bluuebunny/crossref_metadata_2025 huggingface dataset:
Vapor-liquid nucleation of argon: Exploration of various intermolecular potentials
Authors: McGrath Matthew J. , Ghogomu Julius N. , Tsona Narcisse T. , Siepmann J. Ilja , Chen Bin , Napari Ismo , Vehkamäki Hanna
Published: August 2010

The homogeneous vapor-liquid nucleation of argon has been explored at T=70 and 90 K using classical nucleation theory, semiempirical density functional theory, and Monte Carlo simulations using the aggregation-volume-bias algorithm with umbrella sampling and histogram-reweighting. In contrast with previous simulation studies, which employed only the Lennard-Jones intermolecular potential, the current studies were carried out using various pair potentials including the Lennard-Jones potential, a modified Buckingham exponential-six potential, the Barker–Fisher–Watts pair potential, and a recent ab initio potential developed using the method of effective diameters. It was found that the differences in the free energy of formation of the critical nuclei between the potentials cannot be explained solely in terms of the difference in macroscopic properties of the potentials, which gives a possible reason for the failure of classical nucleation theory.
Bolometric terahertz detection in pinched-off quantum point contacts
Authors: Song J. W. , Aizin G. R. , Mikalopas J. , Kawano Y. , Ishibashi K. , Aoki N. , Reno J. L. , Ochiai Y. , Bird J. P.
Published: August 2010

Terahertz (>1 THz) irradiation of pinched-off quantum point contacts (QPCs) generates a pronounced photo-current due to radiation-induced heating. This response is reproduced by a model of temperature-dependent transmission through a saddle potential, confirming its bolometric nature.
Quantum chemistry and molecular dynamics studies of the entropic elasticity of localized molecular kinks in polyisoprene chains
Authors: Hanson David E. , Martin Richard L.
Published: August 2010

We investigate the thermodynamic consequences of the distribution of rotational conformations of polyisoprene on the elastic response of a network chain. In contrast to the classical theory of rubber elasticity, which associates the elastic force with the distribution of end-to-end distances, we find that the distribution of chain contour lengths provides a simple mechanism for an elastic force. Entropic force constants were determined for small contour length extensions of chains constructed as a series of localized kinks, with each kink containing between one and five cis-1,4-isoprene units. The probability distributions for the kink end-to-end distances were computed by two methods: (1) by constructing a Boltzmann distribution from the lengths corresponding to the minimum energy dihedral rotational conformations, obtained by optimizing isoprene using first principles density functional theory, and (2) by sampling the trajectories of molecular dynamics simulations of an isolated molecule composed of five isoprene units. Analogous to the well-known tube model of elasticity, we make the assumption that, for small strains, the chain is constrained by its surrounding tube, and can only move, by a process of reptation, along the primitive path of the contour. Assuming that the chain entropy is Boltzmann’s constant times the logarithm of the contour length distribution, we compute the tensile force constants for chain contour length extension as the change in entropy times the temperature. For a chain length typical of moderately crosslinked rubber networks (78 isoprene units), the force constants range between 0.004 and 0.033 N/m, depending on the kink size. For a cross-linked network, these force constants predict an initial tensile modulus of between 3 and 8 MPa, which is comparable to the experimental value of 1 MPa. This mechanism is also consistent with other thermodynamic phenomenology.
Transitional and turbulent boundary layer with heat transfer
Authors: Wu Xiaohua , Moin Parviz
Published: August 2010

We report on our direct numerical simulation of an incompressible, nominally zero-pressure-gradient flat-plate boundary layer from momentum thickness Reynolds number 80–1950. Heat transfer between the constant-temperature solid surface and the free-stream is also simulated with molecular Prandtl number Pr=1. Skin-friction coefficient and other boundary layer parameters follow the Blasius solutions prior to the onset of turbulent spots. Throughout the entire flat-plate, the ratio of Stanton number and skin-friction St/Cf deviates from the exact Reynolds analogy value of 0.5 by less than 1.5%. Mean velocity and Reynolds stresses agree with experimental data over an extended turbulent region downstream of transition. Normalized rms wall-pressure fluctuation increases gradually with the streamwise growth of the turbulent boundary layer. Wall shear stress fluctuation, τw,rms′+, on the other hand, remains constant at approximately 0.44 over the range, 800<Reθ<1900. Turbulent Prandtl number Prt peaks at around 1.9 at the wall, and decreases monotonically toward the boundary layer edge with no near-wall secondary peak, in good agreement with previous boundary layer heat transfer experiments. In the transitional region, turbulent spots are tightly packed with numerous hairpin vortices. With the advection and merging of turbulent spots, these young isolated hairpin forests develop into the downstream turbulent region. Isosurfaces of temperature up to Reθ=1900 are found to display well-resolved signatures of hairpin vortices, which indicates the persistence of the hairpin forests.
Ring-shaped electric discharge as an igniter of gas mixtures
Authors: Barkhudarov E M , Berezhetskaya N K , Kop'ev V A , Kossyi I A , Popov N A , Taktakishvili M I , Temchin S M
Published: August 2010

