bluuebunny/crossref_metadata_2025 huggingface dataset:
Moving least-squares finite element method
Authors: Musivand-Arzanfudi M , Hosseini-Toudeshky H
Published: September 2007

A new computational method here called moving least-squares finite element method (MLSFEM) is presented, in which the shape functions of the parametric elements are constructed using moving least-squares approximation. While preserving some excellent characteristics of the meshless methods such as elimination of the volumetric locking in near-incompressible materials and giving accurate strains and stresses near the boundaries of the problem, the computational time is decreased by constructing the meshless shape functions in the stage of creating parametric elements and then utilizing them for any new problem. Moreover, it is not necessary to have knowledge about the full details of the shape function generation method in future uses. The MLSFEM also eliminates another drawback of meshless methods associated with the lack of accordance between the integration cells and the problem boundaries. The method is described for two-dimensional problems, but it is extendable for three-dimensional problems too. The MLSFEM does not require the complex mesh generation. Excellent results can be obtained even using a simple mesh. A technique is also presented for isoparametric mapping which enables best possible mapping via a constrained optimization criterion. Several numerical examples are analysed to show the efficiency and convergence of the method.
Dynamic crack-opening displacement of a mode III edge crack in a semi-infinite piezoceramic strip under electric excitation
Authors: Li X-F , Lee Kang Yong
Published: September 2007

The transient response of a semi-infinite transversely isotropic piezoceramic strip containing an edge crack is analysed for the case where electric excitation is suddenly exerted at the material end surface. The crack is assumed to be impermeable to electric field. Ahypersingular integral equation for crack-opening displacement (COD) is derived via solving the associated mixed initial-boundary-value problem and solved numerically based on a collocation technique. By performing a numerical inversion of Laplace transform, dynamic CODs are determined and illustrated graphically.
Research on novel shape memory alloy multi-fingered humanoid hand
Authors: Yang K , Gu C L
Published: September 2007

Two new type actuators named planar bending embedded shape memory alloy actuator (ESMAA) and spacial bending ESMAA were presented. Using shape memory effect of SMA wires and elasticity of room temperature vulcanization silicone rubber, the ESMAAs could output force and bend displacement steadily. Furthermore, a novel three-fingered humanoid robot hand consisting of six ESMAAs was developed first. The structural parameters of the actuators, such as rod's radius, wire's radius, wire's recoverable curvature, and offset distance were optimized by combining analytical model with experimental results. On the basis of bionics, the lengths of hand's knuckles were determined through statistical research on the configuration of human beings' hands. The locations of fingers were carefully chosen through a volume optimal index. It is shown in the experiments that maximum angle between ends' tangents of each finger are 68.5°, 79°, and 79°, respectively. The tip of each finger could reach its final position approximately at the same time and by controlling the bending of each finger, the hand could accomplish fine manipulation like that of a human being.
A theoretical study on the response of a point elasto-hydrodynamic lubrication contact to a normal harmonic vibration under thermal and non-Newtonian conditions
Authors: Yang P , Cui J , Jin J M , Dowson D
Published: September 2007

Time-dependent thermal and non-Newtonian elastohydrodynamic lubrication of an elliptical point contact subjected to a normal harmonic vibration was studied numerically in this work. The contact was idealized as between an infinite plane and a spherical roller. The normal vibration of the roller was described by specifying the centre of the spherical roller to the infinite plane (without deformation) as a cyclic function of time. The shear-thinning rheological property of the lubricant was described by the Eyring model. The time-dependent numerical solution was achieved instant after instant in each period of a vibration. The periodic errors were checked at the end of each vibration cycle until the responses of variables such as pressure, film thickness, and temperature were all periodic functions with the same frequency of the roller's vibration. At each instant, the pressure field was solved with a multi-grid method, the surface deflection produced by pressure was determined with a multi-level multi-integration technique, the non-Newtonian flow of the lubricant was considered by using the equivalent viscosity calculated according to the shear-strain rate along the entrainment direction only, and the temperature field was evaluated with a finite-difference scheme through a column-by-column relaxation process. The computing time for a cyclic solution was 12–15 h on a personal computer with a 3.0 GHz central processing unit. The effects of both the amplitude and the frequency of the vibration were investigated. It was shown that the time-dependent solution is significantly different from the steady-state solution, especially when the amplitude of vibration is large and the frequency of vibration is high. Corresponding to a typical thermal and non-Newtonian case, numerical solutions were also obtained under isothermal and Newtonian, isothermal and non-Newtonian, and thermal and Newtonian conditions. Comparisons between these solutions indicate that, under time-dependent conditions, the effects of thermal and non-Newtonian flow are similar to those under steady-state conditions.
TRAP-5′ stem–loop interaction increases the efficiency of transcription termination in the Bacillus subtilis trpEDCFBA operon leader region
Authors: McGraw Adam P. , Bevilacqua Philip C. , Babitzke Paul
Published: September 2007

