bluuebunny/crossref_metadata_2025 huggingface dataset:
Sub-ms laser pulse irradiation on tungsten target damaged by exposure to helium plasma
Authors: Kajita Shin , Takamura Shuichi , Ohno Noriyasu , Nishijima Dai , Iwakiri Hirotomo , Yoshida Naoaki
Published: September 2007

The effects of a transient heat load on tungsten damaged by helium plasma irradiation have been investigated using a ruby laser with long pulse duration in the divertor simulator NAGDIS-II (Takamuraet al2002Plasma Sources Sci. Technol.11A42). The pulse width of the ruby laser was ∼0.6 ms, which is close to that of the expected heat load accompanied by type-I edge localized modes (ELMs) in ITER operation. Helium holes/bubbles, which were formed in the surface region of powder metallurgy tungsten due to the exposure to the helium plasma, disappeared after the laser pulse irradiation to the tungsten surface with sufficient pulse energy. The results indicated that the transient heat loads similar to those expected by ELMs will mitigate damages such as bubbles and holes produced by helium irradiation. When a vacuum plasma sprayed tungsten coating on graphite was exposed to the helium plasma, the surface was covered with arborescent nanostructured tungsten containing many helium bubbles inside the structure. Melting traces were found on the surface after the laser pulses irradiated the surface even though the pulse energy was lower than that for melting bulk tungsten. A numerical temperature calculation of the sample suggested that the effective thermal conductivity near the surface dramatically decreased by several orders of magnitude due to the formation of nanostructured tungsten.
Experimental electron heat diffusion in ECH plasmas of the TJ-II stellarator
Authors: Vargas V.I. , López-Bruna D. , Herranz J. , Castejón F.
Published: September 2007

Interpretative transport has been used to revisit the global scalings of TJ-II plasmas with electron cyclotron resonance heating (ECH), from a local perspective. Density, rotational transform and ECH power scans were analysed based mainly upon Thomson scattering data (electron density and temperature) in steady state discharges. The thermal diffusivity χeis estimated assuming pure diffusion and negligible convective heat fluxes in a set of 201 discharges. The density scan indicates that for normalized minor radii ρ ≲ 0.4 there is no significant change of χewith density in the range studied, while in the density gradient region, χedecreases with line density. In the rotational transform scan, there is an overall tendency of χeto decrease with increasing rotational transform, but we also find that the presence of a low order rational value of the rotational transform is accompanied by a localloweringof χe. Finally, in the ECH power scan, χeis found to have an overall increment in 0.2 < ρ < 0.6 whenQECHincreases from 200 to 400 kW, although it is less significant in the density gradient region.
Progress towards steady state at low aspect ratio on the National Spherical Torus Experiment (NSTX)
Authors: Gates D.A. , Menard J. , Maingi R. , Kaye S. , Sabbagh S.A. , Diem S. , Wilson J.R. , Bell M.G. , Bell R.E. , Ferron J. , Fredrickson E.D. , Kessel C.E. , LeBlanc B.P. , Levinton F. , Manickam J. , Mueller D. , Raman R. , Stevenson T. , Stutman D. , Taylor G. , Tritz K. , Yu H.
Published: September 2007

Modifications to the plasma control capabilities and poloidal field coils of the National Spherical Torus Experiment (NSTX) have enabled a significant enhancement in shaping capability which has led to the transient achievement of a record shape factor (S≡q95(Ip/aBt)) of ∼41 (MA m−1 T−1) simultaneous with a record plasma elongation of κ ≡b/a∼ 3. This result was obtained using isoflux control and real-time equilibrium reconstruction. Achieving high shape factor together with tolerable divertor loading is an important result for future ST burning plasma experiments as exemplified by studies for future ST reactor concepts, as well as neutron producing devices, which rely on achieving high shape factors in order to achieve steady state operation while maintaining MHD stability. Statistical evidence is presented which demonstrates the expected correlation between increased shaping and improved plasma performance. Plasmas with high shape factor have been sustained for pulse lengths which correspond to τpulse= 1.6s∼ 50 τE∼ 5 τCR, where τCRis the current relaxation time and τEis the energy confinement time. Plasmas with higher βt∼ 20% have been sustained for τpulse= 1.2s∼ 25 τE∼ 3 τCRwith non-inductive current fractionsfNI∼ 50%, with ∼40% pressure driven current and ∼10% neutral beam driven current. An interesting feature of these discharges is the observation that the central value of the safety factorq(0) remains elevated and constant for several current diffusion times without sawteeth, similar to the ‘hybrid mode’. Calculations of the profiles of inductive and non-inductive current are compared with measurements of the total current profile and are shown to be in quantitative agreement. Results are shown from experiments which investigate the applicability of high harmonic fast waves (HHFWs) and electron Bernstein waves (EBWs) as current drive and heating sources, and the possibility of LHCD for future ST devices is raised. A calculated scenario which provides 100% non-inductive current drive is described. NSTX operates with peak divertor heat fluxes which are in the same range as those expected for the ITER device, i.e. with. High triangularity, high elongation plasmas on NSTX have been demonstrated to have reduced peak heat flux to the divertor plates to <3 MW m−2.
Main safety issues at the transition from ITER to fusion power plants
Authors: Gulden W. , Ciattaglia S. , Massaut V. , Sardain P.
Published: September 2007

In parallel to the ITER design process and in close cooperation with the designers a fusion-specific safety approach was developed and implemented. Detailed safety assessments have been performed and documented in the ITER Generic Site Safety Report (GSSR). Following the decision on ITER construction in France, results from the GSSR and from on-going safety-related activities tailored to the Cadarache site and the French licensing process are now being used to write the ITER Preliminary Safety Analysis Report.

