bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrating marker assisted background analysis with foreground selection for identification of superior bacterial blight resistant recombinants in Basmati rice
Authors: Gopalakrishnan S. , Sharma R. K. , Anand Rajkumar K. , Joseph M. , Singh V. P. , Singh A. K. , Bhat K. V. , Singh N. K. , Mohapatra T.
Published: February 2008

Basmati rice is highly susceptible to bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae. Transfer of BB resistance genes from non‐Basmati sources to Basmati through cross‐hybridization requires strict monitoring for recovery of the desirable Basmati quality traits in the recombinants, which show complex inheritance pattern. We integrated background analysis using mapped microsatellite markers with foreground selection to identify superior lines that combine useful genes from a non‐Basmati BB resistance donor line IRBB55 with grain and cooking quality characteristics of the popular Basmati rice variety ‘Pusa Basmati 1’ (PB 1) employing backcross pedigree strategy. Foreground selection using linked markers ensured presence of two genes, xa13 and Xa21 for BB resistance from IRBB55, and the recurrent parent PB 1 allele for the waxy locus giving intermediate amylose content and maintainer allele at fertility restorer locus in the BC1F5 recombinants. Background analysis enabled selection of recombinants with recurrent parent genome to the extent of 86.3% along with the quality traits. The extent of introgression of non‐Basmati donor chromosome segments in the superior selections was estimated to be < 7.8 Mb and < 6.7 Mb in the xa13 and Xa21 linked genomic regions, respectively. Association mapping identified three quantitative trait loci, one each for 1000‐grain weight, fertile grains/panicle and cooked kernel length. The backcross‐pedigree breeding strategy facilitated recovery of additional desirable characteristics from the donor in some of the selections. The elite selection Pusa 1460‐01‐32‐6‐7‐67 with maximum genomic background and quality characteristics of the recurrent Basmati parent gave resistance reaction against BB, similar to that of the non‐Basmati resistant check variety and recorded an yield advantage of 11.9% over the best check in the multiplication agronomic trial in the Basmati growing region of India. This line, which has been released as a new variety in the name of ‘Improved Pusa Basmati 1’ for commercial cultivation in India, is an example of successful application of marker assisted selection to variety development.
MECHANISMS OF CYCLIC FATIGUE‐CRACK PROPAGATION IN A FINE‐GRAINED ALUMINA CERAMIC: THE ROLE OF CRACK CLOSURE
Authors: Gilbert C. J. , Ritchie R. O.
Published: February 2008

Abstract— Cyclic fatigue‐crack growth and resistance‐curve behavior have been studied in a fine‐grained (∼ 1 μm), high‐purity alumina. Specific emphasis is given to the mechanisms associated with crack growth that are controlled by the maximum (Kmax) and the alternating (ΔK), stress intensities and to the role of crack‐face interference (crack closure), which is known to be an important crack‐tip shielding mechanism in metal fatigue. Significant levels of subcritical crack growth were detected above a threshold stress intensity of ∼60% of the fracture toughness (Kc) in the alumina, with growth rates displaying a far larger dependence on Kmax compared to ΔK. The role of crack closure was examined using constant‐Kmax experiments, where the minimum stress intensity (Kmin) was maintained either above or below the stress intensity for crack closure (Kcl). Where Kmin< Kcl, growth rates were found to exhibit a lower dependence on ΔK, which was rationalized in terms of the frictional wear model for crack growth in grain‐bridging ceramics. It is concluded that crack closure, as conventionally defined, has little relevance as a crack‐tip shielding mechanism during fatigue‐crack growth in grain‐bridging ceramics, due to the low dependence of growth rates on ΔK compared to Kmax.
A STUDY OF RESIDUAL CAUSTICS GENERATED FROM FATIGUE CRACKS
Authors: Tomlinson R. A. , Patterson E. A.
Published: February 2008

Abstract— The method of caustics was used to determine the stress intensity factor of fatigue cracks in steel compact tension specimens. Under zero load a residual caustic was observed at the tip of a fatigue crack indicating the presence of a residual stress field. Caustics were generated at increasing static loads and the stress intensity factors were compared with those predicted by theory. It was found that the difference between each measured stress intensity factor and its corresponding theoretical value was a constant for the range of loads. This difference was shown statistically to be equal to the stress intensity factor determined from the residual caustic. The proposed mechanism for the formation of this residual caustic was probably due to crack tip plasticity effects and not due to crack closure. It was concluded that residual caustics can be measured to quantify crack tip behaviour in fatigue cracks and have been shown to be a useful tool in the measurement of residual stress fields.
A SINGULAR INTEGRAL EQUATION SOLUTION FOR THE LINEAR ELASTIC CRACK OPENING DISPLACEMENT OF AN ARBITRARILY SHAPED PLANE CRACK: PART I FINITE‐PART INTEGRAL SOLUTIONS
Authors: Mayrhofer K. , Fischer F. D.
Published: February 2008

Abstract— The aim of the paper is to compute the local crack face displacements of a linear elastic body containing an arbitrarily shaped plane crack. From the crack face displacements the local stress intensity factors can be derived.