Results are presented from experimental studies of ignition of a stoichiometric methane–oxygen mixture in a closed chamber by a ring electric discharge. It is shown that the process of fast (explosive) ignition of the reactor volume starts on the axis of the ring, near its centre, i.e. at a distance from the annular region of power deposition. Experimental evidence suggests that the ignition of a combustible gas mixture near the axis is triggered by strong gas-dynamic perturbations converging to the axis, radially propagating from the ring discharger.
Modelling effective dielectric properties of materials containing diverse types of biological cells
Authors: Huclova Sonja , Erni Daniel , Fröhlich Jürg
Published: August 2010

An efficient and versatile numerical method for the generation of different realistically shaped biological cells is developed. This framework is used to calculate the dielectric spectra of materials containing specific types of biological cells. For the generation of the numerical models of the cells a flexible parametrization method based on the so-called superformula is applied including the option of obtaining non-axisymmetric shapes such as box-shaped cells and even shapes corresponding to echinocytes. The dielectric spectra of effective media containing various cell morphologies are calculated focusing on the dependence of the spectral features on the cell shape. The numerical method is validated by comparing a model of spherical inclusions at a low volume fraction with the analytical solution obtained by the Maxwell–Garnett mixing formula, resulting in good agreement. Our simulation data for different cell shapes suggest that around 1MHz the effective dielectric properties of different cell shapes at different volume fractions significantly deviate from the spherical case. The most pronounced change exhibits εeff between 0.1 and 1 MHz with a deviation of up to 35% for a box-shaped cell and 15% for an echinocyte compared with the sphere at a volume fraction of 0.4. This hampers the unique interpretation of changes in cellular features measured by dielectric spectroscopy when simplified material models are used.
Mutations in the P3 Protein of Soybean mosaic virus G2 Isolates Determine Virulence on Rsv4-Genotype Soybean
Authors: Chowda-Reddy R. V. , Sun Haiyue , Chen Hongyan , Poysa Vaino , Ling Hong , Gijzen Mark , Wang Aiming
Published: August 2010

Two Soybean mosaic virus (SMV) G2 isolates, L and L-RB, sharing high-sequence similarly but differing in ability to break Rsv4-mediated resistance in soybean, were investigated. Infectious clones corresponding to these two isolates and their chimeric clones resulting from swapping different regions of genomic cDNA between L and L-RB were constructed. Only L-RB or chimeras containing the middle fragment of L-RB cDNA showed virulence on Rsv4–genotype soybean. Sequence comparison analysis revealed that the middle genomic region of L and L-RB encodes four different amino acids. Point mutagenesis demonstrated that a single amino acid substitution (Q1033K) in the P3 protein determined virulence toward Rsv4 resistance. In addition, six new SMV Rsv4 resistance-breaking isolates, variants of the second passage on Williams 82 infected with the chimeras or mutants noninfectious on soybean carrying Rsv4, were obtained. Sequencing data indicated that these new isolates contain either the Q1033K mutation or a new substitution (G1054R) in P3. Site-directed mutagenesis confirmed the virulence role of the G1054R mutation on Rsv4-genotype soybean. Taken together, these data suggest that P3 of the SMV G2 strain is an avirulent determinant for Rsv4 and one single nucleotide mutation in P3 may be sufficient to compromise its elicitor function.
Identification of Regional Climatic Conditions Favorable for Development of European Canker of Apple
Authors: Beresford Robert M. , Kim Kwang Soo
Published: August 2010

Months of the year with high risk of European canker (Neonectria galligena) development in areas of the United States, Chile, England, and Northern Ireland were determined from published data. Moving-window analysis of long-term climatic data was used to classify disease risk in these areas in relation to rainfall and temperature conditions using the degree of agreement statistic. Greatest agreement occurred when it both rained on >30% of days/month and there was an average of >8 h/day with temperature of 11 to 16°C. When these thresholds were applied in eight validation areas in New Zealand, Australia, the United States, The Netherlands, and Denmark, areas with reported higher risk of disease tended to be areas where the thresholds were exceeded more often and by greater amounts. Areas at higher latitudes (>52°) with frequent summer rainfall appeared to be most prone to European canker, including the fruit rot phase of the disease, probably because summer temperatures were more favorable than at lower latitudes. The climatic thresholds derived for European canker could be useful for studies of disease establishment risk, surveillance, eradication, climate change impact assessment, and, possibly, for disease risk forecasting. The methods used in this study allowed conditions favorable for disease development to be identified even though quantitative regional disease data were lacking, and they could be useful for similar geoclimatic studies of other diseases.
Sequences, stratigraphy and scenarios: what can we say about the fossil record of the earliest tetrapods?
Authors: Friedman Matt , Brazeau Martin D.
Published: August 2010

Past research on the emergence of digit-bearing tetrapods has led to the widely accepted premise that this important evolutionary event occurred during the Late Devonian. The discovery of convincing digit-bearing tetrapod trackways of early Middle Devonian age in Poland has upset this orthodoxy, indicating that current scenarios which link the timing of the origin of digited tetrapods to specific events in Earth history are likely to be in error. Inspired by this find, we examine the fossil record of early digit-bearing tetrapods and their closest fish-like relatives from a statistical standpoint. We find that the Polish trackways force a substantial reconsideration of the nature of the early tetrapod record when only body fossils are considered. However, the effect is less drastic (and often not statistically significant) when other reliably dated trackways that were previously considered anachronistic are taken into account. Using two approaches, we find that 95 per cent credible and confidence intervals for the origin of digit-bearing tetrapods extend into the Early Devonian and beyond, spanning late Emsian to mid Ludlow. For biologically realistic diversity models, estimated genus-level preservation rates for Devonian digited tetrapods and their relatives range from 0.025 to 0.073 per lineage-million years, an order of magnitude lower than species-level rates for groups typically considered to have dense records. Available fossils of early digited tetrapods and their immediate relatives are adequate for documenting large-scale patterns of character acquisition associated with the origin of terrestriality, but low preservation rates coupled with clear geographical and stratigraphic sampling biases caution against building scenarios for the origin of digits and terrestrialization tied to the provenance of particular specimens or faunas.
Tumor antigen delivered by Salmonella III secretion protein fused with heat shock protein 70 induces protection and eradication against murine melanoma
Authors: Zhu Xiangying , Zhou Ping , Cai Jianguo , Yang Guimei , Liang Shenghua , Ren Daming
Published: August 2010