In the most recent European fusion power plant conceptual study (PPCS) inherent fusion favourable features have been exploited, by appropriate design and choice of materials, to provide major safety and environmental advantages. The study focused on five power plant models, which are illustrative of a wider spectrum of possibilities. These span a range from relatively near-term concepts, based on limited technology and plasma physics extrapolations, to a more advanced conception. All five PPCS plant models differ substantially in their plasma physics, blanket and divertor technology, size, fusion power and materials compositions, and these differences lead to differences in economic performance and in the details of safety and environmental impacts.

This paper uses the quite detailed information available from ITER safety documents and highlights the differences between ITER and future fusion power plants. The main areas investigated are releases and doses during normal operation and under accidental conditions, occupational radiation exposure and optimization and waste management, including recycling and/or final disposal in repositories.

Due to an error, an incorrect version of this paper was published in issue 7. For the convenience of the reader we have included the correct full article below rather than a list of changes.
Characteristics of French Bread Baked from Wheat Flours of Reduced Starch Amylose Content
Authors: Park C. S. , Baik B.‐K.
Published: September 2007

Wheat genotypes of wild type, partial waxy, and waxy starch were used to determine the influence of starch amylose content on French bread making quality of wheat flour. Starch amylose content and protein content of flours were 25.0–25.4% and 14.3–16.9% for wild type; 21.2 and 14.9% for single null partial waxy; 15.4–17.1% and 13.2–17.6% for double null partial waxy; and 1.8 and 19.3% for waxy starch, respectively. Wheat flours of double null partial waxy starch produced smaller or comparable loaf volume of bread than wheat flours of wild type and single null partial waxy starch. Waxy wheat flour, despite its high protein content, generally produced smaller volume of bread with highly porous, glutinous, and weak crumb than wheat flours of wild type and partial waxy starch. French bread baked from a flour of double null partial waxy starch using the sponge‐and‐dough method maintained greater crumb moisture content for 24 hr and softer crumb texture for 48 hr of storage compared with bread baked from a flour of wild type starch. In French bread baked using the straight‐dough method, double null partial waxy wheat flours with protein content >14.3% exhibited comparable or greater moisture content of bread crumb during 48 hr of storage than wheat flours of wild type starch. While the crumb firmness of bread stored for 48 hr was >11.4 N in wheat flours of wild type starch, it was <10.6 N in single or double null partial waxy flours. Wheat flours of reduced starch amylose content could be desirable for production of French bread with better retained crumb moisture and softness during storage.
Developing sustainable food supply chains
Authors: Smith B. Gail
Published: September 2007

This paper reviews the opportunities available for food businesses to encourage consumers to eat healthier and more nutritious diets, to invest in more sustainable manufacturing and distribution systems and to develop procurement systems based on more sustainable forms of agriculture. The important factors in developing more sustainable supply chains are identified as the type of supply chain involved and the individual business attitude to extending responsibility for product quality into social and environmental performance within their own supply chains. Interpersonal trust and working to standards are both important to build more sustainable local and many conserved food supply chains, but inadequate to transform mainstream agriculture and raw material supplies to the manufactured and commodity food markets. Cooperation among food manufacturers, retailers, NGOs, governmental and farmers’ organizations is vital in order to raise standards for some supply chains and to enable farmers to adopt more sustainable agricultural practices.
Tension-sensitive Plk1 phosphorylation on BubR1 regulates the stability of kinetochore–microtubule interactions
Authors: Elowe Sabine , Hümmer Stefan , Uldschmid Andreas , Li Xiuling , Nigg Erich A.
Published: September 2007

Mitotic phosphorylation of the spindle checkpoint component BubR1 is highly conserved throughout evolution. Here, we demonstrate that BubR1 is phosphorylated on the Cdk1 site T620, which triggers the recruitment of Plk1 and phosphorylation of BubR1 by Plk1 both in vitro and in vivo. Phosphorylation does not appear to be required for spindle checkpoint function but instead is important for the stability of kinetochore–microtubule (KT–MT) interactions, timely mitotic progression, and chromosome alignment onto the metaphase plate. By quantitative mass spectrometry, we identify S676 as a Plk1-specific phosphorylation site on BubR1. Furthermore, using a phospho-specific antibody, we show that this site is phosphorylated during prometaphase, but dephosphorylated at metaphase upon establishment of tension between sister chromatids. These findings describe the first in vivo verified phosphorylation site for human BubR1, identify Plk1 as the kinase responsible for causing the characteristic mitotic BubR1 upshift, and attribute a KT-specific function to the hyperphosphorylated form of BubR1 in the stabilization of KT–MT interactions.
ASY1 mediates AtDMC1-dependent interhomolog recombination during meiosis in Arabidopsis
Authors: Sanchez-Moran Eugenio , Santos Juan-Luis , Jones Gareth H. , Franklin F. Christopher H.
Published: September 2007