The boundary value problem for a plane crack of arbitrary shape, embedded in a linear elastic medium, has been treated by several authors by the singular integral equation (SIE) approach. Their computations lead to a set of hyper‐singular integral equations for the Cartesian components of the unknown crack face displacements. To solve these equations the authors present a discretization procedure based on six‐node triangular finite elements. A total set of 24 finite‐part integrals defined over a triangular area can be developed. These 2D‐finite‐part integrals can be split into both a 1D‐regular and a 1D‐finite‐part‐integral by means of the polar coordinates so that they can be solved in closed form. Finally, the investigation of the SIEs is reduced to a discrete set of linear algebraic equations for the unknown nodal point values. The necessary steps will be demonstrated in detail. The derived closed‐form solutions will be offered in the text and in the appendices.
A SIMPLE TEST METHOD FOR ENERGY DISSIPATION RATE, CTOA AND THE STUDY OF SIZE AND TRANSFERABILITY EFFECTS FOR LARGE AMOUNTS OF DUCTILE CRACK GROWTH
Authors: Turner C. E. , Kolednik O.
Published: February 2008

Abstract— Simple extensions to the standard deep notch bend test procedure are suggested to allow the collection of data relevant to the energy dissipation rate, D, crack opening angle, COA, and J, all for arbitrarily large amounts of growth in extensive plasticity. The methods of analysis are detailed for real elastic‐plastic behaviour of a high strength low‐hardening type metal with a view to encouraging use on a wider range of materials. A proposal is made, and equations given, that the particular version of J used for an R‐curve derived from the area under the loading diagram, should correspond to the value of the far‐field integral, Jff.

The relationship between the global measure of COA that emerges from D and the local crack tip opening angle, CTOA, as used in computational studies, is established. Transferability of CTOA data is examined in the light of effects of size and configuration. An explicit rule of the form CTOA √G =f (material and configuration) is proposed for the modelling of ductile growth in finite element studies. It is applied to a set of data in the literature, for the variation of CTOA with size in the deep notch bend test and for the configurations, bending, double edge and centre cracked tension.
AN IMPROVED PROCEDURE FOR THE DETERMINATION OF HOT SPOT STRESSES IN TUBULAR JOINTS
Authors: Soh A. K.
Published: February 2008

Abstract— A conventional finite element method may show a weakness when determining the hot spot stress distributions in the brace/chord intersection region of offshore tubular joints. This is because the chosen element displacement functions do not implicitly satisfy the conditions which prevail on the free surfaces. A procedure has been proposed to modify the conventional finite element method so as to allow the hot spot stresses, which occur at the free boundary of the weld toe of tubular joints, to be determined with improved accuracy. The results obtained by this modified method are compared with both an experimental and a traditional finite element solution. The comparison shows that the modified solution is in better agreement with the experimental data as compared with the traditional solution.
THE CRACK INITIATION TOUGHNESS FOR BRITTLE FRACTURE OF SUPER DUPLEX STAINLESS STEEL
Authors: Marrow T. J. , Humphreys A. O. , Strangwood M.
Published: February 2008

Abstract— The occurrence of brittle stable crack growth before unstable fracture was demonstrated with the aid of heat‐tinting, for a ferritic matrix super duplex stainless steel which had been age‐hardened at 475°C. The critical crack tip opening displacement for stable crack growth, i.e. the crack initiation toughness, was measured using the direct‐current‐potential drop crack monitoring technique. A quantitative model for the effect of temperature and age‐hardening on the brittle crack initiation toughness is described.
Detection of novel Fibrobacter populations in landfill sites and determination of their relative abundance via quantitative PCR
Authors: McDonald James E. , Lockhart Robert J. , Cox Michael J. , Allison Heather E. , McCarthy Alan J.
Published: February 2008

Members of the bacterial genus Fibrobacter have long been considered important components of the anaerobic cellulolytic community in the herbivore gut, but their presence and activity in other environments is largely unknown. In this study, a specific polymerase chain reaction (PCR) primer set, targeting the 16S rRNA gene of Fibrobacter spp., was applied to community DNA from five landfill sites followed by temporal thermal gel electrophoresis (TTGE) analysis of cloned amplification products. Phylogenetic analysis of clone sequences indicated the presence of novel clusters closely related to the genus Fibrobacter. There are two named species, Fibrobacter succinogenes and F. intestinalis, and only two of the 58 sequenced clones were identified with them, and both were F. succinogenes. The clone sequences from landfill were recovered in five distinct clusters within the Fibrobacter lineage, and four of these were novel. Quantitative PCR (qPCR) assays of reverse‐transcribed community RNA from landfill leachates and rumen fluid samples indicated that the abundance of Fibrobacter spp. relative to total bacteria varied from 0.2% to 40% in landfill, and 21% to 32% in the rumen, and these data demonstrate that fibrobacters can be a significant component of the microbial community in landfill ecosystems. This is the first evidence for Fibrobacter spp. outside the gut ecosystem, and as the only cultivated representatives of this group are actively cellulolytic, their diversity and abundance points to a possible role in cellulose hydrolysis in landfill, and perhaps other anaerobic environments also.
Revealing biogeographical patterns by nonlinear ordinations and derived anisotropic spatial filters
Authors: Mahecha Miguel D. , Schmidtlein Sebastian
Published: February 2008

Aim  Spatial floristic and faunistic data bases promote the investigation of biogeographical gradients in relation to environmental determinants on regional to continental scales. Our aim was to extract major gradients in the distribution of vascular plant species from a grid‐based inventory (the German FLORKART data base) and relate them to long‐term precipitation and temperature records as well as soil conditions. We present an ordination technique capable of coping with this complex data array. The goal was also to sort out the influence of spatial autocorrelation, assuming floristic autocorrelation is anisotropic.