Attenuated Salmonella typhimurium possess the ability to stimulate innate immune responses and preferentially allocate within the solid tumor. These two main characteristics make attenuated Salmonella one of the most attractive vehicles for development of vaccine and also targeted cancer therapies. However, location of Salmonella prevents the process of antigen presentation. Salmonella Type III secretion system can be utilized to circumvent this problem because this system secretes the protein it encoded outside the cells. Heat shock protein 70 (Hsp70) is referred to as an “immunochaperone” for its capacity to elicit tumor‐specific adaptive immune responses in the form of Hsp70‐TAA (tumor associated antigen) complex. Hsp70 facilitates the cross‐presentation of exogenous antigens through its receptor on antigen‐presenting cells and therefore activates an antigen‐specific cytotoxic T lymphocyte (CTL) response, which can directly contribute to potent anti‐tumor immunity. Here, we designed a novel therapeutic vaccine utilizing the type III secretion system and Hsp70 to deliver and present the tumor‐specific antigen. This live recombinant bacteria vaccine, when administrated orally, successfully broke the immune tolerance, induced a specific CTL response against tumor cells, and therefore revealed protective and therapeutic effects against generation and growth of B16F10 melanoma in C57BL/6J mice. (Cancer Sci 2010; 101: 2621–2628)
Incorporation of multicellular spheroids into 3‐D polymeric scaffolds provides an improved tumor model for screening anticancer drugs
Authors: Ho Won Jin , Pham Edward A. , Kim Jun W. , Ng Christopher W. , Kim Jae H. , Kamei Daniel T. , Wu Benjamin M.
Published: August 2010

Development of cancer therapeutics requires a thorough evaluation of drug efficacy in vitro before animal testing and subsequent clinical trials. Three‐dimensional (3‐D) in vitro models have therefore been investigated for drug screening. In this study, we have developed a novel in vitro model in which multicellular aggregates, or spheroids, were incorporated into 3‐D porous scaffolds. Drug resistance assays showed that spheroid‐seeded scaffolds have much higher drug resistance than monolayer cultures, spheroids on flat substrates, or scaffolds seeded with dispersed cells. Furthermore, spheroid‐seeded scaffolds demonstrated higher lactate production leading to acidosis, and higher expression of angiogenic factors. These data suggest that the spheroid‐seeded 3‐D scaffolds might serve as a useful in vitro system for screening cancer therapeutics. (Cancer Sci 2010; 101: 2637–2643)
CH05‐10, a novel indinavir analog, is a broad‐spectrum antitumor agent that induces cell cycle arrest, apoptosis, endoplasmic reticulum stress and autophagy
Authors: You Jianlan , He Zhengxiang , Chen Lili , Deng Gang , Liu Wei , Qin Li , Qiu Fayang , Chen Xiaoping
Published: August 2010

Indinavir, a human immunodeficiency virus (HIV) protease inhibitor, inhibits the growth of tumor cells in vivo but does not show any cytotoxicity against cancer cells in vitro. To optimize the anticancer activity of indinavir, two novel analogs, CH05‐0 and CH05‐10, were synthesized. CH05‐10 was much more cytotoxic than indinavir and had similar cytotoxicity to nelfinavir, the one with the best anticancer activities among all HIV protease inhibitors examined. For 14 cell lines representing 10 different types of human malignancies, the 50% inhibitory concentration (IC50) values of CH05‐10 are in the range of 4.64–38.87 μM. Further detailed studies using the lung cancer cell line A549 as the model system showed that the effect of CH05‐10 on the A549 cell line is both time‐ and dose‐dependent. The CH05‐10 treatment not only induced cell cycle arrest at G1 and caused caspase‐dependent apoptosis, but also resulted in caspase‐independent death via the induction of endoplasmic reticulum stress and unfolded protein response. These findings demonstrate that CH05‐10, a novel indinavir analog, is a potent anticancer agent with pleiotropic effects. (Cancer Sci 2010; 101: 2644–2651)
Role of ZNF143 in tumor growth through transcriptional regulation of DNA replication and cell‐cycle‐associated genes
Authors: Izumi Hiroto , Wakasugi Tetsuro , Shimajiri Shohei , Tanimoto Akihide , Sasaguri Yasuyuki , Kashiwagi Eiji , Yasuniwa Yoshihiro , Akiyama Masaki , Han Bin , Wu Ying , Uchiumi Takeshi , Arao Tokuzo , Nishio Kazuto , Yamazaki Ryuta , Kohno Kimitoshi
Published: August 2010