TRAP regulates expression of the Bacillus subtilis trpEDCFBA operon by a transcription attenuation mechanism in which tryptophan-activated TRAP binds to 11 (G/U)AG repeats in the nascent trp leader transcript. Bound TRAP blocks formation of an antiterminator structure and allows formation of an overlapping intrinsic terminator upstream of the trp operon structural genes. A 5′ stem–loop (5′SL) structure located upstream of the triplet repeat region also interacts with TRAP. TRAP-5′SL RNA interaction participates in the transcription attenuation mechanism by preferentially increasing the affinity of TRAP for the nascent trp leader transcript during the early stages of transcription, when only a few triplet repeats have been synthesized. Footprinting assays indicated that the 5′SL contacts TRAP through two discrete groups of single-stranded nucleotides that lie in the hairpin loop and in an internal loop. Filter binding and in vivo expression assays of 5′SL mutants established that G7, A8, and A9 from the internal loop, and A19 and G20 from the hairpin loop are critical for proper 5′SL function. These nucleotides are conserved among certain other 5′SL-containing organisms. Single-round transcription results indicated that the 5′SL increases the termination efficiency when transcription is fast; however, the influence of the 5′SL was lost when transcription was slowed by reducing the ribonucleoside triphosphate concentration. Since there is a limited amount of time for TRAP to bind to the nascent transcript and promote termination, our data suggest that the contribution of TRAP–5′SL interaction increases the rate of TRAP binding, which, in turn, increases the efficiency of transcription termination.
Saturation mutagenesis of a +1 programmed frameshift-inducing mRNA sequence derived from a yeast retrotransposon
Authors: Guarraia Carla , Norris Laura , Raman Ana , Farabaugh Philip J.
Published: September 2007

Errors during the process of translating mRNA information into protein products occur infrequently. Frameshift errors occur less frequently than other types of errors, suggesting that the translational machinery has more robust mechanisms for precluding that kind of error. Despite these mechanisms, mRNA sequences have evolved that increase the frequency up to 10,000-fold. These sequences, termed programmed frameshift sites, usually consist of a heptameric nucleotide sequence, at which the change in frames occurs along with additional sequences that stimulate the efficiency of frameshifting. One such stimulatory site derived from the Ty3 retrotransposon of the yeast Saccharomyces cerevisiae (the Ty3 stimulator) comprises a 14 nucleotide sequence with partial complementarity to a Helix 18 of the 18S rRNA, a component of the ribosome's accuracy center. A model for the function of the Ty3 stimulator predicts that it base pairs with Helix 18, reducing the efficiency with which the ribosome rejects erroneous out of frame decoding. We have tested this model by making a saturating set of single-base mutations of the Ty3 stimulator. The phenotypes of these mutations are inconsistent with the Helix 18 base-pairing model. We discuss the phenotypes of these mutations in light of structural data on the path of the mRNA on the ribosome, suggesting that the true target of the Ty3 stimulator may be rRNA and ribosomal protein elements of the ribosomal entry tunnel, as well as unknown constituents of the solvent face of the 40S subunit.
When impulses take over: Moderated predictive validity of explicit and implicit attitude measures in predicting food choice and consumption behaviour
Authors: Friese Malte , Hofmann Wilhelm , Wänke Michaela
Published: September 2007

Recent theories in social psychology suggest that explicitly measured attitudes are particularly valuable for the prediction of deliberate, controlled behaviour. In contrast, implicitly measured attitudes are assumed to be more important for the prediction of less controlled, more impulsive behaviour. Yet, conclusive evidence for the differential predictive validity of both measures is scarce. We hypothesized that limitations of different control resources would lead to functionally equivalent effects. In Study 1, cognitive capacity moderated the predictive validity of both explicit and implicit attitude measures in a choice task. Self‐regulatory resources led to similar patterns for eating (Study 2) and drinking behaviour (Study 3). In addition to the predictive validity of implicit and explicit attitude measures, in Study 3 we more closely investigated the relative contributions of explicitly measured attitudes and general restraint standards as two distinct, but complementing constructs that are dependent on control resources.
Progress toward Ultrafast DNA Sequencing Using Solid-State Nanopores
Authors: Soni Gautam V , Meller Amit
Published: September 2007

Background: Measurements of the ionic current flowing through nanometer-scale pores (nanopores) have been used to analyze single DNA and RNA molecules, with the ultimate goal of achieving ultrafast DNA sequencing. However, attempts at purely electronic measurements have not achieved the signal contrast required for single nucleotide differentiation. In this report we propose a novel method of optical detection of DNA sequence translocating through a nanopore.

Methods: Each base of the target DNA sequence is 1st mapped onto a 2-unit code, 2 10-bp nucleotide sequence, by biochemical conversion into Designed DNA Polymers. These 2-unit codes are then hybridized to complementary, fluorescently labeled, and self-quenching molecular beacons. As the molecular beacons are sequentially unzipped during translocation through a <2-nm-wide nanopore, their fluorescent tags are unquenched and are detected by a custom-built dual-color total internal reflection fluorescence (TIRF) microscope. The 2-color optical signal is then correlated to the target DNA sequence.

Results: A dual-color TIRFM microscope with single-molecule resolution was constructed, and controlled fabrication of 1-dimensional and 2-dimensional arrays of solid-state nanopores was performed. A nanofluidic cell assembly was constructed for TIRF-based optical detection of voltage-driven DNA translocation through a nanopore.

