rats. Salt load reduced GFR in ZDF rats with restoration of lithium clearance and partial improvement in autoregulatory index (AI). The administration of 8-cyclopentyl-1,3-dipropylxanthine, a selective adenosine-1 receptor antagonist to ZDF rats on a high-salt diet abolished the improvement of AI in GFR. However, this effect was seen by neitherCx40GAP27 norCx37,43GAP27, which inhibits connexin (Cx) 40 or Cx37. Renal ANG II was higher in ZDF than ZL rats on normal salt diet, but the difference was eliminated by a salt load. The present data provide the first demonstration for a salt paradox in type 2 diabetes and implicate that in addition to Cx alterations, an enhanced proximal reabsorption attenuates TGF, underlying glomerular hyperfiltration and RAS activation. These data suggest that a high-salt diet standardizes distal delivery in diabetes, suppressing the RAS, and improving GFR autoregulation and hyperfiltration through adenosine.
Pregnancy increases myometrial artery myogenic tone via NOS- or COX-independent mechanisms
Authors: Eckman Delrae M. , Gupta Ridhima , Rosenfeld Charles R. , Morgan Timothy M. , Charles Shelton M. , Mertz Heather , Moore Lorna G.
Published: June 2012

Myogenic tone (MT) is a primary modulator of blood flow in the resistance vasculature of the brain, kidney, skeletal muscle, and perhaps in other high-flow organs such as the pregnant uterus. MT is known to be regulated by endothelium-derived factors, including products of the nitric oxide synthase (NOS) and/or the cyclooxygenase (COX) pathways. We asked whether pregnancy influenced MT in myometrial arteries (MA), and if so, whether such an effect could be attributed to alterations in NOS and/or COX. MA (200–300 μm internal diameter, 2–3 mm length) were isolated from 10 nonpregnant and 12 pregnant women undergoing elective hysterectomy or cesarean section, respectively. In the absence of NOS and/or COX inhibition, pregnancy was associated with increased MT in endothelium-intact MA compared with MA from nonpregnant women ( P < 0.01). The increase in MT was not due to increased Ca2+ entry via voltage-dependent channels since both groups of MA exhibited similar levels of constriction when exposed to 50 mM KCl. NOS inhibition ( Nω-nitro-l-arginine methyl ester, l-NAME) or combined NOS/COX inhibition (l-NAME/indomethacin) increased MT in MA from pregnant women ( P = 0.001 and P = 0.042, respectively) but was without effect in arteries from nonpregnant women. Indomethacin alone was without effect on MT in MA from either nonpregnant or pregnant women. We concluded that MT increases in MA during human pregnancy and that this effect was partially opposed by enhanced NOS activity.
Lag Synchronization of Coupled Multidelay Systems
Authors: Qun Luo , Hai-Peng Peng , Ling-Yu Xu , Yi Xian Yang
Published: June 2012

Chaos synchronization is an active topic, and its possible applications have been studied extensively. In this paper we present an improved method for lag synchronization of chaotic systems with coupled multidelay. The Lyapunov theory is used to consider the sufficient condition for synchronization. The specific examples will demonstrate and verify the effectiveness of the proposed approach.
Implementation of an Innovative Method to Design Reflectarray Antennas
Authors: Tayebi Abdelhamid , Gómez Josefa , González Iván , Cátedra Felipe
Published: June 2012

A novel computed aided technique for designing reflectarray antennas is presented. The developed approach automatically generates the geometrical model of reflectarray antennas taking into account some input parameters, such as, the unit cell type and dimensions, frequency, focal length, periodicity, dielectric materials, and desired main beam radiating direction. The characteristics of the reflecting elements are selected considering the spatial phase delay at each unit cell to achieve a progressive phase shift. The implemented procedure also provides the phase characteristic of the unit element, which is rapidly computed by using a parallelized Moment Method (MoM) approach. The MoM is also used to obtain the radiation pattern of the full reflectarray antenna. In order to evaluate the new technique, a dual-interface prototype has been designed and simulated showing high-performance capability.
A Novel Method to Grow Vertically Aligned Silicon Nanowires on Si (111) and Their Optical Absorption
Authors: Ho Tzuen-Wei , Hong Franklin Chau-Nan
Published: June 2012