The cell cycle is strictly regulated by numerous mechanisms to ensure cell division. The transcriptional regulation of cell‐cycle‐related genes is poorly understood, with the exception of the E2F family that governs the cell cycle. Here, we show that a transcription factor, zinc finger protein 143 (ZNF143), positively regulates many cell‐cycle‐associated genes and is highly expressed in multiple solid tumors. RNA‐interference (RNAi)‐mediated knockdown of ZNF143 showed that expression of 152 genes was downregulated in human prostate cancer PC3 cells. Among these ZNF143 targets, 41 genes (27%) were associated with cell cycle and DNA replication including cell division cycle 6 homolog (CDC6), polo‐like kinase 1 (PLK1) and minichromosome maintenance complex component (MCM) DNA replication proteins. Furthermore, RNAi of ZNF143 induced apoptosis following G2/M cell cycle arrest. Cell growth of 10 lung cancer cell lines was significantly correlated with cellular expression of ZNF143. Our data suggest that ZNF143 might be a master regulator of the cell cycle. Our findings also indicate that ZNF143 is a member of the growing list of non‐oncogenes that are promising cancer drug targets. (Cancer Sci 2010; 101: 2538–2545)
Dietary and oral hygiene intervention in secondary school pupils
Authors: Anttonen Vuokko , Seppä Liisa , Niinimaa Ahti , Hausen Hannu
Published: August 2010

Background

To enhance the well‐being of secondary school pupils by improving their eating habits, especially school‐based eating, a joint project, including oral health intervention, was conducted during the academic year 2007–2008.

Aim

The aim was to study the effect of a dietary intervention on schoolchildren’s eating habits and laser fluorescence (LF) values of teeth.

Methods

Twelve schools in three cities, Finland, were randomly assigned to be intervention and control schools. Two of the intervention schools were further assigned in the instruction of oral hygiene. In 2007 and 2008, the pupils (n = 739 and 647, respectively) answered a questionnaire on dietary and oral health habits, and LF values on the occlusal surfaces of molars and premolars were determined.

Results

The frequency of eating a warm meal and drinking water at school to quench thirst increased in the intervention schools but decreased in the control schools (P < 0.001 and P = 0.005, respectively). LF values in molars decreased in schools with dietary intervention only (P = 0.024).

Conclusions

The 1‐year dietary intervention was long enough to show improvement in eating habits and in habits for quenching thirst, and some decrease in the LF values of molars.
Association between interdental plaque acidogenicity and caries risk at surface level: a cross sectional study in primary dentition
Authors: Cagetti Maria Grazia , Campus Guglielmo , Sale Silvana , Cocco Fabio , Strohmenger Laura , Lingström Peter
Published: August 2010

Background

In schoolchildren the most commonly decayed primary teeth are molars affecting proximal adjacent surfaces especially.

Aim

To determine whether a more acidic plaque in response to sucrose challenge is detected in children with more carious lesions.

Design

Plaque pH measurements, using the microtouch technique, were carried out in interproximal spaces between primary molars, in 157 high caries risk children (314 sites and caries status of the 628 proximal surfaces recorded). The area under the curve (AUC5.7 and AUC6.2) was analyzed.

Results

The AUC5.7 and the AUC6.2 showed a statistically significant difference between plaque adjacent to proximal surfaces with or without caries. Differences for AUC5.7 and AUC6.2 were recorded between one decayed surface compared to two decayed surfaces (P < 0.01) whereas a statistical significant difference was only observed for AUC5.7, when the areas under the curve were obtained near one decayed surface compared to two sound surfaces (P = 0.04).

Conclusions

The higher acidogenicity of the dental plaque found in presence of a proximal carious lesion in primary maxillary molars represents an additional risk factor for the adjacent surface. This finding may help clinicians in treatment decisions.
Causes behind insect folivory patterns in latitudinal gradients
Authors: Björkman Christer , Berggren Åsa , Bylund Helena
Published: August 2010

1. Adams and Zhang recently published one of the best studies so far of patterns of insect folivory along a latitudinal (climatic) gradient. They show clear negative trends in foliage loss in relation to temperature for certain groups of insect herbivores.

2. Although their suggestion that the plant–herbivore interaction may be more important in cooler climates could be valid, they did not bring up the complementary explanation that interactions between predators and herbivores could also vary with climate. There are indications that insect natural enemies may respond more positively than insect herbivores to an increase in temperature. We argue that higher predator pressure in warmer climates may partly explain the patterns observed by Adams and Zhang.

3. Synthesis.To further develop the important research concerning herbivory in a changing climate, both theoretically and empirically, plant ecologists and entomologists would mutually benefit from joining forces.
The role of dispersal in shaping plant community composition of wetlands within an old‐growth forest
Authors: Flinn Kathryn M. , Gouhier Tarik C. , Lechowicz Martin J. , Waterway Marcia J.
Published: August 2010

1. Dispersal ability can influence the importance of dispersal relative to other processes organizing metacommunities, such as species sorting among habitats along environmental gradients.

2. We compare plants with different dispersal modes and habitat affinities, evaluating the roles of environmental and spatial controls on plant community composition in 128 wetlands within 10 km2 of old‐growth maple–beech forest in southern Québec, Canada.

3. We address two hypotheses. First, we ask whether species with short‐distance dispersal mechanisms are more dispersal‐limited than species with adaptations for long‐distance dispersal. Second, because wetland habitats are more fragmented than upland habitats in this forested area, we test the hypothesis that wetland species are more dispersal‐limited than upland species growing in the same wetlands (e.g. on hummocks within a swamp).