Conclusions: We present a novel nanopore-based DNA sequencing technique that uses an optical readout of DNA translocating unzipping through a nanopore. Our technique offers better single nucleotide differentiation in sequence readout, as well as the possibility of large-scale parallelism using nanopore arrays.
Effects of Drying Conditions, Phase Transformations, and Carbonation Reactions on Measurements of Sorption Isotherms of Building Materials
Authors: Wilkes Kenneth E. , Atchley Jerry A. , Childs Phillip W. , Desjarlais Andre
Published: September 2007

The sorption isotherm is one of the basic material properties used in hygrothermal modeling of building envelope performance. Measurement of this property is deceptively simple. Specimens are first dried and then exposed to a series of higher relative humidities to develop a curve of moisture content versus relative humidity at constant temperature. This paper discusses some confounding effects that we have observed while performing measurements on a number of common building materials. Materials studied included gypsum products, wood and wood products, and cementitious materials.
Perspectives: The Reintroduction of Natural Cement
Authors: Edison Leya L.
Published: September 2007

The development of natural cement technology was the culmination of thousands of years of research and development. Its rise to become the primary hydraulic binder used in buildings and structures in the United States occurred in the 19th century. Today, it is again finding a place in the restoration industry. Ultimately, it is the understanding of both the history of this technology and its redefinition in contemporary technical terms that will guide appropriate use of this traditional 19th century material in 21st century restoration work. The First and Second American Natural Cement Conferences brought together experts from a wide variety of disciplines in order to re-establish and augment the base of knowledge for this technology and our connection to it.
Techniques for Predicting Cladding Design Wind Pressures
Authors: Browne Matthew , Irwin Peter , Garber Jason , Cicci Michael , Dale Jan , Parnell Russ
Published: September 2007

With advances in wind tunnel methodologies in recent years, the measurement of wind loads on wind tunnel models of buildings and structures can be carried out with a high degree of accuracy. These results lead to more economical and risk-consistent structural designs than do code calculation methods. Five topics related to the prediction of cladding design wind pressures are examined in this paper: (1) wind tunnel testing and analysis methods, (2) integration of wind tunnel data with the full-scale wind climate, (3) evaluation of internal pressures, (4) duration of constant wind pressure for determining the load resistance of glass, and (5) computational fluid dynamics (CFD).
Design and Dynamic Practice of a Novel Fluid Vibration Isolator for Packaging Protection of Electronic Equipment
Authors: Ping Yang
Published: September 2007

The aim of this paper is to study a novel fluid-coupling vibration isolator to improve the dynamics in a harsh vibration-impact environment for packaging reinforcement systems of electronic equipment. The fluid-coupling isolator is designed through coupling the air, oil, rubber, and spring. The dynamic characteristics of the actual fluid-coupling isolator are developed. The test results of the prototype in dynamic tests show complex nonlinear dynamic characteristics. Based on this, a nonlinear dynamic model for the fluid-coupling isolator is presented. Comparisons with experimental data confirm the validity of the model. It builds a basis for future work in engineering design and evaluation of packaging protection system for electronic equipment.
Investigation of Friction in the Meso Normal Force Range on DLC and TiN Coatings
Authors: Achanta Satish , Drees Dirk , Celis Jean-Pierre , Anderson Michael
Published: September 2007

In recent years “low load” tribology has received more attention due to the emergence of special devices like MEMS, and new materials such as bioimplants, polymers, and textured surfaces. The tribological characterization of MEMS materials is challenging, because the devices operate at nominal contact pressures of only a few MPa and low wear rates of nm/h. The evaluation of materials with conventional high load tribological tools or with AFM type techniques is not appropriate because the contact pressures or contact geometries are not suitable. Furthermore, even in many conventional applications, the contact pressures and wear rates are more moderate than the ones achieved in conventional tribometers.

In this work, the friction and wear behavior of the commonly used industrial coatings titanium nitride (TiN) and diamond-like carbon (DLC) are investigated with normal forces in between Newton (conventional tribology) and nanoNewton (nanotribology). The investigation of friction at such low contact pressures was achieved using a high precision microtribometer MUST® operating in a linearly reciprocating ball-on-flat configuration; a ball-on-disk configuration is also possible. The equipment works on the principle of deflection measurements of a flexible cantilever beam with light optical sensors bearing a force resolution of 0.1 μN. As the applied normal force reduces from mNs to μNs, the effect of surface roughness becomes strikingly apparent in the recorded tangential force. The friction of TiN coating appears to be less sensitive to surface roughness variations and chemical changes of the countermaterial than DLC. The behavior of DLC at low contact pressures is different from the well known low friction behavior of DLC coatings at high contact pressures. The importance of the appropriate tribological tool for evaluating materials at low contact pressures has been illustrated through this study.
A general cross theorem with singularities
Authors: Jarnicki Marek , Pflug Peter
Published: September 2007

We present a general cross theorem for separately holomorphic and meromorphic functions with singularities.
Bounded pointwise approximation on open Riemann surfaces
Authors: Boivin André , Jiang Baoguo
Published: September 2007

A characterization of those open sets
Universal (pluri)subharmonic functions
Authors: Gauthier Paul M. , Pouryayevali Mohamad R.
Published: September 2007

