bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiovascular Risk in 26,008 European Overweight Children as Established by a Multicenter Database
Authors: I'Allemand Dagmar , Wiegand Susanna , Reinehr Thomas , Müller Jörg , Wabitsch Martin , Widhalm Kurt , Holl Reinhard ,   APV‐Study Group
Published: May 2008

Objective: Although the obesity epidemic is progressing in European children too, there is no consensus on the population‐specific prevalence of comorbidities or efficient diagnostic strategies. Therefore, weight‐related risk factors, their interrelationship, and association with biological parameters were assessed in a large group of overweight (OW) children, documented by an electronic database.

Methods and Procedures: Data of 26,008 children (age 12.6 ± 2.9 years, 56% females) presented for OW (BMI > 90th percentile) or obesity (>97th percentile) in 98 specialized centers were evaluated using a simple software (Adipositas Patienten Verlaufsbeobachtung (APV)) for standardized longitudinal documentation. After local anonymization, data were transmitted for central analysis including multiple logistic regression.

Results: A total of 5.9% of the children were normal weight, 41% obese (OB), and 37% extremely OB (>99.5th percentile, XXL; 41% of the girls). In 50%, at least one risk factor and in 11% a cluster of two were found, comprising increased blood pressure (BP): 35.4%, dyslipidemia: 32% (total cholesterol: 14.1%, low‐density lipoprotein (LDL)‐cholesterol: 15.8%, high‐density lipoprotein (HDL)‐cholesterol: 11.1%, triglycerides: 14.3%), impaired glucose tolerance (IGtT): 6.5% and suspicion of diabetes: 0.7%. The degree of OW was inversely associated with HDL‐cholesterol and directly with clustered risk factors, impaired glucose metabolism, increased BP and triglycerides (odds ratios (ORs) XXL vs. normal = 6.15, >10, 4.3, 3.0 and 2.5, respectively), but not with LDL‐cholesterol.

Discussion: In a very large cohort of young Europeans risk factors for cardiovascular (CV) diseases are frequently found, related to the degree of OW and tend to cluster, thus a comprehensive screening is justified in all OW or OB children. Electronic patient documentation is feasible in a large obesity care network.
Developmental Origins of Childhood Overweight: Potential Public Health Impact
Authors: Gillman Matthew W. , Rifas‐Shiman Sheryl L. , Kleinman Ken , Oken Emily , Rich‐Edwards Janet W. , Taveras Elsie M.
Published: May 2008

Several modifiable pre‐ and postnatal determinants of childhood overweight are known, but no one has examined how they influence risk of overweight in combination. We estimated the risk of overweight at age 3 years according to levels of maternal smoking during pregnancy, gestational weight gain, breastfeeding duration, and infant sleep duration. We studied 1,110 mother‐child pairs in Project Viva, a prospective prebirth cohort study. The main outcome measure was child overweight (BMI for age and sex ≥95th percentile) at age 3. We ran logistic regression models with all four modifiable risk factors as well as the covariates maternal BMI and education, child race/ethnicity, and household income. From the model, we obtained the estimated probability of overweight for each of the 16 combinations of the four risk factors. During pregnancy, 9.8% of mothers smoked and 50% gained excessive weight. In infancy, 73% mother‐child pairs breastfed for <12 m, and 31% of infants slept <12 h/day. Among the 3‐year‐old children in the cohort, 9.5% were overweight. In the prediction model, the estimated probability of overweight ranged from 0.06 among children exposed to favorable levels of all four risk factors, to 0.29 with adverse levels of all four. Healthful levels of four behaviors during early development predicted much lower probability of overweight at age 3 than adverse levels. Interventions to modify several factors during pregnancy and infancy could have substantial impact on prevention of childhood overweight.
Straightness as the Main Factor of the Hermann Grid Illusion
Authors: Geier János , Bernáth László , Hudák Mariann , Séra László
Published: May 2008

The generally accepted explanation of the Hermann grid illusion is Baumgartner's hypothesis that the illusory effect is generated by the response of retinal ganglion cells with concentric ON–OFF or OFF–ON receptive fields. To challenge this explanation, we have introduced some simple distortions to the grid lines which make the illusion disappear totally, while all preconditions of Baumgartner's hypothesis remain unchanged. To analyse the behaviour of the new versions of the grid, we carried out psychophysical experiments, in which we measured the distortion tolerance: the level of distortion at which the illusion disappears at a given type of distortion for a given subject. Statistical analysis has shown that the distortion tolerance is independent of grid-line width within a wide range, and of the type of distortion, except when one side of each line remains straight. We conclude that the main cause of the Hermann grid illusion is the straightness of the edges of the grid lines, and we propose a theory which explains why the illusory spots occur in the original Hermann grid and why they disappear in curved grids.
The Relationship Perceived between the Real Body and the Mirror Image
Authors: Bianchi Ivana , Savardi Ugo
Published: May 2008