Location  Germany, at a spatial resolution of 6′ × 10′.

Methods  Isometric feature mapping (Isomap) was applied as a nonlinear ordination method. Isomap was coupled to ‘eigenvector‐based filters’ for generating spatial reference models representing spatial autocorrelation. What is novel here is that the derived filters are not based on the assumption of equidirectional autocorrelation. Instead, the so‐called ‘principal coordinates of anisotropic neighbour matrices’ build filters to test the influence of geographical vicinity in directions of high similarity among observations.

Results  The Isomap ordination of floristic data explained more than 95% of the data variance in six dimensions. The leading two dimensions (representing about 80% of the FLORKART data variance) revealed clear spatial gradients that could be related to independent effects of temperature, precipitation and soil observations. By contrast, the third and higher FLORKART dimensions were dominated by an antagonism of anisotropic spatial autocorrelation and soil conditions. A subsequent cluster analysis of the floristic Isomap coordinates educed the spatial organization of the floristic survey, indicating a considerable sampling bias.

Conclusions  We showed that Isomap provides a consistent methodical framework for both ordination and derived spatial filters. The technique is useful for tracing the often nonlinear features of species occurrence data to environmental drivers, taking into account anisotropic spatial autocorrelation. We also showed that sampling biases are a conspicuous source of variance in a frequently used floristic data base.
The methodological nettle: ICT and student achievement
Authors: Chandra Vinesh , Lloyd Margaret
Published: February 2008

A major challenge for researchers and educators has been to discern the effect of ICT use on student learning outcomes. This paper maps the achievements in Year 10 Science of two cohorts of students over two years where students in the first year studied in a traditional environment while students in the second took part in a blended or e‐learning environment. Using both quantitative and qualitative methods, the authors have shown that ICT, through an e‐learning intervention, did improve student performance in terms of test scores. They have also shown that this improvement was not global with the results for previously high‐performing female students tending to fall while the results for lower‐achieving boys rose. There was also a seeming mismatch between some students' affective responses to the new environment and their test scores. This study shows the complexity of ICT‐mediated environments through its identification and description of three core issues which beset the credibility of research in ICT in education. These are (1) ICT as an agent of learning, (b) site specificity, and (c) global improvement.
Enhancing systems‐thinking skills with modelling
Authors: Hung Woei
Published: February 2008

Systems thinking is an essential cognitive skill that enables individuals to develop an integrative understanding of a given subject at the conceptual and systemic level. Yet, systems thinking is not usually an innate skill. Helping students develop systems‐thinking skills warrants attention from educators. This paper describes a study examining the effects of utilising systems modelling as a cognitive tool in enhancing a group of graduate students' systems‐thinking skills. A significant improvement was observed in the systems‐thinking practises of the students. A theoretical rationale for enhancing systems‐thinking skills with modelling and the results of the study will be discussed.
Affective Flexibility
Authors: Cunningham William A. , Van Bavel Jay J. , Johnsen Ingrid R.
Published: February 2008

Although early research implicated the amygdala in automatic processing of negative information, more recent research suggests that it plays a more general role in processing the motivational relevance of various stimuli, suggesting that the relation between valence and amygdala activation may depend on contextual goals. This study provides experimental evidence that the relation between valence and amygdala activity is dynamically modulated by evaluative goals. During functional magnetic resonance imaging, participants evaluated the positive, negative, or overall (positive plus negative) aspects of famous people. When participants were providing overall evaluations, both positive and negative names were associated with amygdala activation. When they were evaluating positivity, positive names were associated with amygdala activity, and when they were evaluating negativity, negative names were associated with amygdala activity. Evidence for a negativity bias was found; modulation was more pronounced for positive than for negative information. These data suggest that the amygdala flexibly processes motivationally relevant evaluative information in accordance with current processing goals, but processes negative information less flexibly than positive information.
Does the mode of delivery predispose women to anal incontinence in the first year postpartum? A comparative systematic review
Authors: Pretlove SJ , Thompson PJ , Toozs‐Hobson PM , Radley S , Khan KS
Published: February 2008

Objectives  To assess if mode of delivery is associated with increased symptoms of anal incontinence following childbirth.

Design  Systematic review of all relevant studies in English.

Data sources  Medline, Embase, Cochrane Library, bibliographies of retrieved primary articles and consultation with experts.

Study selection and data extraction  Data were extracted on study characteristics, quality and results. Exposure to risk factors was compared between women with and without anal incontinence. Categorical data in 2 × 2 contingency tables were used to generate odds ratios.

Results  Eighteen studies met the inclusion criteria with 12 237 participants. Women having any type of vaginal delivery compared with a caesarean section have an increased risk of developing symptoms of solid, liquid or flatus anal incontinence. The risk varies with the mode of delivery ranging from a doubled risk with a forceps delivery (OR 2.01, 95% CI 1.47–2.74, P < 0.0001) to a third increased risk for a spontaneous vaginal delivery (OR 1.32, 95% CI 1.04–1.68, P = 0.02). Instrumental deliveries also resulted in more symptoms of anal incontinence when compared with spontaneous vaginal delivery (OR 1.47, 95% CI 1.22–1.78). This was statistically significant for forceps deliveries alone (OR 1.5, 95% CI 1.19–1.89, P = 0.0006) but not for ventouse deliveries (OR 1.31, 95% CI 0.97–1.77, P = 0.08). When symptoms of solid and liquid anal incontinence alone were assessed, these trends persisted but were no longer statistically significant.