In this note, we establish the existence of universal subharmonic functions on ℝ
Uniform approximation on the real axes by functions harmonic in a stripe and having optimal growth
Authors: Arakelian Norair , Vardanyan Anush
Published: September 2007

Let
Reasoning and proof in the mathematics classroom
Authors: Heinze Aiso , Reiss Kristina
Published: September 2007

Proving is an essential mathematical activity that should play an important role in the mathematics classroom. However, performing a proof is a most challenging task for students. The nature of this challenge is discussed from a theoretical perspective. Starting with thoughts on the role of proof in mathematics, the article continues with reflections on limiting factors for performing proofs and the learning of proof in the mathematics classroom. Since empirical research gives evidence that guided exploration and a cherishing atmosphere can be regarded as beneficial for learning processes, this topic will be addressed in a further section.
Reduced endogenous estrogen delays epididymal development but has no effect on efferent duct morphology in boars
Authors: Pearl Christopher A , At-Taras Eeman , Berger Trish , Roser Janet F
Published: September 2007

The study presented herein was designed to test the hypothesis that reduced endogenous estrogen in the boar alters efferent duct morphology, epididymal morphology, and steroid receptor expression. Twenty-eight littermate pairs of boars were treated with Letrozole, an aromatase inhibitor, or with vehicle from 1 week of age until castration at 2 through 8 months. Efferent ducts and epididymides were examined for morphological development and steroid receptor expression. Efferent duct morphology was not different between control and Letrozole-treated animals at any examined age. Androgen receptor (AR), estrogen receptor α (ERα), and β (ERβ) were expressed in the epithelial cells of the efferent ducts at all ages; expression was similar in control and treated animals. Morphological development of the caput and corpus was delayed in Letrozole-treated animals, but this delay was transient since morphology was similar between control and treated animals at 8 months. The cauda did not show a delay in development, but was more developed in treated animals at 2 months. AR, ERα, and ERβ were expressed in all three epididymal regions; no difference was observed between control and treated animals. In summary, estrogen appears to be important for development of the epididymis; however, the cauda may be regulated differently than the caput and corpus. Results for the efferent ducts suggest that the normally high endogenous estrogens are not required for regulation of fluid reabsorption in the boar. It also suggests that any ER activation required for maintenance of efferent duct morphology and function is normal in Letrozole-treated boars.
Autophagy Genes unc-51 and bec-1 Are Required for Normal Cell Size in Caenorhabditis elegans
Authors: Aladzsity István , Tóth Márton L , Sigmond Tímea , Szabó Emese , Bicsák Bertalan , Barna János , Regős Ágnes , Orosz László , Kovács Attila L , Vellai Tibor
Published: September 2007

Here we show that in the nematode Caenorhabditis elegans mutational inactivation of two autophagy genes unc-51/atg1 and bec-1/atg6/beclin1 results in small body size without affecting cell number. Furthermore, loss-of-function mutations in unc-51 and bec-1 suppress the giant phenotype of mutant animals with aberrant insulin-like growth factor-1 (insulin/IGF-1) or transforming growth factor-β (TGF-β) signaling. This function for unc-51 and bec-1 in cell size control and their interaction with these two growth modulatory pathways may represent a link between the hormonal and nutritional regulation of cell growth.
New Properties of Drosophila Fab-7 Insulator
Authors: Rodin Sergey , Kyrchanova Olga , Pomerantseva Ekaterina , Parshikov Alexander , Georgiev Pavel
Published: September 2007

In the Abd-B 3′ cis-regulatory region, which is subdivided into a series of iab domains, boundary elements have previously been detected, including the Fab-7 element providing for the autonomous functioning of the iab-6 and iab-7 cis-regulatory domains. Here, it has been shown that a single copy of the 860-bp Fab-7 insulator effectively blocks the yellow and white enhancers. The eye and testis enhancers can stimulate the white promoter across the pair of Fab-7, which is indicative of a functional interaction between the insulators. Unexpectedly, Fab-7 has proved to lose the enhancer-blocking activity when placed near the white promoter. It seems likely that Fab-7 strengthens the relatively weak white promoter, which leads to the efficient enhancer–promoter interaction and insulator bypass.
Genetic Background Modifies Inner Ear and Eye Phenotypes of Jag1 Heterozygous Mice
Authors: Kiernan Amy E , Li Renhua , Hawes Norman L , Churchill Gary A , Gridley Thomas
Published: September 2007

Mice heterozygous for missense mutations of the Notch ligand Jagged1 (Jag1) exhibit head-shaking behavior indicative of an inner ear vestibular defect. In contrast, mice heterozygous for a targeted deletion of the Jag1 gene (Jag1del1) do not demonstrate obvious head-shaking behavior. To determine whether the differences in inner ear phenotypes were due to the types of Jag1 mutations or to differences in genetic background, we crossed Jag1del1 heterozygous mice onto the same genetic background as the missense mutants. This analysis revealed that variation of the Jag1 mutant inner ear phenotype is caused by genetic background differences and is not due to the type of Jag1 mutation. Genome scans of N2 backcross mice identified a significant modifier locus on chromosome 7, as well as a suggestive locus on chromosome 14. We also analyzed modifiers of an eye defect in Jag1del1 heterozygous mice from this same cross.
Disruption of Topoisomerase II Perturbs Pairing in Drosophila Cell Culture
Authors: Williams Benjamin R , Bateman Jack R , Novikov Natasha D , Wu C-Ting
Published: September 2007