ASY1 is an Arabidopsis protein required for synapsis and crossover formation during meiosis. The chronology of meiotic recombination has been investigated in wild type and an asy1 mutant. We observe a delay between the appearance of chromatin-associated AtSPO11-1 foci and DNA double-strand break (DSB) formation, which occurs contemporaneously with chromosome axis formation and transition of ASY1 from chromatin-associated foci to a linear axis-associated signal. DSBs are formed independently of ASY1 in an AtSPO11-1-dependent manner. They are partially restored in Atspo11-1-3 using cisplatin, but their control appears abnormal. Axis morphogenesis is independent of ASY1, but axis structure may be compromised in asy1. Localization of the strand exchange proteins AtRAD51 and AtDMC1 to the chromatin occurs asynchronously shortly after DSB formation, with AtDMC1 localizing in advance of AtRAD51. In wild-type nuclei, both recombinases form numerous foci that persist for ∼12 h before gradually decreasing in number. In asy1, initial localization of AtDMC1 is normal, but declines abruptly such that interhomolog recombination is severely compromised. Limited ASY1-independent, DMC1-dependent interhomolog recombination remains, but appears restricted to subtelomeric sequences where the homologs are fortuitously in proximity. Thus, ASY1 plays a key role in coordinating the activity of the RecA homologs to create a bias in favor of interhomolog recombination.
Arabidopsis JACKDAW and MAGPIE zinc finger proteins delimit asymmetric cell division and stabilize tissue boundaries by restricting SHORT-ROOT action
Authors: Welch David , Hassan Hala , Blilou Ikram , Immink Richard , Heidstra Renze , Scheres Ben
Published: September 2007

In the Arabidopsis root, the SHORT-ROOT transcription factor moves outward to the ground tissue from its site of transcription in the stele and is required for the specification of the endodermis and the stem cell organizing quiescent center cells. In addition, SHORT-ROOT and the downstream transcription factor SCARECROW control an oriented cell division in ground tissue stem cell daughters. Here, we show that the JACKDAW and MAGPIE genes, which encode members of a plant-specific family of zinc finger proteins, act in a SHR-dependent feed-forward loop to regulate the range of action of SHORT-ROOT and SCARECROW. JACKDAW expression is initiated independent of SHORT-ROOT and regulates the SCARECROW expression domain outside the stele, while MAGPIE expression depends on SHORT-ROOT and SCARECROW. We provide evidence that JACKDAW and MAGPIE regulate tissue boundaries and asymmetric cell division and can control SHORT-ROOT and SCARECROW activity in a transcriptional and protein interaction network.
Functional conservation of Rel binding sites in drosophilid genomes
Authors: Copley Richard R. , Totrov Maxim , Linnell Jane , Field Simon , Ragoussis Jiannis , Udalova Irina A.
Published: September 2007

Evolutionary constraints on gene regulatory elements are poorly understood: Little is known about how the strength of transcription factor binding correlates with DNA sequence conservation, and whether transcription factor binding sites can evolve rapidly while retaining their function. Here we use the model of the NFKB/Rel-dependent gene regulation in divergent Drosophila species to examine the hypothesis that the functional properties of authentic transcription factor binding sites are under stronger evolutionary constraints than the genomic background. Using molecular modeling we compare tertiary structures of the Drosophila Rel family proteins Dorsal, Dif, and Relish and demonstrate that their DNA-binding and protein dimerization domains undergo distinct rates of evolution. The accumulated amino acid changes, however, are unlikely to affect DNA sequence recognition and affinity. We employ our recently developed microarray-based experimental platform and principal coordinates statistical analysis to quantitatively and systematically profile DNA binding affinities of three Drosophila Rel proteins to 10,368 variants of the NFKB recognition sequences. We then correlate the evolutionary divergence of gene regulatory regions with differences in DNA binding affinities. Genome-wide analyses reveal a significant increase in the number of conserved Rel binding sites in promoters of developmental and immune genes. Significantly, the affinity of Rel proteins to these sites was higher than to less conserved sites and was maintained by the conservation of the DNA binding site sequence (static conservation) or in some cases despite significantly diverged sequences (dynamic conservation). We discuss how two types of conservation may contribute to the stabilization and optimization of a functional gene regulatory code in evolution.
Histidine Phosphorylation Site Identification by ESI-MS: Figure 1.
Authors: Sickmann Albert , Meyer Helmut E.
Published: September 2007

INTRODUCTION

Histidine phosphate is moderately stable under alkaline conditions; however, the half-life of this phosphoamino acid under acidic conditions (pH <5) is less than 20 min. Thus, it is better to process proteins containing phosphohistidine rapidly and under alkaline conditions. The use of acidic matrices such as α-cyano-4-hydroxycinnamic acid for MALDI-MS prevents the detection of phosphohistidine. An alkaline MALDI matrix is a poor alternative because it often decreases the sensitivity of detection of phosphorylated amino acids. Surprisingly, phosphohistidine is stable under acidic conditions when stored on C18 column resins. Therefore, HPLC separation on C18 resin with an acidic solvent system combined with ESI-MS is possible.
Observational Methods Used to Assess Rat Behavior: Behavioral Patterns
Authors: Paul Carol Ann , Beltz Barbara , Berger-Sweeney Joanne
Published: September 2007