We analyse here people's perception of their reflections in mirrors placed in different positions. In two experiments, participants looked at their mirror image, in a third experiment they looked at another person's image. In both cases they were asked to answer a series of questions about how the virtual body appeared relative to the real body, focusing on different aspects. In experiment 1, they were asked to decide whether the reflections were identical, similar, different, or opposite in terms of the global relationship, orientation, and lateralisation (left-right arm). In experiment 2 they were instructed to make simple gestures and to evaluate if the gestures in the reflection were identical, opposite, similar, or different from theirs. Results show that ‘identity’ was preferred when the mirror was in front, and ‘opposition’ was preferred when the mirror was below. When opposition was experienced, it was attributed mainly to the exocentric frame of reference. Egocentric left – right reversal was not a common experience, although it was reported more frequently when the mirror was in front. The different roles of the exocentric and egocentric frames of reference were further tested in experiment 3, in which the condition of an observer looking at another person's reflection was studied. Contrary to the emphasis on the egocentric frame of reference in the literature on the ‘mirror question’, results presented in this paper demonstrate the importance of the exocentric frame of reference in influencing how observers react to their reflections.
Can Tactile Stimuli Be Subitised? An Unresolved Controversy within the Literature on Numerosity Judgments
Authors: Gallace Alberto , Tan Hong Z , Spence Charles
Published: May 2008

There is a growing interest in the question whether the phenomenon of subitising (fast and accurate detection of fewer than 4–5 stimuli presented simultaneously), widely thought to affect numerosity judgments in vision, can also affect the processing of tactile stimuli. In a recent study, in which multiple tactile stimuli were simultaneously presented across the body surface, Gallace et al (2006 Perception35 247–266) concluded that tactile stimuli cannot be subitised. By contrast, Riggs et al (2006 Psychological Science17 271–275), who presented tactile stimuli to participants' fingertips, came to precisely the opposite conclusion, arguing instead that subitising does occur in touch. Here, we re-analyse the data from both studies using more powerful statistical procedures. We show that Riggs et al's error data do not offer strong support for the subitising account and, what is more, Gallace et al's data are not entirely compatible with a linear model account of numerosity judgments in humans either. We then report an experiment in which we compare numerosity judgments for stimuli presented on the fingertips with those for stimuli presented on the rest of the body surface. The results show no major differences between the fingers and the rest of the body, and an absence of subitising in either condition. On the basis of these observations, we discuss whether the purported existence of subitisation in touch reflects a genuine cognitive phenomenon, or whether, instead, it may reflect a bias in the interpretation of the particular psychometric functions that happen to have been chosen by researchers to fit their data.
Processing of the Müller-Lyer Illusion by a Grey Parrot (Psittacus Erithacus)
Authors: Pepperberg Irene M , Vicinay Jennifer , Cavanagh Patrick
Published: May 2008

Alex, a Grey parrot ( Psittacus erithacus) who identifies the bigger or smaller of two objects by reporting its color or matter using a vocal English label and who states “none” if they do not differ in size, was presented with two-dimensional Müller-Lyer figures (Brentano form) in which the central lines were of contrasting colors. His responses to “What color bigger/smaller?” demonstrated that he saw the standard length illusion in the Müller-Lyer figures in 32 of 50 tests where human observers would also see the illusion and reported the reverse direction only twice. He did not report the illusion when (a) arrows on the shafts were perpendicular to the shafts or closely approached perpendicularity, (b) shafts were 6 times thicker than the arrows, or (c) after being tested with multiple exposures—conditions that also lessen or eliminate the illusion for human observers. These data suggest that parrot and human visual systems process the Müller-Lyer figure in analogous ways despite a 175-fold difference in the respective sizes of their brain volumes. The similarity in results also indicates that parrots with vocal abilities like Alex's can be reliably tested on visual illusions with paradigms similar to those used on human subjects.
Short-term effects of wheat straw incorporation into paddy field as affected by rice transplanting time
Authors: Ma J. , Xu H. , Han Y. , Cai Z. C. , Yagi K.
Published: May 2008

Short-term effects of wheat straw incorporation into paddy field include stimulation of CH4 emissions, immobilisation of available N, suppression of rice growth, and accumulation of toxic materials. To study these short-term effects as affected by timing of rice transplantation, a field experiment was conducted at Dapu, China, in 2005. Two levels of wheat straw (0 and 3.75 t/ha) and 2 rice-transplanting times (normal and delayed) were adopted in this experiment. Methane emissions, concentrations of soil mineral N, dry matter accumulations, and grain yields were measured. Delayed rice transplantation had no effect on total CH4 emission from paddy fields incorporated with wheat straw (P > 0.05), but a significant effect on mineralisation of N (P < 0.05), in contrast to the net N immobilisation in the fields where seedlings were transplanted on the normal date. In paddy fields incorporated with wheat straw, delayed transplantation tended to promote rice growth and increase grain yield compared with transplantation on the normal date.
Water drawdown by radish (Raphanus sativus L.) multiple-root systems evaluated using computed tomography
Authors: Hamza M. A. , Anderson S. H. , Aylmore L. A. G.
Published: May 2008