Homolog pairing refers to the alignment and physical apposition of homologous chromosomal segments. Although commonly observed during meiosis, homolog pairing also occurs in nonmeiotic cells of several organisms, including humans and Drosophila. The mechanism underlying nonmeiotic pairing, however, remains largely unknown. Here, we explore the use of established Drosophila cell lines for the analysis of pairing in somatic cells. Using fluorescent in situ hybridization (FISH), we assayed pairing at nine regions scattered throughout the genome of Kc167 cells, observing high levels of homolog pairing at all six euchromatic regions assayed and variably lower levels in regions in or near centromeric heterochromatin. We have also observed extensive pairing in six additional cell lines representing different tissues of origin, different ploidies, and two different species, demonstrating homolog pairing in cell culture to be impervious to cell type or culture history. Furthermore, by sorting Kc167 cells into G1, S, and G2 subpopulations, we show that even progression through these stages of the cell cycle does not significantly change pairing levels. Finally, our data indicate that disrupting Drosophila topoisomerase II (Top2) gene function with RNAi and chemical inhibitors perturbs homolog pairing, suggesting Top2 to be a gene important for pairing.
Tradition as a Resource
Authors: Hill Michael
Published: September 2007

This introductory article reflects on a personal interest in the concept of tradition. Two contrasting sociological approaches to tradition are examined, the first being the structural-functionalist treatment of tradition as embedded and institutionalized, the second the more dynamic Weberian approach to tradition which links it with charismatic breakthroughs. Using the latter, it is possible to speak of a ‘revolution by tradition’ and to indicate different referents of tradition in the Church of England. A recent study of Hawksmoor’s London churches shows the attempted embodiment of primitive tradition in their architecture. In a very different context, Maori prophetic movements in nineteenth-century New Zealand reveal the potential for tradition to provide a charismatic springboard. A third example of the innovative potential of tradition is located in the ‘Asian values’ debate, where a constructed cluster of values surrounding neo-Confucianism can be associated with what is termed ‘reverse Orientalism’. Ideological discourse in Singapore provides an important test of the ‘Asia Values’ model. Finally, features of each article in this special issue are highlighted.
Creation and Innovation in Australian Paganism
Authors: Hume Lynne
Published: September 2007

This article gives a brief account of the background to contemporary Paganism, its emergence in Australia, discusses some of its key players and publications, and then discusses the increasing focus on Paganism as a nature religion. It demonstrates how practitioners have had to employ innovation and a re-working of the myth cycle because of the particular environments within which they ?nd themselves. The southern hemisphere raises some unique problems which have to be reconciled, and Aboriginal Australian spirituality, with its deep connections with the land, has had an effect on this innovation as well.
A Tale of Two Celticities
Authors: Bowman Marion
Published: September 2007

This article examines examples of Celtic revival in the context of contemporary spirituality in the city of Bath, in the south west of England.
Two case studies are featured, one involving the hot springs of Bath and the other Bath’s alleged ‘Druidic’ heritage. In both cases, there have been revivals which look to a Celtic past as a model for the present, and a vision for the future. However, a variety of markers and measures of Celticity emerge in the study, indicating that that there is an ongoing negotiation over the meaning and conception of what it means to be Celtic.
It is clear that contemporary Celtic spirituality provides a flexible vehicle through which the past can be explored, reassessed and to some extent re-established, and the present can be imbued with significance and sacrality. As examples of vernacular religion, the case studies also indicate that Bath itself is considered a major force in determining the nature of religiosity to emerge there.
Purification and Localization of Nitric Oxide Synthases from Hybrid Tilapia (Nile Tilapia × Mozambique Tilapia)
Authors: Wang Way-Shyan , Hung Shao-Wen , Lin Yu-Hsing , Tu Ching-Yu , Wong Min-Liang , Chiou Shiow-Her , Shieh Meng-Tong
Published: September 2007

