bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphological and functional imaging in neurological and non‐neurological Wilson's patients
Authors: Hermann Wieland
Published: February 2014

Wilson's disease causes disturbances of the central nervous system, affecting it both directly through copper toxicity and indirectly subject to a copper‐induced hepatopathy, resulting in morphological and physiological changes in brain structures that can be captured by means of magnetic resonance imaging (MRI), 123I‐β‐CIT (2β‐carbomethoxy‐3β (4‐iodophenyl)tropane)‐SPECT (single photon emission computed tomography), 123I‐IBZM (benzamide)‐SPECT and [18F]FDG ‐PET (fluorodeoxyglucose–positron emission tomography). MRI can reveal even slight morphological changes in non‐neurological Wilson's patients. More marked findings in neurological Wilson's patients become evident in T1‐ and T2‐weighted MRI. T1‐weighted MRI predominantly detects atrophic changes, whereas T2‐weighted MRI regularly records signal changes in the putamen. With the aid of these three nuclear‐medicine examinations, nigrostriatal and metabolic disturbances are identified in neurological Wilson's patients only. Sufficient decoppering therapy prevents progression and even tends to improve symptoms. A correlation between any of the imaging findings in patients with the genetic phenotype and the incidence of the most common mutation H1069Q (homozygote or compound heterozygote) or other mutations could not be substantiated.
The Ah receptor in stem cell cycling, regulation, and quiescence
Authors: Gasiewicz Thomas A. , Singh Kameshwar P. , Bennett J. Allen
Published: February 2014

Processes that regulate quiescence, self‐renewal, and differentiation of hematopoietic stem cells (HSCs) are not well understood. Owing, in part, to the ability of xenobiotic ligands to have persistent effects on the immune system in experimental animals, there has been much work to define a physiological role of the aryl hydrocarbon receptor (AhR) and its relationship to human disease. Persistent AhR activation by dioxin, a potent agonist, results in altered numbers and function of HSCs in mice. HSCs from AhR−/− knockout (KO) mice are hyperproliferative and have an altered cell cycle. Aging KO mice show characteristics consistent with premature bone marrow exhaustion. We propose that the increased proliferation of HSCs lacking AhR expression or activity is a result of loss of quiescence, and as such, AhR normally acts as a negative regulator to curb excessive or unnecessary proliferation. Similarly, prolonged and/or inappropriate stimulation of AhR activity may compromise the ability of HSCs to sense environmental signals that allow these cells to balance quiescence, proliferation, migration, and differentiation. These data and others support a hypothesis that deregulation of AhR function has an important role in HSC regulation and in the etiology and/or progression of certain hematopoietic diseases, many of which are associated with aging.
Optimal nitrogen distribution within a leaf canopy under direct and diffuse light
Authors: HIKOSAKA KOUKI
Published: February 2014

Nitrogen distribution within a leaf canopy is an important determinant of canopy carbon gain. Previous theoretical studies have predicted that canopy photosynthesis is maximized when the amount of photosynthetic nitrogen is proportionally allocated to the absorbed light. However, most of such studies used a simple Beer's law for light extinction to calculate optimal distribution, and it is not known whether this holds true when direct and diffuse light are considered together. Here, using an analytical solution and model simulations, optimal nitrogen distribution is shown to be very different between models using Beer's law and direct–diffuse light. The presented results demonstrate that optimal nitrogen distribution under direct–diffuse light is steeper than that under diffuse light only. The whole‐canopy carbon gain is considerably increased by optimizing nitrogen distribution compared with that in actual canopies in which nitrogen distribution is not optimized. This suggests that optimization of nitrogen distribution can be an effective target trait for improving plant productivity.
Ethylene plays an essential role in the recovery of Arabidopsis during post‐anaerobiosis reoxygenation
Authors: TSAI KUEN‐JIN , CHOU SHU‐JEN , SHIH MING‐CHE
Published: February 2014