Although measurements of water drawdown by single radish root systems have been previously published by the authors, further research is needed to evaluate water drawdown patterns in multiple-root systems. The objective of this study was to compare water transpiration patterns estimated using X-ray computed tomography (CT) with the traditional gravimetric method and to evaluate the effects of variably spaced multiple root systems on soil water content and corresponding water content gradients.
Water drawdown showed a dual pattern in which it increased rapidly when soil water content was high at the beginning of transpiration, then slowed down to an almost constant level with time as water content decreased. These results contrast with the single-root system wherein transpiration rates initially increased rapidly and then slowly increased with time. Water uptake estimated using the CT method was observed to be 27–38% lower than the gravimetrically estimated water uptake; this difference was attributed to lower water uptake for the upper 30 mm layer (CT measured) than lower layers due to differences in root density. However, good correlation (r = 0.97) was found between both measurement methods. The drawdown patterns for multiple root systems showed a convex shape from the root surface to the bulk soil, compared with a nearly linear shape for single roots. The water content drawdown areas and the drawdown distances for multiple root systems were found to be much larger than those corresponding to single radish roots. Differential water content gradients were observed for roots spaced at 15-mm distances compared with 3–4-mm distances. These differential gradients from the bulk soil towards the root-zone occurred probably creating localised water potential gradients within the root-zone, which moved water from between roots to root surfaces. The lowest water content values were located in the inter-root areas. The CT-scanned layer probably acted as one drawdown area with particularly higher water drawdown from the inter-root areas.
Noncanonical role of Hox14 revealed by its expression patterns in lamprey and shark
Authors: Kuraku Shigehiro , Takio Yoko , Tamura Koji , Aono Hideaki , Meyer Axel , Kuratani Shigeru
Published: May 2008

Hox
genes are arranged in uninterrupted clusters in vertebrate genomes, and the nested patterns of their expression define spatial identities in multiple embryonic tissues. The ancestral
Hox
cluster of vertebrates has long been thought to consist of, maximally, 13
Hox
genes. However, recently, Hox14 genes were discovered in three chordate lineages, the coelacanth, cartilaginous fishes, and amphioxus, but their expression patterns have not yet been analyzed. We isolated Hox14 cDNAs from the Japanese lamprey and cloudy catshark. These genes were not expressed in the central nervous systems, somites, or fin buds/folds but were expressed in a restricted cell population surrounding the hindgut. The lack of Hox14 expression in most of the embryonic axial elements, where nested
Hox
expressions define spatial identities, suggests a decoupling of Hox14 genes' regulation from the ancestral regulatory mechanism. The relaxation of preexisting constraint for collinear expression may have permitted the secondary losses of this
Hox
member in the tetrapod and teleost lineages.
Selfishness as second-order altruism
Authors: Eldakar Omar Tonsi , Wilson David Sloan
Published: May 2008

Selfishness is seldom considered a group-beneficial strategy. In the typical evolutionary formulation, altruism benefits the group, selfishness undermines altruism, and the purpose of the model is to identify mechanisms, such as kinship or reciprocity, that enable altruism to evolve. Recent models have explored punishment as an important mechanism favoring the evolution of altruism, but punishment can be costly to the punisher, making it a form of second-order altruism. This model identifies a strategy called “selfish punisher” that involves behaving selfishly in first-order interactions and altruistically in second-order interactions by punishing other selfish individuals. Selfish punishers cause selfishness to be a self-limiting strategy, enabling altruists to coexist in a stable equilibrium. This polymorphism can be regarded as a division of labor, or mutualism, in which the benefits obtained by first-order selfishness help to “pay” for second-order altruism.
Host and invader impact of transfer of the
clc
genomic island into
Pseudomonas aeruginosa
PAO1
Authors: Gaillard Muriel , Pernet Nataskha , Vogne Christelle , Hagenbüchle Otto , van der Meer Jan Roelof
Published: May 2008

Genomic islands, large potentially mobile regions of bacterial chromosomes, are a major contributor to bacteria evolution. Here, we investigated the fitness cost and phenotypic differences between the bacterium
Pseudomonas aeruginosa
PAO1 and a derivative carrying one integrated copy of the
clc
element, a 103-kb genomic island [and integrative and conjugative element (ICE)] originating in
Pseudomonas
sp. strain B13 and a close relative of genomic islands found in clinical and environmental isolates of
P. aeruginosa
. By using a combination of whole genome transcriptome profiling, phenotypic arrays, competition experiments, and biofilm formation studies, only few differences became apparent, such as reduced biofilm growth and fourfold stationary phase repression of genes involved in acetoin metabolism in PAO1 containing the
clc
element. In contrast, PAO1 carrying the
clc
element acquired the capacity to grow on 3-chlorobenzoate and 2-aminophenol as sole carbon and energy substrates. No fitness loss >1% was detectable in competition experiments between PAO1 and PAO1 carrying the
clc
element. The genes from the
clc
element were not silent in PAO1, and excision was observed, although transfer of
clc
from PAO1 to other recipient bacteria was reduced by two orders of magnitude. Our results indicate that newly acquired mobile DNA not necessarily invoke an important fitness cost on their host. Absence of immediate detriment to the host may have contributed to the wide distribution of genomic islands like
clc
in bacterial genomes.
Insulin signaling and FOXO regulate the overwintering diapause of the mosquito
Culex pipiens
Authors: Sim Cheolho , Denlinger David L.
Published: May 2008