In this study we grew silicon nanowires (SiNWs) on Si (111) substrate by gold‐catalyzed vapor liquid solid (VLS) process using tetrachlorosilane (SiCl4) in a hot‐wall chemical vapor deposition reactor. SiNWs with 150–200 nm diameters were found to grow along the orientations of all 〈111〉 family, including the vertical and the inclined, on Si (111). The effects of various process conditions, including SiCl4 concentration, SiCl4 feeding temperature, H2 annealing, and ramp cooling, on the crystal quality and growth orientation of SiNWs, were studied to optimize the growth conditions. Furthermore, a novel method was developed to reliably grow vertically aligned SiNWs on Si (111) utilizing the principle of liquid phase epitaxy (LPE). A ramp‐cooling process was employed to slowly precipitate the epitaxial Si seeds on Si (111) after H2 annealing at 650°C. Then, after heating in SiCl4/H2 up to 850°C to grow SiNWs, almost 100% vertically aligned SiNWs could be achieved reproducibly. The high degree of vertical alignment of SiNWs is effective in reducing surface reflection of solar light with the reflectance decreasing with increasing the SiNWs length. The vertically aligned SiNWs have good potentials for solar cells and nano devices.
Detecting Cancer Outlier Genes with Potential Rearrangement Using Gene Expression Data and Biological Networks
Authors: Alshalalfa Mohammed , Bismar Tarek A. , Alhajj Reda
Published: June 2012

Gene alterations are a major component of the landscape of tumor genomes. To assess the significance of these alterations in the development of prostate cancer, it is necessary to identify these alterations and analyze them from systems biology perspective. Here, we present a new method (EigFusion) for predicting outlier genes with potential gene rearrangement. EigFusion demonstrated excellent performance in identifying outlier genes with potential rearrangement by testing it to synthetic and real data to evaluate performance. EigFusion was able to identify previously unrecognized genes such as FABP5 and KCNH8 and confirmed their association with primary and metastatic prostate samples while confirmed the metastatic specificity for other genes such as PAH, TOP2A, and SPINK1. We performed protein network based approaches to analyze the network context of potential rearranged genes. Functional gene rearrangement Modules are constructed by integrating functional protein networks. Rearranged genes showed to be highly connected to well-known altered genes in cancer such as AR, RB1, MYC, and BRCA1. Finally, using clinical outcome data of prostate cancer patients, potential rearranged genes demonstrated significant association with prostate cancer specific death.
Thimerosal-Derived Ethylmercury Is a Mitochondrial Toxin in Human Astrocytes: Possible Role of Fenton Chemistry in the Oxidation and Breakage of mtDNA
Authors: Sharpe Martyn A. , Livingston Andrew D. , Baskin David S.
Published: June 2012

Thimerosal generates ethylmercury in aqueous solution and is widely used as preservative. We have investigated the toxicology of Thimerosal in normal human astrocytes, paying particular attention to mitochondrial function and the generation of specific oxidants. We find that ethylmercury not only inhibits mitochondrial respiration leading to a drop in the steady state membrane potential, but also concurrent with these phenomena increases the formation of superoxide, hydrogen peroxide, and Fenton/Haber-Weiss generated hydroxyl radical. These oxidants increase the levels of cellular aldehyde/ketones. Additionally, we find a five-fold increase in the levels of oxidant damaged mitochondrial DNA bases and increases in the levels of mtDNA nicks and blunt-ended breaks. Highly damaged mitochondria are characterized by having very low membrane potentials, increased superoxide/hydrogen peroxide production, and extensively damaged mtDNA and proteins. These mitochondria appear to have undergone a permeability transition, an observation supported by the five-fold increase in Caspase-3 activity observed after Thimerosal treatment.
A New Positive Definite Expanded Mixed Finite Element Method for Parabolic Integrodifferential Equations
Authors: Liu Yang , Li Hong , Wang Jinfeng , Gao Wei
Published: June 2012

A new positive definite expanded mixed finite element method is proposed for parabolic partial integrodifferential equations. Compared to expanded mixed scheme, the new expanded mixed element system is symmetric positive definite and both the gradient equation and the flux equation are separated from its scalar unknown equation. The existence and uniqueness for semidiscrete scheme are proved and error estimates are derived for both semidiscrete and fully discrete schemes. Finally, some numerical results are provided to confirm our theoretical analysis.
Carbon Nanofiber Synthesis within 3-Dimensional Sintered Nickel Microfibrous Matrices: Optimization of Synthesis Conditions
Authors: Karwa Amogh N. , Davis Virginia A. , Tatarchuk Bruce J.
Published: June 2012