INTRODUCTION

This protocol describes a method for quantifying observation of normal rat behaviors in a controlled environment and in a defined area. It is necessary to have precise definitions of the behaviors to be quantified and a reliable procedure for quantifying them. The observation room should be quiet, and it should be equipped for light or dark observations (rats cannot see red light so dark observations can be made using a red light). Ideally, the observer should be separated from the animal by a one-way screen. If such a screen is not available, the observer should stand or sit in a constant, unobtrusive position and make as few movements as possible.
Drosophila Embryo Dechorionation
Authors: Rothwell Wendy F. , Sullivan William
Published: September 2007

INTRODUCTION

Early Drosophila embryos are particularly amenable to cellular analysis. However, they are protected by an outer chorion layer, as well as an impermeable and opaque vitelline membrane. Consequently, preparation of Drosophila embryos for fixed-sample analysis must include procedures for chorion removal, vitelline membrane permeabilization, fixation, and finally, vitelline membrane removal. This protocol describes a method for removing the chorion layer.
Fixation of Drosophila Embryos
Authors: Rothwell Wendy F. , Sullivan William
Published: September 2007

INTRODUCTION

A number of techniques are available for fixation of Drosophila embryos, each with their own advantages and limitations. The technique appropriate for a specific study will depend on a number of variables, including the preservation qualities of the cellular components to be examined, the position of the components within the embryos, and the probe used. Formaldehyde-based techniques are useful for preserving deep and/or cytoskeletal elements. Fixation with methanol or boiling is harsher, but both result in nearly total devitellinization of the embryos. Fixation without methanol requires devitellinization of the embryos by hand. While the most tedious, this latter method often produces the highest-quality results. It may be necessary to try all of these techniques to determine which one is the most appropriate for each new antibody or reagent.
Cutaneous Two-Stage Chemical Carcinogenesis
Authors: Filler Renata B. , Roberts Scott J. , Girardi Michael
Published: September 2007

INTRODUCTION

The induction of cutaneous carcinogenesis in mice by topical administration of chemicals enables the local, systemic, and environmental factors that influence tumor susceptibility, growth, and progression to be studied in the laboratory. Chemical carcinogenesis in mouse skin has been used for several decades, and continues to help in the identification of important molecular and immunological pathways involved in cutaneous malignancy. This protocol describes the two-stage application of chemicals to the skin for the initiation and promotion of cutaneous tumors. In the two-stage model of induction, a single application of the chemical initiator mutagen 7,12-dimethylbenz[a]anthracene (DMBA) is followed by repeated applications of a pro-inflammatory phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA; otherwise known as phorbol 12-myristate 13-acetate [PMA]). Resulting tumors may develop in the form of benign papillomas that regress or progress to SCC, or SCC may arise without an apparent precursor lesion. Thus, two-stage chemical carcinogenesis provides an opportunity to monitor early and late events in cancer development and progression.
Generation of Transgenic Xenopus laevis: III. Sperm Nuclear Transplantation
Authors: Ishibashi Shoko , Kroll Kristin L. , Amaya Enrique
Published: September 2007

INTRODUCTION

Manipulating genes specifically during later stages of amphibian embryonic development requires fine control over the time and place of expression. These protocols describe an efficient nuclear-transplantation-based method of transgenesis developed for Xenopus laevis. The approach enables stable expression of cloned gene products in Xenopus embryos. The procedure is based on restriction-enzyme-mediated integration (REMI) and can be divided into three parts: (I) high-speed preparation of egg extracts, (II) sperm nuclei preparation, and (III) nuclear transplantation. This protocol describes a method for the nuclear transplantation in Xenopus laevis. Permeabilized sperm nuclei are incubated briefly with linearized plasmid DNA, after which egg extract and a small amount of restriction enzyme are added. The egg extract partially decondenses the chromosomes, and the restriction enzyme stimulates recombination by creating double-strand breaks, facilitating integration of DNA into the genome. Diluted nuclei are transplanted into unfertilized eggs. Because the transgene integrates into the genome prior to fertilization, the resulting transgenic embryos are not chimeric and there is no need to breed to the next generation in order to obtain nonmosaic transgenic animals.
Persistence of Treatment and Blood Pressure Control in Elderly Hypertensive Patients Treated With Different Classes of Antihypertensive Drugs
Authors: Borghi Claudio , Veronesi Maddalena , Dormi Ada , Prandin Maria Grazia , Cosentino Eugenio , Strocchi Enrico
Published: September 2007