4. Variation partitioning based on constrained ordinations showed that the distributions of species with short‐distance dispersal mechanisms related more strongly to spatial factors than the distributions of long‐distance dispersers, supporting the interpretation that these species are more dispersal‐limited. The distributions of short‐distance dispersers also showed finer‐scale spatial patterns than the distributions of long‐distance dispersers.

5. Distributions of wetland species related more strongly to environmental conditions than the distributions of upland species growing in the same wetlands, suggesting that wetland species are actually less dispersal‐limited than upland species. Wetland and upland species had similar patterns of spatial variation in community composition.

6. Synthesis. The processes of dispersal limitation and species sorting along environmental gradients have differential importance to plants that grow within the same communities, but differ in dispersal ability and habitat affinity. This result emphasizes the impact of dispersal ability on the organization of metacommunities.
Mixed oligopoly and spatial agglomeration: a comment
Authors: Cárdenas Oscar J
Published: August 2010

Abstract.  This paper extends Matsushima and Matsumura (2003) by incorporating a large production cost difference between public and private firms in a quantity setting spatial mixed oligopoly. The public and private firms first choose their locations in a linear market and then compete in quantities. It is shown that for a significant inefficiency of the public firm, all firms (including both public and private firms) agglomerate at the market centre.
Do tariff reductions affect the wages of workers in protected industries? Evidence from the Canada‐U.S. Free Trade Agreement
Authors: Townsend James
Published: August 2010

Abstract.  In this paper, I use Canadian micro‐data on individual workers to investigate the effect on wages of the tariff reductions mandated by the Canada‐U.S. Free Trade Agreement (CUSFTA). The literature on industry wage premia has revealed that the industry of employment is an important determinant of a worker's wage. My findings indicate that relative wages fell in those industries that faced the deepest tariff cuts. This effect was experienced regardless of whether or not workers belonged to a union, suggesting that CUSFTA reduced the returns to industry‐specific human capital for those workers in the mostly heavily affected industries.
Snow removal auctions in Montreal: costs, informational rents, and procurement management
Authors: Flambard Véronique , Lasserre Pierre , Mohnen Pierre
Published: August 2010

Abstract. Using semi‐parametric and non‐parametric estimation techniques, we infer cost distributions and informational rents from 457 bids for snow removal contracts offered for tender by the City of Montreal between 1990 and 1998. Bids and costs have decreased over the sample period, while rents remained relatively constant. The City deserves credit for these results, as it has succeeded in exploiting economies of scale and triggering innovations while maintaining competition. Further, it has been successful in adjusting its reserve prices to keep up with the decreasing cost of snow removal.
Tax incentives and fertility in Canada: quantum vs tempo effects
Authors: Parent Daniel , Wang Ling
Published: August 2010

Abstract.  Using inter‐jurisdictional differences in the implementation of the Family Allowance Program in Canada in the mid‐1970s, this paper first shows that Quebec families with two or more children prior to being exposed to the program responded quite strongly to the added incentives in the short run relative to women in other Canadian provinces. Tracking down the cohorts across Censuses, we find that the same group of Quebec families subsequently showed a decrease in fertility relative to the rest of Canada, leaving ultimate family size unaffected. These results are consistent with the program having generated only a timing effect.
The tale of the tails: Canadian income inequality in the 1980s and 1990s
Authors: Frenette Marc , Green David A. , Milligan Kevin
Published: August 2010

Abstract.  We present new evidence on levels and trends in after‐tax income inequality in Canada between 1980 and 2000. We argue that existing data sources may miss changes in the tails of the income distribution, and that many of the changes in the income distribution have been in the tails. For this reason, we turn to an alternative source. In particular, we construct data on after‐tax and transfer income using Census files augmented with predicted taxes based on information available from administrative tax data. Using these data, we find that Canadian after‐tax inequality levels are substantially higher than has been previously recognized, primarily because income levels are lower at the bottom of the distribution than in commonly used survey data. We also find larger long‐term increases in after‐tax income inequality and far more variability over the economic cycle. This raises interesting questions about the role of the tax and transfer system in mitigating both trends and fluctuations in market income inequality.
What drives provincial‐Canada yield spreads?
Authors: Booth Laurence , Georgopoulos George , Hejazi Walid
Published: August 2010

Abstract.  Although recent research has led to a deeper understanding of the factors determining yields on long‐term Canada bonds, there has been little corresponding work on provincial bonds. By using a carefully constructed new data set, we establish two important results. First, provincial fiscal positions (debt and deficits) are an important factor in determining yield spreads between provincial and Canada bonds. Second, we show that provincial bonds are a substitute for corporate debt, in that during recessionary ‘flights to quality’ their yields react like those on corporate bonds.
A rapid staining‐assisted wood sampling method for PCR‐based detection of pine wood nematode Bursaphelenchus xylophilus in Pinus massoniana wood tissue
Authors: Wang X. R. , Kong X. C. , Jia W. H. , Zhu X. W. , Ren L. L. , Mota M. M.
Published: August 2010