The short day lengths of late summer program the mosquito
Culex pipiens
to enter a reproductive diapause characterized by an arrest in ovarian development and the sequestration of huge fat reserves. We suggest that insulin signaling and FOXO (forkhead transcription factor), a downstream molecule in the insulin signaling pathway, mediate the diapause response. When we used RNAi to knock down expression of the insulin receptor in nondiapausing mosquitoes (those reared under long day lengths) the primary follicles were arrested in a stage comparable to diapause. The mosquitoes could be rescued from this developmental arrest with an application of juvenile hormone, an endocrine trigger known to terminate diapause in this species. When dsRNA directed against FOXO was injected into mosquitoes programmed for diapause (reared under short day lengths) fat storage was dramatically reduced and the mosquito's lifespan was shortened, results suggesting that a shutdown of insulin signaling prompts activation of the downstream gene FOXO, leading to the diapause phenotype. Thus, the results are consistent with a role for insulin signaling in the short-day response that ultimately leads to a cessation of juvenile hormone production. The similarity of this response to that observed in the diapause of
Drosophila melanogaster
and in dauer formation of
Caenorhabditis elegans
suggests a conserved mechanism regulating dormancy in insects and nematodes.
A Raft-derived, Pak1-regulated Entry Participates in α2β1 Integrin-dependent Sorting to Caveosomes
Authors: Karjalainen Mikko , Kakkonen Elina , Upla Paula , Paloranta Heli , Kankaanpää Pasi , Liberali Prisca , Renkema G. Herma , Hyypiä Timo , Heino Jyrki , Marjomäki Varpu
Published: May 2008

We have previously shown that a human picornavirus echovirus 1 (EV1) is transported to caveosomes during 2 h together with its receptor α2β1 integrin. Here, we show that the majority of early uptake does not occur through caveolae. α2β1 integrin, clustered by antibodies or by EV1 binding, is initially internalized from lipid rafts into tubulovesicular structures. These vesicles accumulate fluid-phase markers but do not initially colocalize with caveolin-1 or internalized simian virus 40 (SV40). Furthermore, the internalized endosomes do not contain glycosylphosphatidylinositol (GPI)-anchored proteins or flotillin 1, suggesting that clustered α2β1 integrin does not enter the GPI-anchored protein enriched endosomal compartment or flotillin pathways, respectively. Endosomes mature further into larger multivesicular bodies between 15 min to 2 h and concomitantly recruit caveolin-1 or SV40 inside. Cell entry is regulated by p21-activated kinase (Pak)1, Rac1, phosphatidylinositol 3-kinase, phospholipase C, and actin but not by dynamin 2 in SAOS-α2β1 cells. An amiloride analog, 5-(N-ethyl-N-isopropanyl) amiloride, blocks infection, causes integrin accumulation in early tubulovesicular structures, and prevents their structural maturation into multivesicular structures. Our results together suggest that α2β1 integrin clustering defines its own entry pathway that is Pak1 dependent but clathrin and caveolin independent and that is able to sort cargo to caveosomes.
Encoding choosiness: female attraction requires prior physical contact with individual male scents in mice
Authors: Ramm Steven A , Cheetham Sarah A , Hurst Jane L
Published: May 2008

Scents, detected through both the main and vomeronasal olfactory systems, play a crucial role in regulating reproductive behaviour in many mammals. In laboratory mice, female preference for airborne urinary scents from males (detected through the main olfactory system) is learnt through association with scents detected through the vomeronasal system during contact with the scent source. This may reflect a more complex assessment of individual males than that implied by laboratory mouse studies in which individual variation has largely been eliminated. To test this, we assessed female preference between male and female urine using wild house mice with natural individual genetic variation in urinary identity signals. We confirm that females exhibit a general preference for male over female urine when able to contact urine scents. However, they are only attracted to airborne urinary volatiles from individual males whose urine they have previously contacted. Even females with a natural exposure to many individuals of both sexes fail to develop generalized attraction to airborne male scents. This implies that information gained through contact with a specific male's scent is essential to stimulate attraction, providing a new perspective on the cues and olfactory pathways involved in sex recognition and mate assessment in rodents.
Cell cycle control of telomere protection and NHEJ revealed by a ts mutation in the DNA-binding domain of TRF2
Authors: Konishi Akimitsu , de Lange Titia
Published: May 2008

TRF2 is a component of shelterin, the telomere-specific protein complex that prevents DNA damage signaling and inappropriate repair at the natural ends of mammalian chromosomes. We describe a temperature-sensitive (ts) mutation in the Myb/SANT DNA-binding domain of TRF2 that allows controlled and reversible telomere deprotection. At 32°C, TRF2ts was functional and rescued the lethality of TRF2 deletion from conditional TRF2F/− mouse embryonic fibroblasts (MEFs). When shifted to the nonpermissive temperature (37°C), TRF2ts cells showed extensive telomere damage resulting in activation of the ATM kinase and nonhomologous end-joining (NHEJ) of chromosome ends. The inactivation of TRF2ts at 37°C was rapid and reversible, permitting induction of short periods (3–6 h) of telomere dysfunction in the G0, G1, and S/G2 phases of the cell cycle. The results indicate that both the induction of telomere dysfunction and the re-establishment of the protected state can take place throughout interphase. In contrast, the processing of dysfunctional telomeres by NHEJ occurred primarily in G1, being repressed in S/G2 in a cyclin-dependent kinase (CDK)-dependent manner.
Self-renewal versus transformation: Fbxw7 deletion leads to stem cell activation and leukemogenesis: Figure 1.
Authors: Perry John M. , Li Linheng
Published: May 2008

Recent reports have demonstrated that specific tumor suppressors are important for both maintaining hematopoietic stem cell (HSC) quiescence and preventing leukemia development, suggesting a connection between these two activities. Matsuoka and colleagues (pp. 986–991) have further illustrated this theme by demonstrating that inactivation of the tumor suppressor Fbxw7 leads to HSC depletion by active cell cycling and the initiation of leukemia.
Epigenetic control: slow and global, nimble and local: Figure 1.
Authors: Cheng Christine S. , Johnson Tracy L. , Hoffmann Alexander
Published: May 2008