Unsatisfactory blood pressure (BP) control in the treated hypertensive patient is largely related to poor compliance with antihypertensive drug regimens. The aim of the present study was to prospectively evaluate the rate of persistence on treatment and the extent of BP control in 301 elderly, uncomplicated grade I or II hypertensive patients randomly allocated to monotherapy with angiotensin‐converting enzyme (ACE) inhibitors, calcium channel blockers (CCBs), β‐blockers, angiotensin II receptors (ARBs), or diuretics according to an open‐label single‐blind study design. After 24 months, the percentage of patients continuing their initial therapy was higher in those treated with ARBs (68.5%) and ACE inhibitors (64.5%) and lower in patients taking diuretics (34.4%; P<.01). The logistic regression model using ARBs as reference term showed that patients treated with ACE inhibitors (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.79–0.99) or CCBs (OR, 0.76; 95% CI, 0.54–0.85) were more likely to continue their initial antihypertensive therapy when compared with those treated with β‐blockers (OR, 0.67; 95% CI, 0.57–0.79) or diuretics (OR, 0.56; 95% CI, 0.38–0.84). The average systolic and diastolic BP decrease was greater in patients treated with ARBs (−11.2±4/−5.8±2 mm Hg), ACE inhibitors (−10.5±4/−5.1±2 mm Hg), and CCBs (−8.5±3/−4.6±2 mm Hg) and lesser in those treated with diuretics (−2.3±4/−2.1±3 mm Hg, P<.05) and β‐blockers (−4.0±2/−2.3±2 mm Hg; P<.05). The study confirms the importance of persistence with treatment for the effective management of hypertension in clinical practice.
Acute phase proteins do not account for unmeasured anions in critical illness
Authors: Kneidinger N. , Lindner G. , Fuhrmann V. , Doberer D. , Dunkler D. , Schneeweiss B. , Funk G. C.
Published: September 2007

Background  The increasingly recognized prognostic impact of the strong ion gap in critical illness is in contrast to its largely unknown chemical nature. Experimental and clinical evidence suggest that acute phase proteins might account for elevation of the strong ion gap. The hypothesis of this investigation was that acute phase proteins account for strong ion gap in critically ill patients.

Materials and methods  The charges of the two acute phase proteins C‐reactive protein and fibrinogen were estimated by a computer model. Additionally, 142 patients admitted to a medical intensive care unit of a university hospital were studied prospectively during a six month period. Serial daily observations were recorded and classified according to the systemic inflammatory state. The acute phase proteins C‐reactive protein and fibrinogen were measured and the strong ion gap was calculated from the measured acid‐base variables.

Results  The approximated mean charges of C‐reactive protein and fibrinogen at a pH of 7·4 are –4·0 and –13·6 per molecule, respectively. Therefore, their negative charge is too small to explain the elevated strong ion gap even during a substantial increase of C‐reactive protein and fibrinogen due to an acute‐phase reaction. Moreover, C‐reactive protein did not correlate with the strong ion gap when partialized for creatinine (R = 0·02, P = 0·567). Fibrinogen did not correlate with the strong ion gap. Creatinine correlated with the strong ion gap (R = 0·42, P < 0·001). Neither systemic inflammatory state nor increasing C‐reactive protein levels were associated with an increasing strong ion gap.

Conclusion  Acute phase proteins do not account for an elevated strong ion gap in critically ill patients.
Arteriogenesis: basic mechanisms and therapeutic stimulation
Authors: Grundmann S. , Piek J. J. , Pasterkamp G. , Hoefer I. E.
Published: September 2007

Pharmacological attempts to stimulate the growth of collateral arteries (arteriogenesis) are evolving towards a new treatment option for patients with vascular occlusive diseases. This enlargement of small pre‐existing anastomoses towards large conductance arteries takes place independent of local oxygen tension and is driven by changes in luminal shear stress and infiltration of circulating cells. With the increasing knowledge regarding the distinct differences between capillary sprouting (angiogenesis) and arteriogenesis, several cytokines and growth factors have been demonstrated to stimulate the growth of arterial blood vessels in preclinical models of vascular disease. However, the translation towards clinical practice remains difficult and first in‐man trials show limited success. Intensive research especially regarding new drug delivery platforms and the potentially serious side effects of pro‐arteriogenic therapeutics is warranted before stimulation of arteriogenesis could become a significant treatment option for vascular occlusive diseases. This review focuses on the recent advances in the field of collateral artery growth. In addition, possible means to overcome the hurdles that have hampered the clinical implementation of pro‐arteriogenic therapies will be discussed.
Patterns of relatedness and parentage in an asocial, polyandrous striped hyena population
Authors: WAGNER AARON P. , CREEL SCOTT , FRANK LAURENCE G. , KALINOWSKI STEVEN T.
Published: September 2007

We investigated patterns of relatedness and reproduction in a population of striped hyenas in which individuals are behaviourally solitary but form polyandrous spatial groups consisting of one adult female and multiple adult males. Group‐mate males were often close relatives, but were unrelated or distantly related in some cases, indicating that male coalitions are not strictly a result of philopatry or dispersal with cohorts of relatives. Most male–female pairs within spatial groups were unrelated or only distantly related. Considering patterns of relatedness between groups, relatedness was significantlyhigheramong adult males living in non‐neighbouring ranges than among neighbouring males. Mean relatedness among male–female dyads was highest for group‐mates, but relatedness among non‐neighbouring males and females was also significantly higher than among dyads of opposite‐sex neighbours. Female–female relatedness also increased significantly with increasing geographic separation. These unusual and unexpected patterns may reflect selection to settle in a nonadjacent manner to reduce inbreeding and/or competition among relatives for resources (both sexes), or mates (males). Finally, resident males fathered the majority of the resident female's cubs, but extra‐group paternity was likely in 31% of the cases examined, and multiple paternity was likely in half of the sampled litters.
Behavioural inbreeding avoidance in wild African elephants
Authors: ARCHIE ELIZABETH A. , HOLLISTER‐SMITH JULIE A. , POOLE JOYCE H. , LEE PHYLLIS C. , MOSS CYNTHIA J. , MALDONADO JÉSUS E. , FLEISCHER ROBERT C. , ALBERTS SUSAN C.
Published: September 2007