Conclusion  Symptoms of anal incontinence in the first year postpartum are associated with mode of delivery.
A UNIQUE LIFE CYCLE AND PERENNATION IN A COLORLESS CHRYSOPHYTE SPUMELLA SP.1
Authors: Yubuki Naoji , Nakayama Takeshi , Inouye Isao
Published: February 2008

Life cycle and perennation of a colorless chrysophyte, Spumella sp., isolated from an ephemeral ditch were investigated. From a single resting cyst (statospore), only one nonmotile cell germinated. Shortly after germination, the cell generated flagella, started to swim, and formed a gelatinous sphere. The cell itself retained the ability to swim within the sphere. Cells fed on bacteria inhabiting the sphere and grew by longitudinal binary cell division very rapidly. The gelatinous sphere gradually enlarged as the number of cells increased. When it reached maximum size (∼500 μm in diameter), the gelatinous substance of the sphere weakened, and the sphere gradually broke into several pieces, forming cleavages between them. Cells swam away through the cleavages. Five to ∼40 swimming cells soon gathered and formed a swarm. In the swarm, some cells cannibalized other sibling cells and enlarged, resulting in giant cells that were two to three times larger in diameter than ordinary cells. The giant cells soon started statospore formation. Statospore formation was independent of any changes of environmental factors, such as increase or decrease in temperature or changes in nutrient or light levels, which are known to induce resting‐cyst formation in other groups of algae and protists. Statospore formation started when cells divided 15 to 16 times after germination. This is congruent with the idea that statospore formation in planktonic chrysophytes directly depends on cell density. An extraordinarily high growth rate and cannibalism involved in the initiation of statospore formation are interpreted as adaptations to achieve the perennation in ephemeral aquatic environments.
Nerve growth factor blocks thapsigargin‐induced apoptosis at the level of the mitochondrion viaregulation of Bim
Authors: Szegezdi E. , Reed Herbert K. , Kavanagh E. T. , Samali A. , Gorman A. M.
Published: February 2008

This study examined how the neurotrophin, nerve growth factor (NGF), protects PC12 cells against endoplasmic reticulum (ER) stress‐induced apoptosis. ER stress was induced using thapsigargin (TG) that inhibits the sarcoplasmic/ER Ca2+‐ATPase pump (SERCA) and depletes ER Ca2+ stores. NGF pre‐treatment inhibited translocation of Bax to the mitochondria, loss of mitochondrial transmembrane potential, cytochrome c release, activation of caspases (−3, −7 and −9) and apoptosis induction by TG. Notably, TG also caused a marked induction of Bimel mRNA and protein, and knockdown of Bim with siRNA protected cells against TG‐induced apoptosis. NGF delayed the induction and increased the phosphorylation of Bimel. NGF‐mediated protection was dependent on phosphatidylinositol‐3 kinase (PI3K) signalling since all above apoptotic events, including expression and phosphorylation status of Bimel protein, could be reverted by the PI3K inhibitor LY294002. In contrast, NGF had no effect on the TG‐mediated induction of the unfolded protein response (increased expression of Grp78, GADD34, splicing of XBP1 mRNA) or ER stress‐associated pro‐apoptotic responses (induction of C/EBP homologous protein [CHOP], induction and processing of caspase‐12). These data indicate that NGF‐mediated protection against ER stress‐induced apoptosis occurs at the level of the mitochondria by regulating induction and activation of Bim and mitochondrial translocation of Bax.
The Future of Chinese Management Research: A Theory of Chinese Management versus A Chinese Theory of Management
Authors: Barney Jay B. , Zhang Shujun
Published: February 2008

Two approaches to the evolution of Chinese scholarship are possible. The first – developing a theory of Chinese management – focuses on applying and refining theories developed elsewhere in a Chinese context. In this sense, the emergence of the Chinese economy represents an important natural experiment for the test and refinement of general management theories. The second – developing a Chinese theory of management – focuses on creating explanations for the existence of Chinese management phenomena that are uniquely Chinese. This approach rejects a research agenda created by Western scholars in favour of a research agenda created by Chinese scholars in order to understand Chinese phenomena. The implications of choosing either of these approaches for the future of Chinese management research and possible relationships between them are discussed.
Narrative Methods and Children: Theoretical Explanations and Practice Issues
Authors: Bennett Lorna
Published: February 2008

TOPIC:  The Narrative approach is an innovative way of working with children and adolescents experiencing mental health problems. This approach can be effectively integrated with the expressive arts and other nonverbal ways of accessing the life world of children. In addition, the approach promotes respect for and collaboration with the child in working towards healing and growth.

PURPOSE:  In this paper core features of the narrative approach are described; the theoretical and philosophical and evidence base for this approach as well as its congruence with the special nature and needs of children will be explored. Finally, the benefits and challenges of this approach in relation to a specific clinical situation will be highlighted.

SOURCES USED:  Published literature and the author's clinical experiences.