The regulation of gene expression involves multiple levels of control, from those that are inheritable to those that are highly responsive to environmental changes. In this issue of Genes & Development, Dong and colleagues (pp. 1159–1173) demonstrate that the dynamically controlled immune response transcription factor NF-κB may, in fact, have a role in regulating heterochromatin and gene expression at large distances from its actual target sequences and genes.
Alkaline Phosphatase Treatment of Phosphopeptides: On-Probe Dephosphorylation after MALDI-MS Analysis
Authors: Steen Hanno , Stensballe Allan , Jensen Ole N.
Published: May 2008

INTRODUCTION

The use of the enzyme alkaline phosphatase allows identification of phosphopeptides in a mixture of predominantly nonphosphopeptides. Using a MALDI-MS instrument, the masses of peptides are acquired both before and after alkaline phosphatase treatment, which removes phospho-moieties from serine, threonine, and/or tyrosine. (Any peptide whose mass decreases by 80 Da, or a multiple thereof, is a phosphopeptide.) An advantage of using MALDI-MS for these experiments is that the peptide ions produced tend to be singly charged rather than multiply charged (as with ESI), thus making the interpretation easier. This protocol describes on-probe dephosphorylation following MALDI-MS analysis.
Karyotyping Mouse Cells
Authors: Nagy Andras , Gertsenstein Marina , Vintersten Kristina , Behringer Richard
Published: May 2008

INTRODUCTION

The majority of mouse chromosome preparations for banding are now made by air-drying and, in essence, require the production of a cell suspension as a starting point. Some samples such as blood cultures, ascitic fluids, or cells growing in suspension will already be in suspension; others, such as bone marrow, solid tumors, or cells growing as attached layers in culture must be converted to suspensions. The basic steps in karyotyping and banding embryonal carcinoma cells are outlined below.
Cutting Sections of Paraffin-Embedded Tissues
Authors: Fischer Andrew H. , Jacobson Kenneth A. , Rose Jack , Zeller Rolf
Published: May 2008

INTRODUCTION

This protocol describes the sectioning of tissues embedded in paraffin blocks. Paraffin sections require extensive fixation and processing steps but provide superior morphology compared with other sectioning methods. Sectioning paraffin blocks requires experience and should be learned from an experienced researcher, if possible.
Preparation of Slides and Coverslips for Microscopy
Authors: Fischer Andrew H. , Jacobson Kenneth A. , Rose Jack , Zeller Rolf
Published: May 2008

INTRODUCTION

It is imperative that the slides and coverslips used in fluorescence microscopy procedures be extremely clean. Although coverslips look clean, especially when a new box is first opened, they may have a thin film of grease on them that will not allow tissue culture cells to adhere well and that may interfere with some processing steps in certain protocols. Therefore, coverslips should routinely be washed with acid or base solutions to rid them of this film. Commercial precleaned slides are also likely to be dirty and must be washed prior to use. This protocol describes various approaches for cleaning slides and coverslips and sterilizing them for cell culture, as well as methods for subbing slides. In the subbing procedure, slides are coated with gelatin, aminoalkylsilane, or poly-L-lysine solution to promote the adhesion of cells or tissues to the glass surface. Gelatin or aminoalkylsilane is usually used for tissue sections or small organisms, whereas poly-L-lysine is routinely used for cultured cells.
Fixation and Permeabilization of Cells and Tissues
Authors: Fischer Andrew H. , Jacobson Kenneth A. , Rose Jack , Zeller Rolf
Published: May 2008

INTRODUCTION

Fluorescence microscopy is used to visualize specific cellular components in as native a state and organization as possible. This article describes some of the main issues that must be considered when cells and tissues are fixed and permeabilized. To preserve cellular structure, the specimen is fixed chemically to retain the cells or tissue in a state as near to life as possible by rapidly terminating all enzymatic and other metabolic activities to minimize post-fixation changes. Sample fixation is one of the most crucial steps in assuring the accuracy of detection protocols and is therefore decisive in determining the subsequent success or failure of a given experiment. Underfixation of the sample leads to poor morphological preservation and/or loss of signal, whereas overfixation may lead to fixation artifacts, loss of signal, and/or increased nonspecific background signals (“noise”). An ideal fixative should preserve a given antigen in a fashion that reflects the in vivo situation with respect to its distribution (no diffusion or rearrangement). Ideally, cell morphology should be preserved, the antigen of interest should remain accessible to the probe, and the fixation should cause minimal denaturation of the antigen. However, several of these goals are mutually incompatible, and therefore, a compromise must be attained.
Activated Expression of anArabidopsisHD-START Protein Confers Drought Tolerance with Improved Root System and Reduced Stomatal Density
Authors: Yu Hong , Chen Xi , Hong Yuan-Yuan , Wang Yao , Xu Ping , Ke Sheng-Dong , Liu Hai-Yan , Zhu Jian-Kang , Oliver David J. , Xiang Cheng-Bin
Published: May 2008