This study focuses on the process of optimization for carbon nanofiber synthesis at the exterior and the interior of 3-dimensional sintered nickel microfibrous networks. Synthesis of carbon nanofibers (CNF) by catalytic decomposition of acetylene (ethyne) was conducted at atmospheric pressure and short reaction times (10 min). Two factors evaluated during the study were (a) CNF quality (observed by SEM and Raman spectroscopy) and (b) rate of reaction (gravimetrically measured carbon yield). Independent optimization variables included redox faceting pretreatment of nickel, synthesis temperature, and gas composition. Faceting resulted in an 8-fold increase in the carbon yield compared to an untreated substrate. Synthesis with varying levels of hydrogen maximized the carbon yield (9.31 mg C/cm2catalyst). The quality of CNF was enhanced via a reduction in amorphous carbon that resulted from the addition of 20% ammonia. Optimized growth conditions that led to high rates of CNF deposition preferentially deposited this carbon at the exterior layer of the nickel microfibrous networks (570°C, 78% H2, 20% NH3, 2% C2H2, faceted Ni.). CNF growth within the 3-dimensional nickel networks was accomplished at the conditions selected to lower the gravimetric reaction rate (470°C, 10% H2, 88% N2, 2% C2H2, nonfaceted Ni).
A Relaxed Splitting Preconditioner for the Incompressible Navier‐Stokes Equations
Authors: Tan Ning-Bo , Huang Ting-Zhu , Hu Ze-Jun
Published: June 2012

A relaxed splitting preconditioner based on matrix splitting is introduced in this paper for linear systems of saddle point problem arising from numerical solution of the incompressible Navier‐Stokes equations. Spectral analysis of the preconditioned matrix is presented, and numerical experiments are carried out to illustrate the convergence behavior of the preconditioner for solving both steady and unsteady incompressible flow problems.
The Role of the Endothelium in HPS Pathogenesis and Potential Therapeutic Approaches
Authors: Gavrilovskaya Irina , Gorbunova Elena , Matthys Valery , Dalrymple Nadine , Mackow Erich
Published: June 2012

American hantaviruses cause a highly lethal acute pulmonary edema termed hantavirus pulmonary syndrome (HPS). Hantaviruses nonlytically infect endothelial cells and cause dramatic changes in barrier functions of the endothelium without disrupting the endothelium. Instead hantaviruses cause changes in the function of infected endothelial cells that normally regulate fluid barrier functions of capillaries. The endothelium of arteries, veins, and lymphatic vessels is unique and central to the function of vast pulmonary capillary beds, which regulate pulmonary fluid accumulation. The endothelium maintains vascular barrier functions through a complex series of redundant receptors and signaling pathways that serve to both permit fluid and immune cell efflux into tissues and restrict tissue edema. Infection of the endothelium provides several mechanisms for hantaviruses to alter capillary permeability but also defines potential therapeutic targets for regulating acute pulmonary edema and HPS disease. Here we discuss interactions of HPS causing hantaviruses with the endothelium, potential endothelial cell-directed permeability mechanisms, and therapeutic targeting of the endothelium as a means of reducing the severity of HPS disease.
Mixed Modeling with Whole Genome Data
Authors: Zhao Jing Hua , Luan Jian'an
Published: June 2012

Objective. We consider the need for a modeling framework for related individuals and various sources of variations. The relationships could either be among relatives in families or among unrelated individuals in a general population with cryptic relatedness; both could be refined or derived with whole genome data. As with variations they can include oliogogenes, polygenes, single nucleotide polymorphism (SNP), and covariates.Methods. We describe mixed models as a coherent theoretical framework to accommodate correlations for various types of outcomes in relation to many sources of variations. The framework also extends to consortium meta-analysis involving both population-based and family-based studies.Results. Through examples we show that the framework can be furnished with general statistical packages whose great advantage lies in simplicity and exibility to study both genetic and environmental effects. Areas which require further work are also indicated.Conclusion. Mixed models will play an important role in practical analysis of data on both families and unrelated individuals when whole genome information is available.
Worry Is Good for Breast Cancer Screening: A Study of Female Relatives from the Ontario Site of the Breast Cancer Family Registry
Authors: Zhang Li Rita , Chiarelli Anna M. , Glendon Gord , Mirea Lucia , Knight Julia A. , Andrulis Irene L. , Ritvo Paul
Published: June 2012