The aims of this study were to purify and localize the nitric oxide synthases (NOSs) from hybrid tilapia (Nile tilapia Oreochromis niloticus × Mozambique tilapia O. mossambicus). The purification procedures involved affinity chromatography with a 2′, 5′-ADP-agarose 4B column and ion exchange with a diethylaminoethanol Bio-Gel A column. The results from gel filtration assays showed that the molecular weights of neuronal NOS (nNOS) and inducible NOS (iNOS) were 178 and 120 kDa, respectively. The sodium dodecyl sulfate–polyacrylamide gel electrophoresis results showed that there were three bands with molecular weights of 89, 47, and 29 kDa from the purified nNOS. However, only one band, with a molecular weight of 120 kDa, appeared on the gel from the purified iNOS. Hybrid tilapia nNOS was a dimer structure, while iNOS appeared to be a monomer structure. Moreover, our results revealed that the activities of nNOS and iNOS were significantly higher after the addition of Ca+2 or Mg+2 ions individually. However, when l-arginine and NADPH were present, the addition of 1 mM of either ion did not further increase the activity. The chemical l-NG-methyl-l-arginine could inhibit the activities of the purified NOSs with or without l-arginine. Western blot analyses showed only an 89-kDa immunoreactive band from the extracts of cerebrum; however, we did not find the specific bands in other tissues, such as gill, intestine, liver, spleen, and anterior kidney. We found another 120-kDa immunoreactive protein band with the rabbit antirat iNOS serum against iNOS from the extracts of anterior kidney and spleen. The results of immunohistochemistry with the rabbit antihuman nNOS serum indicated that the nNOS existed in the cerebellum, olfactory bulb, diencephalons, and nerve cell bodies and neuronal fibers of the spinal cord. Interestingly, only macrophages from anterior kidney and spleen showed positive reactions with the rabbit antirat iNOS serum. In the same way, the endothelial NOS (eNOS) located in the heart and epithelial cells of the blood vessels reacted positively with the rabbit antibovine eNOS serum.
Use of Eyeballs for Establishing Ploidy of Asian Carp
Authors: Jenkins Jill A. , Thomas R. Glenn
Published: September 2007

Grass carp Ctenopharyngodon idella, silver carp Hypophthalmichthys molitrix, and bighead carp H. nobilis are now established and relatively common in the Mississippi and Atchafalaya rivers. Commercial fishers of Louisiana's large rivers report recurrent catches of grass carp, and the frequency of bighead carp and silver carp catch is increasing. Twelve black carp Mylopharyngodon piceus were recently captured from the Mississippi and Atchafalaya River system, and 10 were analyzed for ploidy. By using the methods described herein, all 10 fish were determined to be diploid. Such correct identifications of ploidy of feral Asian carp species, as well as other species, would provide science-based information constructive for meeting reporting requirements, tracking fish movements, and forecasting expansion of species distribution. To investigate the postmortem period for sample collection and to lessen demands on field operations for obtaining samples, a laboratory study was performed to determine the length of time for which eyeballs from postmortem black carp could be used for ploidy determinations. Acquiring eyes rather than blood is simpler and quicker and requires no special supplies. An internal DNA reference standard with a documented genome size, including erythrocytes from diploid black carp or Nile tilapia Oreochromis niloticus, was analyzed simultaneously with cells from seven known triploid black carp to assess ploidy through 12 d after extraction. Ploidy determinations were reliable through 8 d postmortem. The field process entails excision of an eyeball, storage in a physiological buffer, and shipment within 8 d at refrigeration temperatures (4°C) to the laboratory for analysis by flow cytometry.
Differentiation and Enrichment of Hepatocyte-Like Cells from Human Embryonic Stem Cells In Vitro and In Vivo
Authors: Duan Yuyou , Catana Andreea , Meng Ying , Yamamoto Naoki , He Songqing , Gupta Sanjeev , Gambhir Sanjiv Sam , Zern Mark A.
Published: September 2007

Human embryonic stem cells (hESC) may provide a cell source for functional hepatocytes. The aim of this study is to establish a viable human hepatocyte-like cell line from hESC that can be used for cell-based therapies. The differentiated hESC were enriched by transducing with a lentivirus vector containing the green fluorescent protein (GFP) gene driven by the α1-antitrypsin promoter; the GFP gene is expressed in committed hepatocyte progenitors and hepatocytes. GFP+ hESC were purified by laser microdissection and pressure catapulting. In addition, differentiated hESC that were transduced with a lentivirus triple-fusion vector were transplanted into NOD-SCID mice, and the luciferase-induced bioluminescence in the livers was evaluated by a charge-coupled device camera. GFP+ hESC expressed a large series of liver-specific genes, and expression levels of these genes were significantly improved by purifying GFP+ hESC; our results demonstrated that purified differentiated hESC express nearly physiological levels of liver-specific genes and have liver-specific functions that are comparable to those of primary human hepatocytes. The differentiated hESC survived and engrafted in mouse livers, and human liver-specific mRNA and protein species were detected in the transplanted mouse liver and serum at 3 weeks after transplantation. This is the first time that human albumin generated by hESC-derived hepatocytes was detected in the serum of an animal model. This also represents the first successful transplantation of differentiated hESC in an animal liver and the first bioluminescence imaging of hESC in the liver. This study is an initial step in establishing a viable hepatocyte-like cell line from hESC.

Disclosure of potential conflicts of interest is found at the end of this article.
Simulating Source‐Limited and Sink‐Limited Kernel Set with CERES‐Maize
Authors: Lizaso J. I. , Fonseca A. E. , Westgate M. E.
Published: September 2007