Drought is one of the most important environmental constraints limiting plant growth and agricultural productivity. To understand the underlying mechanism of drought tolerance and to identify genes for improving this important trait, we conducted a gain-of-function genetic screen for improved drought tolerance in Arabidopsis thaliana. One mutant with improved drought tolerance was isolated and designated as enhanced drought tolerance1. The mutant has a more extensive root system than the wild type, with deeper roots and more lateral roots, and shows a reduced leaf stomatal density. The mutant had higher levels of abscisic acid and Pro than the wild type and demonstrated an increased resistance to oxidative stress and high levels of superoxide dismutase. Molecular genetic analysis and recapitulation experiments showed that the enhanced drought tolerance is caused by the activated expression of a T-DNA tagged gene that encodes a putative homeodomain-START transcription factor. Moreover, overexpressing the cDNA of the transcription factor in transgenic tobacco also conferred drought tolerance associated with improved root architecture and reduced leaf stomatal density. Therefore, we have revealed functions of the homeodomain-START factor that were gained upon altering its expression pattern by activation tagging and provide a key regulator that may be used to improve drought tolerance in plants.
Future of Oil: Trends and Surprises
Authors: Smil Vaclav
Published: May 2008

Recent forecasts of an early decline in global oil extraction are just the latest additions to a long list of failed predictions. The timing of this event depends not only on the unknown quantity of ultimately recoverable crude oil resources, but also on the rates of demand growth, which are determined by a complex interplay of energy substitutions, technical advances, government policies and environmental considerations. Consequently, all past efforts to pinpoint the peak years of global oil output and its subsequent decline have been unsuccessful. And, even if the most pessimistic forecasts of an early end to the oil era were correct, we should not see the demise of today’s cheap oil as a cause of major economic and political difficulties. Historical perspectives show that transitions to new energy sources have been a critical factor in human evolution, driving our inventiveness and shaping our complex societies.
Changes to the Oil Export Structure of OPEC Member Countries — an Analysis with the Gini Coefficient
Authors: Dahmani Atmane
Published: May 2008

This paper’s goal is to analyse the impact of changes to the oil export structure on economic growth in OPEC Member Countries. The Gini coefficient has been applied simultaneously as a measure of the annual changes in the structure of per capita oil exports, as well as of the annual share of oil exports among Member Countries.

The analysis consists of a calculation of the concentration coefficients, a determination of their trend and an identification of the factors most influencing observed changes to the oil export structure in these countries.

As a result, we find that economic growth, crude oil production, proven reserves, imports and time are the major factors influencing changes to the oil export structure. Considering the changed structure, in the context of differences in oil export distribution, we observe that economic growth and production have a positive impact on the distribution of oil exports and that proven reserves and imports have a negative impact.
Priorities for Electric Energy Utilisation Research in the USA
Authors: Gellings Clark W.
Published: May 2008

Over the past 25 years, the role of electric power has grown steadily in both scope and importance. Developments in key technologies, such as electric lighting, motors, computers and telecommunications, have continuously reshaped American life and the productivity of its commercial and industrial foundation. As technology advances, electricity accounts for a progressively larger share of total energy consumption.

Even 25 years ago, the electric power industry acknowledged that research and development goals must relate to society’s ability to use electric energy to ascertain a better way of life and an enhanced environment. Included were specific goals in energy utilisation research.

Today the technology underpinning the electricity enterprise — from production to end‐use — is undergoing change at a pace and scope unmatched since the dawn of commercial electrification. The electric power industry’s structure, institutions and policies are now being transformed as well. Looking ahead, these technical and institutional transformations are expected to continually expand the value and role for electricity.

Today’s focus on research and development has widened and solidified and can now be categorised by two visions: (1) concerning electrification and economic growth, and (2) concerning electrification for the quality of life and national security.
Electricity Demand and Intensity: A Perspective on the Major Influencing Factors
Authors: Gürer Nadir , Ban Jan
Published: May 2008

Rapidly rising electricity demand in developing countries has greatly exceeded these countries’ pace of economic growth in recent years, as well as being double the rate of electricity demand growth in the OECD group and the world at large. Such dynamic growth in the electricity sector, which has been occurring in order to sustain the development process in developing countries, is now being constrained by substantial investment requirements and environmental challenges. This paper focuses on the factors influencing electricity demand. Within an empirical framework, the relationships between electricity demand and some major factors, such as GDP, prices and levels of urbanisation and industrialisation, are investigated for countries at different income levels. The calculations of intensities, income levels and prices, based on PPP‐adjusted rates, have resulted in the observation of lower intensities than otherwise would have been given, as well as a generally stronger dependence of electricity demand on price, GDP and the industrialisation level than anticipated.
Investigation of the porcine MUC13 gene: isolation, expression, polymorphisms and strong association with susceptibility to enterotoxigenic Escherichia coli F4ab/ac
Authors: Zhang B. , Ren J. , Yan X. , Huang X. , Ji H. , Peng Q. , Zhang Z. , Huang L.
Published: May 2008