The costs of inbreeding depression, as well as the opportunity costs of inbreeding avoidance, determine whether and which mechanisms of inbreeding avoidance evolve. In African elephants, sex‐biased dispersal does not lead to the complete separation of male and female relatives, and so individuals may experience selection to recognize kin and avoid inbreeding. However, because estrous females are rare and male–male competition for mates is intense, the opportunity costs of inbreeding avoidance may be high, particularly for males. Here we combine 28 years of behavioural and demographic data on wild elephants with genotypes from 545 adult females, adult males, and calves in Amboseli National Park, Kenya, to test the hypothesis that elephants engage in sexual behaviour and reproduction with relatives less often than expected by chance. We found support for this hypothesis: males engaged in proportionally fewer sexual behaviours and sired proportionally fewer offspring with females that were natal family members or close genetic relatives (both maternal and paternal) than they did with nonkin. We discuss the relevance of these results for understanding the evolution of inbreeding avoidance and for elephant conservation.
High prevalence of multiple paternity within fruits in natural populations of Silene latifolia, as revealed by microsatellite DNA analysis
Authors: TEIXEIRA SARA , BERNASCONI GIORGINA
Published: September 2007

Data on multiple paternity within broods has been gathered in several animal species, and comparable data in plants would be of great importance to understand the evolution of reproductive traits in a common framework. In this study, we first isolated and characterized six microsatellite loci from the dioecious plant Silene latifolia (Caryophyllaceae). The polymorphism of the loci was assessed in 60 individual females from four different populations. Two of the investigated loci showed a pattern of inheritance consistent with X‐linkage. These microsatellite loci were highly polymorphic and therefore useful tools for parentage analysis. We then used four of the markers to determine paternity within naturally pollinated fruits in four European populations. This study revealed widespread multiple paternity in all populations investigated. The minimum number of fathers per fruit varied from one to nine, with population means ranging from 3.4 to 4.9. The number of fathers per fruit was not significantly correlated with offspring sex ratios. High prevalence of multiple paternity within fruits strongly suggest that pollen competition is likely to occur in this species. This may substantially impact male reproductive success and possibly contribute to increase female and offspring fitness, either through postpollination selection or increased genetic diversity. Wide variation in outcrossing rates may be an overlooked aspect of plant mating systems.
Menstrual versus clinical estimate of gestational age dating in the United States: temporal trends and variability in indices of perinatal outcomes
Authors: Ananth Cande V.
Published: September 2007

Accurate estimation of gestational age early in pregnancy is paramount for obstetric care decisions and for determining fetal growth and other conditions that may necessitate timing the iatrogenic intervention or delivery. We sought to examine temporal changes in the distributions of two measures of gestational age, namely, those based on menstrual dating and a clinical estimate. We further sought to evaluate relative comparisons and variability in indices of perinatal outcomes. We utilised the Natality data files in the US, 1990–2002 comprising women that delivered a singleton livebirth between 22 and 44 weeks gestation (n = 42 689 603).

Changes were shown in the distributions of gestational age based on menstrual vs. clinical estimate between 1990 and 2002, as well as changes in the proportions of preterm (<37, <32 and <28 weeks) and post‐term (≥42 weeks) birth, and small‐ (SGA; <10th percentile) and large‐for‐gestational‐age (LGA; birthweight >90th percentile) births. While the absolute rates of preterm birth <37 weeks, SGA and LGA births were lower based on the clinical estimate of gestational age relative to that based on menstrual dating, the increases in preterm birth rate between 1990 and 2002 were fairly similar between the two measures of gestational dating. However, the decline in post‐term births was larger, based on the clinical estimate (−73.8%), than on the menstrual estimate (−36.6%) between 1990 and 2002. While the clinical estimate of gestational age appears to provide a reasonably good approximation to the menstrual estimate, disregarding the clinical estimate of gestational age may ignore the advantages of gestational age assessment in modern obstetrics.
Trends and differentials in higher‐birthweight infants at 28–31 weeks of gestation, by race and Hispanic origin, United States, 1990–2002
Authors: Kirmeyer Sharon E. W. , Martin Joyce A.
Published: September 2007

Birth certificate gestational age data based on the date of the mother's last menstrual period (LMP) are considered problematic. Of particular concern are birthweight distributions for infants reported on the birth certificate as having been delivered at 28–31 weeks' gestation; these distributions have been shown to be distinctly bimodal. The ‘second curve’ of the birthweight distribution at 28–31 weeks includes implausible birthweight/gestational age combinations and, thus, has been hypothesised to represent erroneous gestational ages due to misidentification of the date of LMP. It has been suggested that such ‘misclassification’ has declined in recent years and that this change can affect trends in preterm birth rates (<37 weeks' gestation), particularly rates among non‐Hispanic black infants. This present study used primarily simple and multivariable analyses to review trends and differentials in birthweight distributions at 28–31 weeks by race and Hispanic origin of the mother. It aggregated data for the years 1990–92 and 2000–02 from the US vital statistics Natality files.