For reasons of unequal distribution of more than one nematode species in wood, and limited availability of wood samples required for the PCR‐based method for detecting pinewood nematodes in wood tissue of Pinus massoniana, a rapid staining‐assisted wood sampling method aiding PCR‐based detection of the pine wood nematode Bursaphelenchus xylophilus (Bx) in small wood samples of P. massoniana was developed in this study. This comprised a series of new techniques: sampling, mass estimations of nematodes using staining techniques, and lowest limit Bx nematode mass determination for PCR detection. The procedure was undertaken on three adjoining 5‐mg wood cross‐sections, of 0.5 × 0.5 × 0.015 cm dimension, that were cut from a wood sample of 0.5 × 0.5 × 0.5 cm initially, then the larger wood sample was stained by acid fuchsin, from which two 5‐mg wood cross‐sections (that adjoined the three 5‐mg wood cross‐sections, mentioned above) were cut. Nematode‐staining‐spots (NSSs) in each of the two stained sections were counted under a microscope at 100× magnification. If there were eight or more NSSs present, the adjoining three sections were used for PCR assays. The B. xylophilus– specific amplicon of 403 bp (DQ855275) was generated by PCR assay from 100.00% of 5‐mg wood cross‐sections that contained more than eight Bx NSSs by the PCR assay. The entire sampling procedure took only 10 min indicating that it is suitable for the fast estimation of nematode numbers in the wood of P. massonina as the prelimary sample selections for other more expensive Bx‐detection methods such as PCR assay.
Characterization of the sperm‐associated body and its role in the fertilization of the chicken Gallus domesticus
Authors: Rabbani Mohammad Golam , Sasanami Tomohiro , Mori Makoto , Yoshizaki Norio
Published: August 2010

The present paper aimed to characterize the substance forming the sperm‐associated body (SB), to find its producing sites, and to show its functions in the fertilization of chicken. The SB was found both in between the inner and outer layers of vitelline membranes around eggs and in the oviductal infundibulum. Material from which the SB is constructed (SB substance) was isolated from the vitelline membranes. It was a hydrophobic protein with a molecular size of 570 kDa. X‐ray microanalysis detected calcium in the aggregates of the SB substance. Immunofluorescence and immunoelectron microscopy showed that the substance was produced in secretory cells in the luminal epithelium of the oviductal infundibulum and was provided to the egg on and in its vitelline membrane. During incubation, the SB substance bound with spermatozoa in the posterior portion of their flagella. Holes and disks were found in the vitelline membranes of fertile eggs at a ratio of 1: 19–24. Over 94% of the holes were accompanied by SB. The presence of SB is necessary for fertile spermatozoa to make holes in the membrane and to enter the fertile egg.
Liver development and regeneration: From laboratory study to clinical therapy
Authors: Hata Shoji , Namae Misako , Nishina Hiroshi
Published: August 2010

The liver has an unusual capacity to regenerate after a loss of mass and function caused by surgical resection or toxic liver injury. Over the last 10 years there have been major advances in our understanding of the molecular and cellular mechanisms underlying liver development and regeneration. The numerous factors crucial to these phenomena have been identified mainly by using knockout mice. Forward‐genetics studies using zebrafish and medaka have also generated many mutants with liver disorders or defects in liver formation. Our goal is to translate knowledge gained from laboratory work and animal models into novel therapies for human liver diseases. Exciting progress has been achieved using human partial liver transplantation and autologous cell therapy.
Comparison of characteristics of cultured limbal cells on denuded amniotic membrane and fresh conjunctival, limbal and corneal tissues
Authors: Baharvand Hossein , Ebrahimi Marzieh , Javadi Mohammad Ali
Published: August 2010

This study aimed to evaluate proposed molecular markers related to eye limbal stem cells (SC) and to identify novel associated genes. The expression of a set of genes potentially involved in stemness was assessed in freshly prepared limbal, corneal and conjunctival tissues. PAX6, AC133, K12 and OCT4 were detected in all the tissues and p63+/K3−/K12+/Nodal+/Cx43+were expressed in conjunctival, p63−/K3+/K12+/Nodal−/Cx43+in corneal, and p63+/K3−/K12−/Nodal−/Cx43−in limbal tissues. Limbal explants were cultured on human amniotic membrane for 21 days. The cells expressed p63 but not K3, K12, Nodal and Cx43, however, the expression of K3, K12 and Cx43 was detected, and p63 and the high BrdU‐labeling index decreased with more culture. Ultrastructure analysis of the cultured cells showed typically immature organization of intracellular organelles and architecture. Our data suggest that limbal, corneal and conjunctival tissues are heterogeneous with some progenitors. Also, the expression of traditional SC markers may not be a reliable indicator of limbal SC and there is an increasing need to determine factor(s) involved in their stemness.
Hoxgenes in time and space during vertebrate body formation
Authors: Iimura Tadahiro , Pourquié Olivier
Published: August 2010

Vertebrae display distinct morphological features at different levels of the body axis. Links between collinearHoxgene activation and the progressive mode of body axis elongation have provided a fascinating blueprint of the mechanisms for establishing these morphological identities. In this review, we first discuss the regulation and possible role of collinearHoxgene activation during body formation and then highlight the direct role ofHoxgenes in controlling cellular movements during gastrulation, therefore contributing to body formation. Additional related research aspects, such as imaging of chromatin regulation, roles of micro RNAs and evolutional findings are also discussed.
Brachyury‐downstream notochord genes and convergent extension in Ciona intestinalis embryos
Authors: Hotta Kohji , Yamada Shigehiro , Ueno Naoto , Satoh Nori , Takahashi Hiroki
Published: August 2010