Enterotoxigenic Escherichia coli (ETEC) F4ab and F4ac are major determinants of piglet diarrhoea. The locus for the ETEC F4ab/ac receptor has been mapped to SSC13q41. MUC13 is a transmembrane mucin expressed predominantly in the epithelial surface of the gastrointestinal tract and the MUC13 gene was assigned to SSC13q41, supporting it as a positional candidate gene for the ETEC F4ab/ac receptor. We herein determined the complete 2679‐bp cDNA of pig MUC13, and proved that it was most highly expressed in the jejunum and moderately expressed in the trachea, stomach and liver. Furthermore, 13 MUC13 polymorphisms were identified in 19 founder animals of a White Duroc × Erhualian resource population, and a total of 727 F2 animals with in vitro ETEC F4ab/ac adhesion phenotypes in this population were genotyped for three identified MUC13 polymorphisms including c.576C>T, c.908A>G and c.935A>C. The transmission disequilibrium test showed that the MUC13 alleles and haplotypes were significantly associated with susceptibility/resistance to ETEC F4ab/ac, especially between haplotype [C;G;A] and susceptibility to ETEC F4ac (P = 8.0e‐18). Animals inheriting this haplotype were predominantly susceptible to ETEC F4ac (n = 291/303). Moreover, nearly all animals homozygous for haplotype [T;G;C] (n = 39/41) and a majority of those with the [C;A;A]/[T;G;C] haplotype pair (n = 79/88) were resistant to ETEC F4ab. Our results indicated that MUC13 is in strong linkage disequilibrium with the ETEC F4ab/ac receptor locus and provided potential markers for selection of ETEC F4ab/ac‐resistant animals in the pig breeding scheme.
Discovery and evaluation of single nucleotide polymorphisms (SNPs) for Haliotis midae: a targeted EST approach
Authors: Bester A. E. , Roodt‐Wilding R. , Whitaker H. A.
Published: May 2008

In this study, we describe the first set of SNP markers for the South African abalone, Haliotis midae. A cDNA library was constructed from which ESTs were selected for the screening of SNPs. The observed frequency of SNPs in this species was estimated at one every 185 bp. When characterized in wild‐caught abalone, the minor allele frequencies and FST estimates for every SNP indicated that these markers may potentially be useful for population analysis, parentage assignment and linkage mapping in Haliotis midae. No linkage disequilibrium was observed between SNPs originating from different EST sequences. These SNPs, together with additional SNPs currently being developed, will provide a useful complementary set of markers to the currently available genetic markers in abalone.
RADIATION DEPIGMENTATION OF MOUSE HAIR: A STUDY OF FOLLICULAR MELANOCYTE POPULATIONS
Authors: Potten Christopher S.
Published: May 2008

The radiation depigmentation of mouse hair has been studied by a technique enabling melanocyte per follicle counts to be made. Distributions for normal skin show a large peak corresponding to the zigzag hair type. Changes in the frequency distributions of melanocytes per follicle after irradiation are presented for Strong F and DBA‐1 mice irradiated in anagen or telogen stages of hair growth. These distributions clearly suggest the existence of some precursor cells, and the dose‐response curves obtained by defining radiation survivors as follicles containing more than ten melanocytes gives the sensitivity of these cells to inactivation. D0 values are 180–220 rads. A melanocyte‐melanoblast model is proposed for the follicular melanocyte cycle which can be outlined as follows: The telogen follicle contains a small number of amelanotic melanocytes that survived through catagen. These cells possess the ability to repopulate the follicle with melanocytes. In catagen functional and/or amelanotic melanocytes are lost at random. Genes for dilution (possibly only when modified by other coat colour genes) and radiation both increase the chance of melanocyte loss at catagen by altering the melanocyte‐dermal papilla relationship. One way in which this is affected is by a shortening of the dendrites. A feedback may operate in the follicle so that the full complement of melanocytes is achieved whatever number of melanocytes persists in telogen.
THE EFFECTS OF CYTOSINE ARABINOSIDE ON THE CELL CYCLE OF CULTURED HUMAN LEUCOCYTES: A MICRODENSITOMETRIC AND AUTORADIOGRAPHIC STUDY
Authors: Brehaut Loreen A. , Fitzgerald P. H.
Published: May 2008

PHA‐stimulated leucocytes treated with cytosine arabinoside showed a changed uptake of [3H]thymidine, a lowered mitotic index and chromosome damage. Combined autoradiography and Feulgen microdensitometry demonstrated inhibition of DNA synthesis. Cells in the S period of the cell cycle were arrested in their progress, and cells newly entering S accumulated at the beginning of this period. At stronger concentrations these effects on the cell cycle were complicated by the cytotoxic effect of cytosine arabinoside.

The inhibition of DNA synthesis is considered in the light of the chromosomal damage and megaloblastic changes caused by cytosine arabinoside, and is compared to the different pattern of DNA arrest found in megaloblastic anaemia.
CLONE SIZE ANALYSIS: A PARAMETER IN THE STUDY OF CELL POPULATION KINETICS
Authors: Nias A. H. W.
Published: May 2008

The method of clone size analysis is described. Such an analysis provides a measure of the distribution of generation times in a cell population. Treatment by ionizing irradiation leads to perturbation of the generation times of a cell population and such perturbations are shown by changes in the clone size distribution. Distributions were compared after neutron irradiation and β‐irradiation with those after X‐rays; and also between X‐irradiation under aerobic and anoxic conditions. At the same level of cell survival no differences were found between the patterns of cell survival with respect to generation times. Other uses of clone size analysis are discussed.
CONTROL OF GRANULOCYTE PRODUCTION
Authors: Rytömaa T. , Kiviniemi Kyllikki
Published: May 2008

In normal conditions the granulocytic cell population is prevented from excessive cell proliferation by a humoral mechanism based on a specific feedback inhibitor, granulocytic chalone. In conditions of acute functional demand a tissue‐specific stimulator, granulocytic antichalone, replaces chalone in rat serum.