Background. Few prospective studies have examined associations between breast cancer worry and screening behaviours in women with elevated breast cancer risks based on family history.Methods. This study included 901 high familial risk women, aged 23–71 years, from the Ontario site of the Breast Cancer Family Registry. Self-reported breast screening behaviours at year-one followup were compared between women at low (N=305), medium (N=433), and high (N=163) levels of baseline breast cancer worry using logistic regression. Nonlinear relationships were assessed using likelihood ratio tests.Results. A significant non-linear inverted “U” relationship was observed between breast cancer worry and mammography screening (P=0.034) for all women, where women at either low or high worry levels were less likely than those at medium to have a screening mammogram. A similar significant non-linear inverted “U” relationship was also found among all women and women at low familial risk for worry and screening clinical breast examinations (CBEs).Conclusions. Medium levels of cancer worries predicted higher rates of screening mammography and CBE among high-risk women.
Neopterin as a Marker of Response to Antiviral Therapy in Hepatitis C Virus Patients
Authors: Oxenkrug Gregory F. , Requintina Pura J. , Mikolich Dennis L. , Ruthazer Robin , Viveiros Kathleen , Lee Hannah , Summergrad Paul
Published: June 2012

Predicting the efficacy of antiviral treatment of hepatitis C virus (HCV) is of importance for both patient well-being and health care expense. The expression of interferon-stimulated genes (IFN-SGs) in the liver was suggested as a marker of response to anti-viral therapy. IFN-SGs encode the guanosine triphosphate cyclohydrolase 1 (GTPCH), a rate-limiting enzyme of pteridines biosynthesis. Neopterin, a stable byproduct of GTPCH-catalyzed reaction, is used as a marker of interferon-induced GTPCH activation. We hypothesized that assessment of neopterin concentrations might predict the response to antiviral therapy. Neopterin concentrations were evaluated in 260 HCV patients treated by pegylated interferon combined with ribavirin. Mean and median pretreatment neopterin concentrations were lower in patients with sustained virological response than in nonresponders. The rate of response was twofold higher among patients with pretreatment neopterin levels <16 nmol/L than in patients with neopterin levels ≥16 nmol/L, even after controlling for HCV genotype status. Our study suggests that the pretreatment level of neopterin might be used in routine clinical practice as rapid and cost-effective marker to predict the response to antiviral therapy in HCV patients.
Detection of Canonical Hedgehog Signaling in Breast Cancer by 131-Iodine-Labeled Derivatives of the Sonic Hedgehog Protein
Authors: Sims-Mourtada Jennifer , Yang David , Tworowska Izabela , Larson Richard , Smith Daniel , Tsao Ning , Opdenaker Lynn , Mourtada Firas , Woodward Wendy
Published: June 2012

Activation of hedgehog (HH) pathway signaling is observed in many tumors. Due to a feedback loop, the HH receptor Patched (PTCH-1) is overexpressed in tumors with activated HH signaling. Therefore, we sought to radiolabel the PTCH-1 ligand sonic (SHH) for detection of cancer cells with canonical HH activity. Receptor binding of131I-SHH was increased in cell lines with high HH pathway activation. Our findings also show that PTCH-1 receptor expression is decreased upon treatment with HH signaling inhibitors, and receptor binding of131I-SHH is significantly decreased following treatment with cyclopamine.In vivoimaging and biodistribution studies revealed significant accumulation of131I-SHH within tumor tissue as compared to normal organs. Tumor-to-muscle ratios were approximately 8 : 1 at 5 hours, while tumor to blood and tumor to bone were 2 : 1 and 5 : 1, respectively. Significant uptake was also observed in liver and gastrointestinal tissue. These studies show that131I-SHH is capable ofin vivodetection of breast tumors with high HH signaling. We further demonstrate that the hedgehog receptor PTCH-1 is downregulated upon treatment with hedgehog inhibitors. Our data suggests that radiolabeled SHH derivatives may provide a method to determine response to SHH-targeted therapies.
Positive Solutions for Second‐Order Singular Semipositone Differential Equations Involving Stieltjes Integral Conditions
Authors: Jiang Jiqiang , Liu Lishan , Wu Yonghong
Published: June 2012

By means of the fixed point theory in cones, we investigate the existence of positive solutions for the following second‐order singular differential equations with a negatively perturbed term: −u′′(t) = λ[f(t, u(t)) − q(t)], 0 < t < 1, ,
where λ > 0 is a parameter; f : (0, 1) × (0, ∞) → [0, ∞)
is continuous; f(t, x)
may be singular at t = 0, t = 1, and x = 0, and the perturbed term q : (0, 1) → [0, +∞) is Lebesgue integrable and may have finitely many singularities in (0, 1), which implies that the nonlinear term may change sign.