Over the decade, the percentage of births in the second curve declined for all births and for each racial and Hispanic origin group studied. The largest decline was observed for non‐Hispanic blacks; the smallest for Hispanic births. Later initiation of prenatal care, younger maternal age, lower educational attainment, higher birth order and vaginal and singleton delivery were positively associated with a larger second curve, suggesting misclassification of gestational age. Declines in the second curve over the study period were suggested to contribute significantly to the observed decrease in overall preterm birth rates for non‐Hispanic black births. Further analysis is needed to estimate the influence of reporting error on preterm birth rates by race and Hispanic origin.
Effects of different data‐editing methods on trends in race‐specific preterm delivery rates, United States, 1990–2002
Authors: Qin Cheng , Dietz Patricia M. , England Lucinda J. , Martin Joyce A. , Callaghan William M.
Published: September 2007

In recent years, national vital statistics data indicate that the US preterm delivery rate has decreased among African Americans and increased among whites. These trends in preterm delivery rates may have been affected, in part, by improvements in the accuracy of gestational age reporting on birth certificates. Several data‐editing methods have been developed with the intention of reducing the percentage of records with misclassified gestational age. We explored whether three data‐editing methods yielded different trends in preterm delivery for years 1990–2002 among US non‐Hispanic white and non‐Hispanic African American singleton livebirths. Using National Center for Health Statistics (NCHS) public‐use data, we assessed two published methods for editing gestational age, one by Alexander et al. and the other by Zhang and Bowes (Zhang/Bowes). We also assessed a third method that substitutes the clinical estimate (CE) of gestational age when the NCHS last menstrual period (LMP)‐based estimate differs from the CE by more than 2 weeks (the LMP/CE method). The percentage of records excluded and/or reclassified by each method was calculated for years 1990, 1996 and 2002. Gestational age‐specific birthweight distributions were plotted by race for each method. Preterm delivery rates were calculated and compared by method of editing over time.

The percentage of records excluded or reclassified declined from 1990 to 2002 regardless of the method applied. For infants at 28–33 weeks' gestation using the NCHS edited data, birthweight distributions were bimodal, with the second (right‐sided) mode showing a mean birthweight consistent with that of term infants. The second mode was less pronounced using the Alexander et al. and the Zhang/Bowes methods, and was not present when the LMP/CE method was used. From 1990 to 2002, preterm delivery rates increased for non‐Hispanic whites regardless of method (range 21.3–31.3%). Preterm delivery rates increased slightly for non‐Hispanic African Americans with the LMP/CE method (1.8%), and decreased with the other methods (range 6.7–10.8%). Different approaches to editing gestational age from vital records can result in variation in preterm delivery rates and trends. Uncertainty persists around the true trends in preterm delivery, especially among African Americans. Additional research is needed to identify the approach that results in the most accurate classification of gestational age.
A comparison of LMP‐based and ultrasound‐based estimates of gestational age using linked California livebirth and prenatal screening records
Authors: Dietz Patricia M. , England Lucinda J. , Callaghan William M. , Pearl Michelle , Wier Megan L. , Kharrazi Martin
Published: September 2007

Although early ultrasound (<20 weeks' gestation) systematically underestimates the gestational age of smaller fetuses by approximately 1–2 days, this bias is relatively small compared with the large error introduced by last menstrual period (LMP) estimates of gestation, as evidenced by the number of implausible birthweight‐for‐gestational age. To characterise this misclassification, we compared gestational age estimates based on LMP from California birth certificates with those based on early ultrasound from a California linked Statewide Expanded Alpha‐fetoprotein Screening Program (XAFP). The final sample comprised 165 908 women. Birthweight distributions were plotted by gestational age; sensitivity and positive predictive value for preterm rates according to LMP were calculated using ultrasound as the ‘gold standard’.

For gestational ages 20–27 and 28–31 weeks, the LMP‐based birthweight distributions were bimodal, whereas the ultrasound‐based distributions were unimodal, but had long right tails. At 32–36 weeks, the LMP distribution was wider, flatter, and shifted to the right, compared with the ultrasound distribution. LMP vs. ultrasound estimates were, respectively, 8.7% vs. 7.9% preterm (<37 weeks), 81.2% vs. 91.0% term (37–41 weeks), and 10.1% vs. 1.1% post‐term (≥42 weeks). The sensitivity of the LMP‐based preterm birth estimate was 64.3%, and the positive predictive value was 58.7%. Overall, 17.2% of the records had estimates with an absolute difference of >14 days. The groups most likely to have inconsistent gestational age estimates included African American and Hispanic women, younger and less‐educated women, and those who entered prenatal care after the second month of pregnancy. In conclusion, we found substantial misclassification of LMP‐based gestational age.