CONCLUSION:  Narrative methods are ideally suited for addressing needs of children experiencing mental health problems and can enhance therapeutic effectiveness. Some of the challenges associated with its use include: finding creative ways to apply specific narrative concepts and methods with diverse clinical issues/problems; learning to collaborate with children and respect them as experts in their own lives; and shifting the nursing focus from a problem‐focused orientation to a strength‐oriented and child‐centered approach.
Modification of Granular Corn Starch with 4‐α‐Glucanotransferase from Thermotoga maritima: Effects on Structural and Physical Properties
Authors: Oh E.J. , Choi S.J. , Lee S.J. , Kim C.H. , Moon T.W.
Published: February 2008

ABSTRACT:  Corn starch was converted using α‐1,4‐glucanotransferase from Thermotoga maritima (TmαGT), a hyperthermophilic bacterium, without inducing gelatinization, and the structural changes and physical properties of the modified starches were investigated. Enzyme modification was induced at 65 °C for 8, 16, or 24 h, and the morphology of the modified starches was observed with light and scanning electron microscopy. Granule integrity was mostly maintained after enzyme treatment, although some granules were partially fragmented as evidenced by enlarged surface pores and some cracks. The modified starches had lower apparent amylose levels than raw starch. The molecular weights of amylose and amylopectin molecules in the treated starches were lower than those of raw starch, and the amount of branched molecules, which had much lower molecular weights, also increased in the treated starches. The chain‐length distribution of amylopectin showed an increased number of shorter branched chains. The modified starches showed a wider melting temperature range and a lower melting enthalpy than that of raw starch. The X‐ray diffraction pattern of the modified starches showed typical A‐type starch peaks, but the relative crystallinities were lower than that of raw starch. The solubility and paste clarity of the modified starches were much higher than those of raw starch. The modified starch gels maintained their rigidity over the whole frequency range tested and showed thermoreversibility between 4 and 75 °C. These results suggest that TmαGT can be used to produce granular corn starch, which contains amylose and amylopectin having lower molecular weights and a thermoreversible gelation property.
Speed of induction of anaesthesia in dogs administered halothane, isoflurane, sevoflurane or propofol in a clinical setting
Authors: Pottie RG , Dart CM , Perkins NR
Published: February 2008

Objective To compare the speed and quality of induction of general anaesthesia using three different inhalant agents and one intravenous agent, in healthy dogs undergoing desexing surgery.

Materials and methods Less excitable dogs were not premedicated; others were premedicated with intramuscular acepromazine and morphine. Anaesthesia induction protocol was randomly assigned, with halothane, isoflurane or sevoflurane delivered by mask, or propofol delivered intravenously. Maximum vaporiser settings were used for inhalant inductions. Induction of anaesthesia was considered complete at the time of endotracheal intubation. Quality of induction was scored by the administering veterinarian.

Results Seventy‐one dogs were enrolled. Twenty‐four received no premedication and 47 received premedication. Isoflurane inductions were significantly faster than halothane inductions (2.86 ± 0.25 vs 3.71 ± 0.22 min; mean ± SE, P = 0.013). Sevoflurane inductions (3.29 ± 0.24 min) were not significantly different from either halothane (3.71 ± 0.22 min, P = 0.202) or isoflurane inductions (2.86 ± 0.25 min, P = 0.217). Induction with propofol (1.43 ± 0.13 min) was significantly faster than inhalant induction (P < 0.001 in each case). Premedication decreased the dose requirement and time to induction for dogs induced with propofol, but did not significantly change the time to intubation for inhalant inductions. Dogs administered propofol and/or premedication were significantly more likely to have an excellent quality of induction, but there was no difference between inhalant agents in terms of induction quality.

Conclusion Sevoflurane possesses chemical properties that should produce a more rapid induction of anaesthesia in comparison to halothane or isoflurane. However, in clinical practice patient related factors outweigh this improvement.
SPECTRA OF TRANSIENTS OF RIBOFLAVIN, LUMIFLAVIN AND LUMICHROME UNDER FLASH EXCITATION*
Authors: Terenin A. , Tachin V. , Shakhverdov P.
Published: February 2008

Abstract— Solutions of riboflavin and lumiflavin show under flash excitation in the presence of diphenylamine a reversible fading of their absorption bands with the appearance of new bands belonging to the cation‐radical of diphenylamine and the semiquinone of the flavin. Lumichrome under similar conditions abstracts a H‐atom from diphenylamine.
Genetic variation and productivity of Populustrichocarpa and its hybrids. VII. Two-year survival and growth of native black cottonwood clones from four river valleys in Washington
Authors: Dunlap J.M. , Heilman P. E. , Stettler R.F.
Published: February 2008

A common-garden study of Populustrichocarpa Torr. & Gray was initiated in 1985 when clonal material from 128 trees was collected from sites distributed along two mesic (Hoh and Nisqually) and two xeric (Dungeness and Yakima) river valleys. This material was grown for 1 year at Puyallup, Wash. In spring 1986, cuttings from this material were used to establish two replicate plantations, one at Puyallup and one at Wenatchee, Wash. Over the 2 year period, trees were assessed for survival, damage, and growth. Two-year survival was 86% at Puyallup and 59% at Wenatchee; survival was higher for mesic-origin trees at both sites. At Wenatchee, mortality was mainly due to a droughty soil and hot, dry climate in the first year, and damage was due to the tarnished plant bug (Lygus spp.), field voles (Microtus spp.), and grasshoppers (Family Acrididae). At both locations, Melampsoraoccidentalis Jacks. leaf rust was found mainly on trees originating from Yakima. Mean 2-year height and diameter at Puyallup were 457 cm and 40 mm, respectively; corresponding values at Wenatchee were 320 cm and 29 mm. At Puyallup, 2-year stem volume (diameter2 × height) decreased significantly in this order: Nisqually (13 500 cm3) = Hoh > Dungeness > Yakima (4700 cm3). Within the Nisqually trees, clones from lower, milder climate elevations grew more than those from the upper elevations. The reverse was true for the Yakima trees, presumably because the lower elevation trees are adapted to an arid climate and are very susceptible to Melampsora rust. At Wenatchee, high microsite heterogeneity masked much of the genetic variation. The genetic variance component (among rivers, sites, and clones) for stem volume at Puyallup increased from 27 to 51% over the second year. In analyses of each river valley, genetic components (elevational group and clone) were also high at 27–63%; however, for the Yakima trees, the elevational group variance (40%) was much larger than for the other valleys (0–7%) and suggests a steep selection gradient midway along the river transect.
Offspring–parent correlations for wood density of Pinustecunumanii between native and exotic environments
Authors: Dvorak W.S. , Wright J.A.
Published: February 2008