CERES‐Maize simulates kernel set as a source‐limited process based on average plant growth rate during the lag phase after flowering. Yet the number of kernels formed by maize (Zea mays L.) also depends on timely interaction between male and female flowers, which can limit formation of reproductive sinks under some conditions. Failure to account for sink‐limited kernel set may contribute to simulation error observed under conditions that affect dynamics of pollen shed or silking, but do not alter crop growth rate. We developed algorithms for a Flowering Model to simulate sink‐limited kernel set from flowering dynamics. This model was calibrated against kernel production in hybrid seed production fields and then linked to CERES‐Maize. The Modified CERES‐Maize was calibrated against two years of field data involving three hybrids, eight population densities, and seven N levels. Integrating the capacity to simulate sink‐limited kernel set with source‐limited kernel set increased simulation accuracy dramatically, relative to original CERES‐Maize. For 13 commercial fields tested, Modified CERES‐Maize decreased simulation error for kernels per plant from 17.1 to 2.3%, improved r2 between measured and simulated values from 0.77 to 0.87, and decreased simulation error indicators mean error, root mean square error, and mean square deviation by 85, 40, and 64%, respectively. Modified CERES‐Maize accounts for a much greater range of variability in the biological processes controlling kernel set.
The Long‐Term Impact of Phosphorus and Potassium Fertilization on Alfalfa Yield and Yield Components
Authors: Berg W. K. , Cunningham S. M. , Brouder S. M. , Joern B. C. , Johnson K. D. , Santini J. B. , Volenec J. J.
Published: September 2007

Addition of P and K fertilizer can increase alfalfa (Medicago sativa L.) yield and stand persistence, but the yield components associated with P‐ and K‐induced variation in agronomic performance are not clear. Our objectives were: (i) to determine the impact of P and K nutrition on productivity of a relatively old alfalfa stand; and (ii) determine which yield components are associated with changes in alfalfa forage yield. Treatments were a factorial combination of four P and five K rates replicated four times. Forage harvests occurred four times annually. Plant populations were determined in early December and late May each year. When compared to unfertilized plots, addition of P and K increased forage yield each year. Fertilization with P decreased plants m−2 at all K application rates, but especially in plots fertilized with P, but not K. By comparison, plots fertilized with K, but not fertilized with P, had the higher plant population densities. Although regression analysis eventually revealed a positive association between forage yield and shoots m−2 in 2003 and 2004, the greatest forage yields were not obtained in plots with the greatest plant population densities, shoots plant−1 or shoots m−2 Regression and path analysis revealed that improved forage yield in P‐ and K‐fertilized plots was consistently associated with greater mass shoot−1
Mowing Strategies and Dew Removal to Minimize Dollar Spot on Creeping Bentgrass
Authors: Ellram Alex , Horgan Brian , Hulke Brent
Published: September 2007

Dollar spot (DS) disease (caused by Sclerotinia homoeocarpa F.T. Bennett) on bentgrass (Agrostis spp.) can be greatly reduced by implementing mowing and other cultural practices that reduce leaf wetness duration (LWD). Field studies were conducted in 2004 and 2005 to discern the effects of dew removal time (mowing at 0400, 1000, or 2200 h), method of dew removal (mowing with sharp or dull mower or squeegee), and frequency of dew removal (daily or alternate days) on the incidence of DS on fairway height (16 mm) creeping bentgrass (Agrostis stolonifera L.). The severity of DS was studied in laboratory experiments with 6, 12, and 18 h LWD. Dollar spot incidence on field test plots was lowest when mowing treatments were conducted at 0400 h. In addition plots mowed at 2200 h had significantly lower DS incidence than plots mowed at 1000 h. Mowing with either a sharp or dull reel mower proved more effective in reducing DS than alternating mowing with a squeegee for dew removal. Dull mower blades were as effective as sharp mower blades in reducing DS in our field studies. Dollar spot incidence was also lower when dew was removed daily than when dew was removed on alternate days. Mowing at 0400 h daily was the most effective treatment for reducing DS on creeping bentgrass plots in both 2004 and 2005. In laboratory experiments, DS lesion size increased as LWD increased. Specifically, disruption of leaf moisture after 6 h of uninterrupted LWD appeared to be most effective in reducing DS lesion diameter.
Occurrence of the Waxy Alleles wxa and wxb in Waxy Sorghum Plant Introductions and Their Effect on Starch Thermal Properties
Authors: Pedersen J. F. , Graybosch R. A. , Funnell D. L.
Published: September 2007

The existence of two waxy alleles, wxa associated with no detectable granule bound starch synthase (GBSS) and wxb associated with apparently inactive GBSS, was recently reported in sorghum [Sorghum bicolor (L.) Moench]. In this paper, the occurrence of the wxa and wxb alleles in the USDA‐ARS photoperiod‐insensitive sorghum collection was determined, and the effects of the wxa and wxb alleles on thermal properties of sorghum starch (gelatinization temperatures and energy requirements) measured by differential scanning calorimetry. Of the 51 purported waxy accessions examined, 14 tested positive for presence of amylose by iodine staining and were considered to be previously misclassified wild‐type lines. Nine accessions were mixed for presence or absence of amylose. Twenty‐four of the 28 accessions confirmed to be waxy by negative iodine staining for amylose had no detectable GBSS using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) (wxa), and four were show to contain GBSS (wxb). Mean gelatinization onset, peak, and end temperatures were significantly lower for wild‐type than either of the two waxy genotypes. Mean gelatinization onset temperature was slightly higher for waxy‐GBSS+ genotypes than waxy‐GBSS− genotypes. Mean gelatinization end temperature was slightly higher for waxy‐GBSS− genotypes than waxy‐GBSS+ genotypes. Significant genetic variation was observed within genotypic classes, suggesting influence of additional modifier genes affecting sorghum starch structure or micro‐environmental effects.
Effects of High Temperature and Drought on a Hybrid Bluegrass Compared with Kentucky Bluegrass and Tall Fescue
Authors: Su Kemin , Bremer Dale J. , Keeley Steven J. , Fry Jack D.
Published: September 2007