Mature granulocytes contain, and presumably produce, the chalone which is also present in fresh normal serum. Thus, the inhibitor is both humoral and present within the same cell system on which it acts: the action of this chalone is target tissue specific as it only inhibits granulocytic precursor cells in normal rat bone marrow in vitro.

Granulocytic chalone and antichalone were partly purified by gel filtration on Sephadex; the elution parameters suggested molecular weights of 4000 and 30,000–35,000, respectively. Granulocytic chalone was not separated from the erythrocytic chalone (present in fresh normal serum and in blood erythrocytes) on Sephadex; however, separation at the cellular level was easily achieved.
KINETICS OF CELL RENEWAL, CELL MIGRATION AND CELL LOSS IN THE HAIRLESS MOUSE DORSAL EPIDERMIS
Authors: Iversen Olav Hilmar , Bjerknes Rolf , Devik Finn
Published: May 2008

Forty hairless mice were given injections of tritiated thymidine every 4th hour during 10 days. At 24 hr intervals groups of four mice were killed. The numbers of labelled basal and differentiating cells were determined by autoradiography with a stripping film technique. To determine the background activity skin sections from uninjected control mice were subjected to the same stripping film procedure.

Another group of hairless mice was given one single pulse labelling with tritiated thymidine. The number of labelled mitoses was scored for 12 hr after the injection. At 10, 12 and 15 hr after the injection, the numbers of labelled basal and differentiating cells were also determined.

A mathematical model of cell population kinetics in the epidermis has been suggested. The results of different simulations on this model were compared with the observed results.

The curve of mean grain counts under continuous labelling increased from day to day with two well‐defined plateaux.

The percentage of all labelled cells increased rapidly up to the 3rd day, and thereafter the curves gradually flattened off. When basal cells and differentiated cells were considered separately the labelling index of the basal cells increased rapidly for the first 3 days and then flattened off at the 100% level on the 5th day.

The labelling index of the differentiating cells was low during the first 3–4 days. Then a steep increase in the percentage of labelled differentiating cells was seen, but the curve flattened off again close to the 100 % level after the 7th day. The labelled mitosis curve had its maximum 5 hr after the thymidine injection. The curve fell again to almost zero at 12 hr. Ten, 12 and 15 hr after the injection, 6, 7 and 7% respectively of the labelled cells were found in the spinous layer.

It was concluded that three grains over each nucleus could be used as lower limit for considering a cell as labelled. On this basis, tritiated thymidine injections every 4th hour can be considered as continuous labelling.
STUDIES ON LYMPHOCYTES
Authors: Vincent P. C. , Borner G. , Chanana A. D. , Cronkite E. P. , Greenberg M. L. , Joel D. D. , Schiffer L. M. , Stryckmans P. A.
Published: May 2008

Some of the time parameters of the cell cycle in bovine thoracic duct lymphocytes have been estimated by analysing labeled mitoses curves, and by double labeling.

The two methods gave similar estimates of Ts. Thus, Ts measured directly from labeled mitoses curves varied from 4 to 6 hr, while the estimates from double labeling were 4.8 and 4.5 hr.

T
G measured directly from labeled mitoses curves was 5 hr, and estimates of TG from the values of Ts ranged from 6.3 to 7.7 hr.

The present data confirm the short generative cycle of large thoracic duct lymphocytes.

Extracorporeal irradiation of the lymph (ECIL) had no detectable effect on the cell cycle or the fractional production rate of the lymphocytes. However, the calculated absolute production was reduced following ECIL, due to a decrease in the absolute number of cells present.

The grain count over mitoses after ECIL was approximately one‐half that found before ECIL.
INDUCTION OF CELL PROLIFERATION IN THE MOUSE BLADDER BY 4‐ETHYLSULPHONYL‐NAPHTHALENE‐1 ‐SULPHONAMIDE
Authors: Levi Patricia E. , Cowen Diana M. , Cooper E. H.
Published: May 2008

The reaction of the bladder epithelium of mice, following stimulation with a carcinogen, 4‐ethylsulphonylnaphthalene‐1‐sulphonamide (ENS), was studied. A wave of cell division was induced in the resting epithelium, diploid and tetraploid cells being the main dividing elements; some of the high ploidy surface cells also underwent division. The cell cycle time for the diploid and tetraploid cells appeared to be identical. There was considerable variation in the intensity and timing of the onset of cell division in the bladder epithelium of individual animals. ENS caused severe damage to the surface cells of the bladder epithelium as indicated by increased lysosomes and the formation of large vacuoles.
THE ROLE OF STRESS HORMONES IN THE CONTROL OF GRANULOCYTE PRODUCTION
Authors: Rytömaa T. , Kiviniemi Kyllikki
Published: May 2008

It has previously been indicated that the inhibitory power of the granulocytic chalone is not influenced by adrenalin. It is now shown that this is true both in absence and in presence of exogenous hydrocortisone.

It is also shown that hydrocortisone itself does not cause significant inhibition of DNA synthesis in rat bone marrow cells in vitro, but that it does act to augment the inhibitory effect which the granulocytic chalone induces.

It is suggested that the primary action of hydrocortisone may be on the cell membrane which changes the cell wall permeability to chalone, perhaps by reducing its rate of loss from the cells.