Seedlings from 83 mother trees of Pinustecunumanii (Schw.) Eguiluz & Perry, originating in a natural population in Belize, were established in two adjoining progeny tests at La Arcadia, Colombia. One 12-mm wood core was removed from each mother tree in Belize at seed collection, age 25–30 years, and 8-mm wood cores were taken from an average of nine trees per family in 8-year-old progeny trials in Colombia. Unextracted gravimetric wood density was obtained for juvenile wood (rings 1 to 10) and mature wood core segments (rings 11 to ≈25) for each parent tree as well as (juvenile wood) cores from the progeny. The wood density of progeny in Colombia averaged 377 kg/m3 versus 502 kg/m3 and 601 kg/m3 for the juvenile and mature wood of the parents, respectively. The correlation coefficient (r) for wood density between the mature wood of the parent trees and the juvenile wood of the progeny was 0.29 (significant at the p < 0.01 level). The estimated genetic gain in wood density as a result of selecting 1 in 20 trees in a progeny trial in Colombia was 8% when the estimated heritability (0.48) from sibling data was used, versus 5% when applying the offspring-parent estimate of heritability (0.27) from the correlation method.
Survival and growth of Pseudotsugamenziesii seedlings inoculated with biocide-treated soils at planting in a degraded clearcut
Authors: Colinas C. , Perry D. , Molina R. , Amaranthus M.
Published: February 2008

To determine the component(s) of transfer soils responsible for increased seedling survival and growth, we inoculated planting holes with forest, plantation, and clear-cut soils that were (i) treated with fertilizer to test for effects of nutrients; treated with biocides to test for effects of (ii) microarthropods or nematodes, (iii) protozoa, (iv) fungi, and (v) bacteria; (vi) pasteurized; (vii) Tyndallized; and (viii) untreated. Odds of survival were increased by inoculation with untreated plantation soils, but not if they were fertilized or treated with dimethoate + carbofuran (grazercide), fumagillin (protozoacide), or oxytetracycline + penicillin (bactericide). Addition of untreated forest soil did not increase survival. For all soils, survival odds were increased by captan (fungicide), pasteurization, and Tyndallization. Treatments affected seedling dry weights differently than survival. Untreated plantation and forest soil transfers increased dry weights whereas neither did when treated with dimethoate + carbofuran. Dry weights of seedlings given clear-cut soil were increased by fertilization, pasteurization, and Tyndallization of the soil; the latter two treatments also increased the number of short roots. We hypothesize that stimulation of seedling growth by soil transfers was related to an increased rate of nutrient mineralization due to microbivorous soil animals contained within the transfer soils. Soil transfers may have enhanced seedling survival by at least two mechanisms: (i) by providing a safe site for beneficial rhizosphere organisms to proliferate, free from competing organisms that have proliferated in the clear-cut soil; (ii) through volatile organic compounds that stimulated seedling root growth, especially ethylene, which previous studies have shown to be produced at significantly lower rates in soils of the clear-cut compared with adjacent forest soils. Further research is needed to distinguish between these possibilities.
Classification of cedar, aspen, and true fir trees as decayed versus sound
Authors: Lemay Valerie M. , Tait David E. , van der Kamp Bart J.
Published: February 2008

Trees are classed as decayed if there is structural damage as a result of internal decay and as sound otherwise. This classification is often performed on standing trees using tree and stand measurements to predict the class. For this study, three general rule systems were proposed and compared. Two different methods, discriminant analysis and classification-trees analysis, were used to derive the various rules. These rules were developed for three species, true fir (Abieslasiocarpa (Hook.) Nutt.), western red cedar (Thujaplicata Donn), and trembling aspen (Populustremuloides Michx.), growing in British Columbia (B.C.). The success of each of the three rules systems developed using each of the two analytical methods was evaluated using the misclassification error rates calculated for a reserved portion of the data available for each species (test data sets). The ease of using and interpreting the rules was also considered in the evaluation. The results indicated that the developed rules were reasonably accurate in predicting the class of trees in the test data sets. Results were more accurate for cedar and aspen than for fir. The use of classification-trees analysis to develop rules in recommended over the use of discriminant analysis. Misclassification error rates were similar for the two methods, but the dichotomous trees that result from classification-trees analysis are much easier to use and interpret.
Photosynthesis and canopy nutrition of four sugar maple forests on acid soils in northern Vermont
Authors: Ellsworth David S. , Liu Xuan
Published: February 2008