The 2003 revised US Standard Certificate of Live Birth includes a new gestational age item, the obstetric estimate. It will be important to assess whether this estimate addresses the problems presented by LMP‐based gestational age.
StGA2ox1 is induced prior to stolon swelling and controls GA levels during potato tuber development
Authors: Kloosterman Bjorn , Navarro Christina , Bijsterbosch Gerard , Lange Theo , Prat Salomé , Visser Richard G. F. , Bachem Christian W. B.
Published: September 2007

The formation and growth of a potato (Solanum tuberosum) tuber is a complex process regulated by different environmental signals and plant hormones. In particular, the action of gibberellins (GAs) has been implicated in different aspects of potato tuber formation. Here we report on the isolation and functional analysis of a potato GA 2‐oxidase gene (StGA2ox1) and its role in tuber formation. StGA2ox1 is upregulated during the early stages of potato tuber development prior to visible swelling and is predominantly expressed in the subapical region of the stolon and growing tuber. 35S‐over‐expression transformants exhibit a dwarf phenotype, reduced stolon growth and earlier in vitro tuberization. Transgenic plants with reduced expression levels of StGA2ox1 showed normal plant growth, an altered stolon swelling phenotype and delayed in vitro tuberization. Tubers of the StGA2ox1 suppression clones contain increased levels of GA20, indicating altered GA metabolism. We propose a role for StGA2ox1 in early tuber initiation by modifying GA levels in the subapical stolon region at the onset of tuberization, thereby facilitating normal tuber development and growth.
Molecular analysis of three new receptor‐like kinase genes from hexaploid wheat and evidence for their participation in the wheat hypersensitive response to stripe rust fungus infection
Authors: Zhou Huanbin , Li Shaofang , Deng Zhiyong , Wang Xianping , Chen Tao , Zhang Jinsong , Chen Shouyi , Ling Hongqing , Zhang Aimin , Wang Daowen , Zhang Xiangqi
Published: September 2007

Considerable progress has been made in understanding the function of receptor‐like kinase (RLK) genes in model plants. However, much less is known about these genes in crop species. Here we report the characterization of three new wheat RLK genes (TaRLK‐R1, 2 and 3). The primary structure of the putative proteins TaRLK‐R1, 2 and 3 contained a signal peptide, a cysteine‐rich extracellular domain, a transmembrane domain, and a predicted intracellular kinase domain. The fusions between TaRLK‐R1, 2 or 3 and the green fluorescence protein (GFP) were targeted to the plasma membrane; such targeting required the signal peptide, extracellular domain and transmembrane domain. Transcription of TaRLK‐R1, 2 and 3 was found mainly in the green organs, and was regulated by light. Transcript levels of TaRLK‐R1, 2 and 3 increased during the hypersensitive reaction (HR) to stripe rust fungus. In addition, the TaRLK‐R3 transcript level was also upregulated by abiotic stresses. Further experiments revealed that the recombinant kinase domain of TaRLK‐R3 exhibited auto‐phosphorylation activity in vitro. Knocking down the transcript levels of TaRLK‐R1, 2 or 3 individually or all together by virus‐induced gene silencing compromised the wheat HR to stripe rust fungus. The demonstration of TaRLK‐R1, 2 and 3 as positive contributors in the wheat HR to stripe rust fungus suggests a new direction for further functional studies of this important family of RLK genes, and may facilitate the breeding of wheat varieties resistant to stripe rust disease.
TECHNICAL ADVANCE: Temperature as a determinant factor for increased and reproducible in vitro pollen germination in Arabidopsis thaliana
Authors: Boavida Leonor C. , McCormick Sheila
Published: September 2007

Despite much effort, a robust protocol for in vitro germination of Arabidopsis thaliana pollen has been elusive. Here we show that controlled temperatures, a largely disregarded factor in previous studies, and a simple optimized medium, solidified or liquid, yielded pollen germination rates above 80% and pollen tube lengths of hundreds of microns, with both Columbia and Landsberg erecta (Ler) ecotypes. We found that pollen germination and tube growth were dependent on pollen density in both liquid and solid medium. Pollen germination rates were not substantially affected by flower or plant age. The quartet1 mutation negatively affected pollen germination, especially in the Ler ecotype. This protocol will facilitate functional analyses of insertional mutants affecting male gametophyte function, and should allow detailed gene expression analyses during pollen tube growth. Arabidopsis thaliana can now be included on the list of plant species that are suitable models for physiological studies of pollen tube elongation and tip growth.
Adhesion‐related small bowel obstruction
Authors: Moran B. J.
Published: September 2007

Postoperative adhesions are the commonest cause of small bowel obstruction (SBO), a frequent surgical emergency. Adhesion obstruction is potentially lethal and a crucial aspect in management is to differentiate whether there is actual, or impending, small bowel ischaemia and therefore a need for emergency surgery. There are no completely accurate imaging or haematological techniques to exclude the requirement for surgery. Modern computerized tomography (CT) has been a significant advance in noninvasive assessment of SBO and may demonstrate the cause of the obstruction and suggest the presence of bowel ischaemia.

It is important to note that adhesions may not be the cause of SBO in a patient who has had abdominal surgery. Recurrent cancer, an obstructive colon lesion in the presence of an incompetent ileocaecal valve, an occult hernia, small bowel arterial or venous ischaemia, amongst others may be the cause and CT may elucidate some of these causes and help plan management.

Increasing utilization of laparoscopic surgery may reduce the extent and incidence of adhesions and laparoscopic adhesiolysis, in experienced hands, may be successful in managing acute obstruction or alternatively as a planned procedure when the obstruction has resolved.

Adhesive SBO remains a common surgical emergency and there is no substitute for repeated examination by a surgeon, capable of performing a laparotomy, in the optimal management of these complex patients.