Formation of the chordate body is accomplished by a complex set of morphogenetic movements including convergent extension of notochord cells. In the ascidian Ciona intestinalis, Brachyury plays a key role in the formation of the notochord, and more than 30 Bra‐downstream notochord genes have been identified. In the present study, we examined the effects of functional suppression of nine Bra‐downstream notochord genes, which include Ci‐PTP, Ci‐ACL, Ci‐prickle, Ci‐netrin, Ci‐trop, Ci‐Noto3, Ci‐ASAK, Ci‐ERM and Ci‐pellino. When the function of the first two genes (Ci‐PTP and Ci‐ACL) was suppressed with specific morpholinos, the notochord cells failed to converge, while functional suppression of Ci‐prickle resulted in a failure of intercalation, and therefore the cells in these three types of embryo remained in the mid‐dorsal region of the embryo. Functional suppression of the next four genes (Ci‐netrin, Ci‐trop, Ci‐Noto3 and Ci‐ASAK) resulted in the partial defect of intercalation, and the notochord did not consist of a single row. In addition, when the function of the last two genes (Ci‐ERM and Ci‐pellino) was suppressed, notochord cells failed to elongate in the embryo, even though convergence/extension took place normally. These results indicate that many Bra‐downstream notochord genes are involved in convergence/extension of the embryo.
A Wnt3a variant participates in chick apical ectodermal ridge formation: Distinct biological activities of Wnt3a splice variants in chick limb development
Authors: Narita Tomohiro , Nishimatsu Shin‐ichiro , Wada Naoyuki , Nohno Tsutomu
Published: August 2010

Wnt/β‐catenin signaling is involved in the formation of the apical ectodermal ridge (AER) during vertebrate limb development. Although Wnt3a is a potent ligand for chick AER formation, whether chick Wnt3a can induce Fgf8 expression in chick embryos is unclear and the Wnt ligand involved in chick AER formation remains unknown. Here, we examined whether another Wnt3a isoform is expressed in the AER, and whether Wnt3 contributes to AER formation in chick as well as mouse embryos. We found that chick Wnt3 was not expressed in the presumptive limb ectoderm at the early stages of AER formation. Using 5′‐rapid amplification of cDNA ends, we isolated another chick Wnt3a transcript. This novel variant, Wnt3a variant 2, induced Fgf8 in the limb ectoderm and activated the β‐catenin pathway in vivo and in vitro. These data showed that Wnt3a variant 2 is an active form of chick Wnt3a that regulates chick AER formation.
Film tomography as a tool for three‐dimensional image construction and gene expression studies
Authors: Mitsumori Masayuki , Adachi Taro , Takayanagi Kazuho , Mito Taro , Ohuchi Hideyo , Kimura Shouichi , Kokubo Mitsunori , Higuchi Toshiro , Noji Sumihare
Published: August 2010

In order to observe three‐dimensional (3D) expression patterns of genes in whole animals, whole organs, or whole tissues, in situ hybridization (ISH) of many sections must be carried out and then used to construct a 3D image. For this purpose, we have developed an automatic microtome to prepare tissue sections with an adhesive film. We used commercially available film suitable for sectioning and ISH. We constructed a microtome and, after adherence of the film to a paraffin‐embedded tissue block, cut the block with a blade to prepare sections on film. Then, the sections‐on‐film were automatically set in a plastic frame that was the same size as a conventional glass slide. With this automatic microtome, tissue sections can be made for ISH or immunohistochemistry in addition to conventional hematoxylin and eosin staining without specific training. We demonstrate that we can construct 3D images of gene expression patterns obtained by ISH on sections prepared with this automatic microtome. We have designated this method as ‘Film Tomography (FITO)’.
Ultraconserved non‐coding sequence element controls a subset of spatiotemporal GLI3 expression
Authors: Paparidis Zissis , Abbasi Amir Ali , Malik Sajid , Goode Debbie K. , Callaway Heather , Elgar Greg , DeGraaff Esther , Lopez‐Rios Javier , Zeller Rolf , Grzeschik Karl‐Heinz
Published: August 2010

The zinc‐finger transcription factor GLI3 acts during vertebrate development in a combinatorial, context‐dependent fashion as a primary transducer of sonic hedgehog (SHH) signaling. In humans, mutations affecting this key regulator of development are associated with GLI3‐morphopathies, a group of congenital malformations in which forebrain and limb development are preferentially affected. We show that a non‐coding element from intron two of GLI3, ultraconserved in mammals and highly conserved in the pufferfish Fugu, is a transcriptional enhancer. In transient transfection assays, it activates reporter gene transcription in human cell cultures expressing endogenous GLI3 but not in GLI3 negative cells. The identified enhancer element is predicted to contain conserved binding sites for transcription factors crucial for developmental steps in which GLI3 is involved. The regulatory potential of this element is conserved and was used to direct tissue‐specific expression of a green fluorescent protein reporter gene in zebrafish embryos and of a beta‐galactosidase reporter in transgenic mouse embryos. Time, location, and quantity of reporter gene expression are congruent with part of the pattern previously reported for endogenous GLI3 transcription.
Disruption of imprinting and aberrant embryo development in completely inbred embryonic stem cell‐derived mice
Authors: Deng Tao , Kuang Ying , Zhang Dan , Wang Long , Sun Ruilin , Xu Guojiang , Wang Zhugang , Fei Jian
Published: August 2010