Canopy nutrition, leaf chlorophyll concentration, and leaf CO2 assimilation capacity (Amax) were examined in sugar maple (Acersaccharum Marsh.) trees exhibiting symptoms of crown dieback in four stands on acid soils (pH ≈ 4.0) in northern Vermont. Leaf CO2 assimilation capacity was measured on foliage from detached and rehydrated branches harvested from the upper portion of the canopy. Leaf calcium (Ca) and magnesium (Mg) concentrations were among the lowest reported for sugar maple in its natural range. Total leaf chlorophyll concentrations of canopy leaves were lowest on the sites exhibiting the lowest leaf nitrogen (N) and Ca, and CO2 assimilation capacity was correlated with chlorophyll concentration among canopy leaves from all sites. Strong linear relationships were observed between leaf CO2 assimilation capacity per unit leaf mass and leaf N (r2 = 0.60) as well as leaf Ca (r2 = 0.51) among the four sites. On the basis of the observed strong correlation between leaf Ca and leaf N (r2 = 0.64) and the lack of clear enhancement of leaf CO2 assimilation capacity in trees fertilized with base cations (K, Ca, and Mg), it appears that leaf CO2 assimilation capacity and leaf Ca may not necessarily be functionally related. However, since low leaf CO2 assimilation capacity and photosynthetic N-use efficiency were common in unfertilized trees with low Ca (Ca < 0.6%), CO2 assimilation processes in sugar maple on acid soils may be limited by N and Ca × Mg interactions. The strongly acidic nature of the soils in these stands and the magnitude of acidic deposition in the region may precondition sugar maple trees on some sites to levels of cation deficiency that may be associated with low CO2 assimilation in the forest canopy.
HSP70 and EndoG Modulate Cell Death by Heat in Human Skin Keratinocytes in vitro
Authors: Chinnathambi Sathivel , Tomanek-Chalkley Ann , Bickenbach Jackie R.
Published: February 2008

We examined how young and old keratinocytes died from heat stress in vitro. We found that keratinocyte cell death was not due to oxidative stress as neither Mn-SOD nor Cu-Zn-SOD was produced in either young or old heated keratinocytes. Instead, analysis of the anti-apoptotic factors, Bcl2 and HSP70, and the pro-apoptotic factors, caspase 3, caspase 8, Apaf-1, cytochrome c, AIF, and EndoG, indicated that keratinocyte cell death occurred via the caspase-independent EndoG apoptotic pathway. We found that both young and old keratinocytes died via the same pathway, and that we could specifically reduce both young and old keratinocyte death by addition of the EndoG inhibitor NEM. Further analysis suggested that the difference between young and old keratinocyte death was due to the synthesis of HSP70 protein, with the increase in response to heat more pronounced in young keratinocytes than in old keratinocytes. When we inhibited HSP70 by adding quercetin, death was increased in both young and old keratinocytes, but more so in old keratinocytes. These data suggest that old keratinocytes may die more readily than young keratinocytes when heated because they synthesize HSP70 at a lower efficiency. Such findings suggest that HSP70 production may be age-dependent.
A New System for Cultivation of Human Keratinocytes on Acellular Dermal Matrix Substitute with the Use of Human Fibroblast Feeder Layer
Authors: Xiao S. , Zhu S. , Ma B. , Xia Z.-F. , Yang J. , Wang G.
Published: February 2008

To improve the proliferative potential of human keratinocytes (HK) cultured on acellular dermal matrix (ADM), HK and mitomycin C-treated human fibroblasts (MMC-HF) were seeded onto ADM to form four types of composite skin: type I, HK were seeded onto the epidermal side of ADM; type II, both HK and MMC-HF were seeded onto the epidermal side; type III, MMC-HF were preseeded onto the dermal side of ADM, and then HK were seeded onto the epidermal side, and type IV, where MMC-HF were preseeded onto both sides, and then HK were seeded onto the epidermal side. Compared with type I and III, the proliferative potential of HK of type II and IV was significantly higher on day 3, 5, 7 and 9 in vitro. In type I and III, HK grew into one layer on day 7–9, while in type II and IV keratinocytes grew into a confluent monolayer by day 4–6. The adherence to ADM of HK in types II and IV was stronger than that in type I and III. The take rate of type II and IV composite skin was also significantly higher. In conclusion, when MMC-HF and HK were cocultured on the epidermal side of ADM, MMC-HF could serve as excellent feeder cells.
Myoblasts Isolated from Hypertrophy-Responsive Callipyge Muscles Show Altered Growth Rates and Increased Resistance to Serum Deprivation-Induced Apoptosis
Authors: Lavulo Lopeti T. , Uaesoontrachoon Kitipong , Mirams Michiko , White Jason D. , Cockett Noelle E. , Mackie Eleanor J. , Pagel Charles N.
Published: February 2008

Back and hind limb muscles of sheep paternally heterozygous for the callipyge single nucleotide polymorphism undergo extensive hypertrophy shortly after birth. We have established cell cultures from foetal semitendinosus and longissimus dorsi muscles of normal and callipyge animals. Cultures were assessed for rates of proliferation, cell death, myogenicity and DLK1 expression. Myoblasts from callipyge semitendinosus, but not longissimus dorsi muscles, proliferated faster than myoblasts isolated from normal semitendinosus muscle, and cells isolated from either callipyge muscle were more resistant to serum deprivation-induced apoptosis than equivalent cells isolated from normal individuals. Theseobservations indicate that there are intrinsic differences in the behaviour of isolated myoblasts, which are associated with their muscle and genotype of origin. As myoblasts are the cells responsible for hypertrophy of muscle fibres, the observed differences in cell growth may play a role in the hypertrophy of certain muscles in callipyge animals.
Serum High-Density Lipoprotein Cholesterol Levels and Mortality in Frail, Community-Living Elderly
Authors: Landi Francesco , Russo Andrea , Pahor Marco , Capoluongo Ettore , Liperoti Rosa , Cesari Matteo , Bernabei Roberto , Onder Graziano
Published: February 2008