High temperature and drought stresses may reduce quality in cool‐season turfgrasses during summer months in the transition zone. This growth chamber study was conducted to evaluate effects of high temperature and drought on physiology and growth of ‘Apollo’ Kentucky bluegrass (Poa pratensis L.) (KBG), ‘Dynasty’ tall fescue (Festuca arundincea Schreb.) (TF), and ‘Thermal Blue’, a hybrid (HBG) between KBG and Texas bluegrass (Poa arachnifera Torr.). Turfgrasses were exposed for 48 d to supra‐optimal (high temperature; 35/25°C, 14‐h day/10‐h night) and optimal (control; 22/15°C, 14‐h day/10‐h night) temperatures under well‐watered (100% evapotranspiration [ET] replacement) and deficit (60% ET replacement) irrigation. Heat resistance was greater in HBG, which had greater visual quality, gross photosynthesis (Pĝ), dry matter production, and lower electrolyte leakage and soil surface temperatures than KBG and TF under high temperature. Cumulative Pĝ during the study was 16 and 24% greater in HBG than in KBG and TF, respectively. Green leaf area index (LAI) in HBG was not affected by high temperature, but LAI was reduced by 29% in KBG and 38% in TF. Differences in drought resistance were negligible among species. The combination of high temperature and drought caused rapid declines in visual quality and dry matter production, but HBG generally performed better. Results indicated greater heat resistance, but not drought resistance, in HBG than in KBG or TF.
A Cryptic Wheat–Aegilops triuncialis Translocation with Leaf Rust Resistance Gene Lr58
Authors: Kuraparthy Vasu , Sood Shilpa , Chhuneja Parveen , Dhaliwal Harcharan S. , Kaur Satinder , Bowden Robert L. , Gill Bikram S.
Published: September 2007

Genes transferred to crop plants from wild species are often associated with deleterious traits. Using molecular markers, we detected a cryptic introgression with a leaf rust resistance gene transferred from Aegilops triuncialis L. into common wheat (Triticum aestivum L.). One agronomically desirable rust‐resistant introgression line was selected and advanced to BC3F11 from a cross of hexaploid wheat and A. triuncialis In situ hybridization using A. triuncialis genomic DNA as a probe failed to detect the alien introgression. The translocation line was resistant to the most prevalent races of leaf rust in India and Kansas. Genetic mapping in a segregating F2:3 population showed that the rust resistance was monogenically inherited. Homeologous group 2 restriction fragment length polymorphism markers XksuF11, XksuH16, and Xbg123 showed diagnostically polymorphic alleles between the resistant and susceptible bulks. The alien transfer originated from homeologous chromosome recombination. The A. triuncialis‐specific alleles of XksuH16, XksuF11, Xbg123, and one simple sequence repeat marker Xcfd50 cosegregated with the rust resistance, suggesting that the wheat–A. triuncialis translocation occurred in the distal region of chromosome arm 2BL. This translocation was designated T2BS·2BL‐2tL(0.95). The unique source and map location of the introgression on chromosome 2B indicated that the leaf rust resistance gene is new and was designated Lr58
Genetic Variability and Relationships for Adaptive, Morphological, and Biomass Traits in Chinese Bermudagrass Accessions
Authors: Wu Y. Q. , Taliaferro C. M. , Martin D. L. , Anderson J. A. , Anderson M. P.
Published: September 2007

Bermudagrass, Cynodon dactylon (L.) Pers., is geographically widely distributed and represents the most important taxon in the genus in terms of its extensive uses for turf, forage, soil stabilization, and remediation. This warm‐season, sod‐forming grass is indigenous to China, but limited information is available for adaptive, morphological, and biomass traits in the Chinese germplasm. Accordingly, objectives of this study were to quantify genetic variability for 24 morphological, adaptive, and biomass‐related traits and to characterize relationships among traits of 114 Chinese clonal accessions in a field experiment at Stillwater, OK. ‘Tifsport’, ‘Tifway’, ‘Midland’, and ‘Tifton 44’ bermudagrass cultivars were used as controls in the field experiment. Differences among the accessions were significant (P < 0.01 or P < 0.05) and of large magnitude for all response traits. When grouped by ploidy level, variation among accessions was far greater in tetraploids (104) than in pentaploids (3) and hexaploids (7). Response traits of plant height, leaf blade length and width, and internode length and diameter were significantly and positively correlated with each other to various degrees. Biomass yield was significantly associated with the traits of spring greenup, plant height, winter kill rate, internode, and sod density. Winter kill was positively correlated with weed prolificacy, but negatively with spring greenup. Multiple regression and path coefficient analyses indicated plant height, winter kill, greenup, sod density, and internode size to be predictive of forage yield. The large amount of genetic variability among the Chinese accessions should be a valuable resource for the development of improved turf and forage cultivars.