The completely embryonic stem (ES) cell‐derived mice (ES mice) produced by tetraploid embryo complementation provide us with a rapid and powerful approach for functional genome analysis. However, inbred ES cell lines often fail to generate ES mice. The genome of mouse ES cells is extremely unstable during in vitro culture and passage, and the expression of the imprinted genes is most likely to be affected. Whether the ES mice retain or repair the abnormalities of the donor ES cells has still to be determined. Here we report that the inbred ES mice were efficiently produced with the inbred ES cell line (SCR012). The ES fetuses grew more slowly before day 17.5 after mating, but had an excessive growth from day 17.5 to birth. Five imprinted genes examined (H19, Igf2, Igf2r, Peg1, Peg3) were expressed abnormally in ES fetuses. Most remarkably, the expression of H19 was dramatically repressed in the ES fetuses through the embryo developmental stage, and this repression was associated with abnormal biallelic methylation of the H19 upstream region. The altered methylation pattern of H19 was further demonstrated to have arisen in the donor ES cells and persisted on in vivo differentiation to the fetal stage. These results indicate that the ES fetuses did retain the epigenetic alterations in imprinted genes from the donor ES cells.
A new triple staining method for doublein situhybridization in combination with cell lineage tracing in whole‐mountXenopusembryos
Authors: Koga Masaaki , Kudoh Tomohiro , Hamada Yuki , Watanabe Masashi , Kageura Hiroshi
Published: August 2010

To analyze cell to cell interaction effects on cell differentiation, we developed a new triple staining method for doublein situhybridization with cell lineage tracing in whole‐mountXenopusembryos. The method provides high color contrast views, and also enabled us to examine inside the embryos. Wild‐type embryos whose blastomere(s) had been injected with a cell lineage tracer were cultured, fixed, hemisectioned when necessary, and first served for the doublein situhybridization, with two sequential chromogenic reactions. They were postfixed, and the labeled cells were retraced immunohistochemically. Finally, the pigment of the embryos was bleached to obtain a clear view. We applied this method to a blastomere transplantation experiment to examine whether the spatial gene expression patterns along the anteroposterior axis can be induced by cell to cell interactions. The presumptive organizer of a 32‐cell embryo was replaced by the labeled presumptive epidermis of another synchronous embryo. The resultant triple‐stained late gastrula showed quite similar anteroposterior expression patterns ofgscandXbrato those of a normal embryo in the axial mesoderm derived from the transplanted presumptive epidermis, indicating that cell to cell interactions had induced these patterns.
ORIGINAL ARTICLE: Comparison of the distribution of citations received by articles published in high, moderate, and low impact factor journals in clinical medicine
Authors: Falagas M. E. , Kouranos V. D. , Michalopoulos A. , Rodopoulou S. P. , Batsiou M. A. , Karageorgopoulos D. E.
Published: August 2010

Background: Whether the journal impact factor (JIF) indicator reflects the number of citations to an average article of a journal in different subject categories is controversial. We sought to further investigate this issue in general and internal medicine journals.

Methods: We selected to evaluate three journals of the above subject category, in each of three different JIF levels (high: 15.5–28.6, moderate: 4.4–4.9 and low: 1.6). Using the Scopus database, we retrieved the original research articles (after detailed screening) and review articles (as classified by Scopus) that were published in the selected journals in 2005 along with the number of citations they received in 2006 and 2007. We pooled the citations for articles of the same type in journals with the same JIF level into distinct variables.

Results: There was no marked association between the distribution of citations per article published in general medical journals and their JIF. All distributions studied were skewed to the right (higher number of citations). Specifically, 16–22% of the original research articles accounted for 50% of the total citations to this type of article for all three categories of studied journals; 34–37% of original research articles accounted for 75% of citations. The respective values for review articles were 12–18% and 29–39%.

Conclusion: The distribution of citations received by articles published in high, moderate and low impact factor journals in clinical medicine seems similar. The JIF is not an accurate indicator of the citations the average article receives; articles published in low impact factor journals can still be highly cited and vice versa.
BRIEF COMMUNICATION: Rapid and sequential desensitization to both aspirin and clopidogrel
Authors: Fernando S. L. , Assaad N. N. A.
Published: August 2010

Hypersensitivity reactions to aspirin and clopidogrel are 2.5% and 1%, respectively. Dual anti‐platelet therapy with these drugs is effective in preventing thrombosis following deployment of stents for cerebrovascular and cardiovascular syndromes. Desensitization therapy with both aspirin and clopidogrel may be required for patients undergoing stent implantation that have experienced hypersensitivity to these agents. We report the case of a 58‐year‐old woman who developed urticaria and angioedema following aspirin therapy for ischaemic cerebrovascular disease. She developed an identical reaction after clopidogrel was subsequently administered. Investigations revealed the presence of an internal carotid artery aneurysm that required deployment of a stent. Rapid desensitization to aspirin over 5.5 h followed 3 days later by rapid desensitization to clopidogrel over 2.5 h was successfully performed prior to stenting. After 4 months she has tolerated this dual anti‐platelet therapy without any adverse reaction. Rapid and sequential desensitization to both aspirin and clopidogrel can be successfully performed for patients who require stent deployment but have hypersensitivity to both these anti‐platelet agents.