Background: High-density lipoprotein (HDL) cholesterol has been hypothesized to be a reliable marker of frailty and poor prognosis among the oldest elderly. Objective: In the present study, we evaluate the impact of HDL cholesterol on the risk of all-cause mortality in a large population of frail octogenarians and nonagenarians living in a community. Methods: We analyzed data from the Aging and Longevity Study in the Sirente geographic area (ilSIRENTE Study), a prospective cohort study that collected data on all subjects aged 80 year and older living in a mountain community (n = 359). The main outcome measure was the relative hazard ratio of death after 2 years of follow-up for different levels of HDL cholesterol. Results: A total of 86 deaths (30 men and 56 women) occurred during 2 years of follow-up. Among men the mean HDL cholesterol level was 36.7 ± 7.6 mg/dl among those who died as compared with 43.4 ± 10.3 mg/dl among survivors (p = 0.001). Similarly, among women, the mean HDL cholesterol level was 42.2 ± 11.5 mg/dl among those who died as compared with 49.3 ± 14.9 mg/dl among survivors (p = 0.001). Adjusting for potential confounders, including markers of frailty, LDL cholesterol, and triglycerides, somewhat reduced the strength of the association between HDL cholesterol levels and mortality, but it remained statistically significant. Conclusions: Our results obtained from a representative sample of very old and frail elderly subjects expand the knowledge that high levels of HDL cholesterol are associated with better survival. These findings support the hypothesis of a strong implication of the lipoprotein metabolism in the process of living an extremely long life.
Two Clonal Cell Lines of Immortalized Human Corneal Endothelial Cells Show either Differentiated or Precursor Cell Characteristics
Authors: Valtink Monika , Gruschwitz Rita , Funk Richard H.W. , Engelmann Katrin
Published: February 2008

Access to primary human corneal endothelial cells (HCEC) is limited and donor-derived differences between cultures exacerbate the issue of data reproducibility, whereas cell lines can provide sufficient numbers of homogenous cells for multiple experiments. An immortalized HCEC population was adapted to serum-free culture medium and repeated cloning was performed. Clonally grown cells were propagated under serum-free conditions and growth curves were recorded. Cells were characterized immunocytochemically for junctional proteins, collagens, Na,K-ATPase and HCEC-specific 9.3.E-antigen. Ultrastructure was monitored by scanning and transmission electron microscopy. Two clonal cell lines, HCEC-B4G12 and HCEC-H9C1, could be isolated and expanded, which differed morphologically: B4G12 cells were polygonal, strongly adherent and formed a strict monolayer, H9C1 cells were less adherent and formed floating spheres. The generation time of B4G12 cells was 62.26 ± 14.5 h and that of H9C1 cells 44.05 ± 5.05 h. Scanning electron microscopy revealed that B4G12 cells had a smooth cell surface, while H9C1 cells had numerous thin filopodia. Both cell lines expressed ZO-1 and occludin adequately, and little but well detectable amounts of connexin-43. Expression of HCEC-specific 9.3.E-antigen was found commensurately in both cell lines, while expression of Na,K-ATPase α1 was higher in H9C1 cells than in B4G12 cells. B4G12 cells expressed collagen IV abundantly and almost no collagen III, while H9C1 cells expressed both collagens at reasonable amounts. It is concluded that the clonal cell line B4G12 represents an ideal model of differentiated HCEC, while H9C1 may reflect features of developing or transitional HCEC.
Temporomandibular Joint Loading Patterns Related to Joint Morphology: A Theoretical Study
Authors: Colombo Vera , Palla Sandro , Gallo Luigi M.
Published: February 2008

It is unclear which aspects of the temporomandibular joint (TMJ) anatomy and/or kinematics determine shape and location of disk-compressive areas (stress field). The aim of this study was a quantitative analysis of TMJ anatomy to predict stress field path direction. Twenty-five asymptomatic TMJs (12 females and 13 males, aged 20–38 years) were tracked during unloaded opening/closing cycles. All TMJs were magnetic resonance (MR) imaged, reconstructed and animated with the recorded kinematics. Quantitative morphological parameters were calculated and entered into cross-validated multivariate discriminant analysis. Stress field paths during jaw opening were classified as mediolateral (ML) in 14 (9 females and 5 males) and lateromedial (LM) in 11 joints (3 females and 8 males). Curvature and incongruence as well as the dorsoventral position of the condyle in the fossa showed statistically significant differences (Mann-Whitney U test, p < 0.05). A combination of the lateral incongruence, the distance from the posterior slope of the eminence as well as the maximum posterior sagittal curvature enabled to correctly predict the direction of stress field paths in 92% of cases. In particular, ML type joints had laterally more congruent condyles/fossae and condyles more distant from the posterior slope of the eminence than LM type joints. Within the limits of this study, TMJ morphology seems to determine stress field path patterns.