Ethylene is known to play an essential role in mediating hypoxic responses in plants. Here, we show that in addition to regulating hypoxic responses, ethylene also regulates cellular responses in the reoxygenation stage after anoxic treatment in Arabidopsis. We found that expression of several ethylene biosynthetic genes and ethylene‐responsive factors, including ERF1 and ERF2, was induced during reoxygenation. Compared with the wild type, two ethylene‐insensitive mutants (ein2‐5 and ein3eil1) were more sensitive to reoxygenation and displayed damaged phenotypes during reoxygenation. To characterize the role of ethylene, we applied microarray analysis to Col‐0, ein2‐5 and ein3eil1 under reoxygenation conditions. Our results showed that gene transcripts involved in reactive oxygen species (ROS) detoxification, dehydration response and metabolic processes were regulated during reoxygenation. Moreover, ethylene signalling may participate in regulating these responses and maintaining the homeostasis of different phytohormones. Our work presents evidence that ethylene has distinct functions in recovery after anoxia and provides insight into the reoxygenation signalling network.
Distinct responses to ozone of abaxial and adaxial stomata in three Euramerican poplar genotypes
Authors: DUMONT JENNIFER , COHEN DAVID , GÉRARD JOËLLE , JOLIVET YVES , DIZENGREMEL PIERRE , LE THIEC DIDIER
Published: February 2014

Ozone induces stomatal sluggishness, which impacts photosynthesis and transpiration. Stomatal responses to variation of environmental parameters are slowed and reduced by ozone and may be linked to difference of ozone sensitivity. Here we determine the ozone effects on stomatal conductance of each leaf surface. Potential causes of this sluggish movement, such as ultrastructural or ionic fluxes modification, were studied independently on both leaf surfaces of three Euramerican poplar genotypes differing in ozone sensitivity and in stomatal behaviour. The element contents in guard cells were linked to the gene expression of ion channels and transporters involved in stomatal movements, directly in microdissected stomata. In response to ozone, we found a decrease in the stomatal conductance of the leaf adaxial surface correlated with high calcium content in guard cells compared with a slight decrease on the abaxial surface. No ultrastructural modifications of stomata were shown except an increase in the number of mitochondria. The expression of vacuolar H+/Ca2+‐antiports (CAX1 and CAX3 homologs), β‐carbonic anhydrases (βCA1 and βCA4) and proton H+‐ATPase (AHA11) genes was strongly decreased under ozone treatment. The sensitive genotype characterized by constitutive slow stomatal response was also characterized by constitutive low expression of genes encoding vacuolar H+/Ca2+‐antiports.
An Unusual Presentation of Nickel‐Associated “School Chair Sign”
Authors: Hamann Dathan J. , Jacob Sharon E.
Published: February 2014

Symmetric sources of exposure generally result in symmetric contact dermatitis, but patient habits may distort or modify exposures in ways that may obscure clinical relevance. We present a variant of “school chair sign” consistent with the child's usual habit of sitting obliquely with her right leg crossed over her left leg.
Underwire Brassieres Are a Source of Nickel Exposure
Authors: Jacob Sharon E.
Published: February 2014

Underwire brassieres with metal rim supports are a potential source of nickel exposure to consider. Awareness and avoidance of such may also help prevent nickel sensitization.
Acute diffuse proliferative post‐infectious glomerulonephritis in renal allograft – A case report and literature review
Authors: Alsaad Khaled O. , Aloudah Nourah , AlHamdan Hanouf M. , Alamir Abdulrahman , Fakeeh Khalid
Published: February 2014

PVN is a well‐known cause of renal allograft dysfunction and failure. The diagnosis is established by examination of tissue from the renal graft, and confirmed by immunohistochemical or in situ hybridization techniques. Electron microscopy can be utilized as an ancillary modality to identify the viral particles ultrastructurally. The tubular epithelial cells are the primary target of PV cytopathic effect; however, PV‐associated glomerular changes have also been described. Immune‐type electron‐dense deposits in the TBMs have been described in the setting of PVN, and rarely, likewise have glomerular subepithelial hump‐like deposits. Diffuse immune‐mediated proliferative glomerulonephritis in the setting of PVN has not been reported before. In this report, we describe an 11‐yr‐old kidney transplant recipient boy who developed immune‐mediated glomerulonephritis with light microscopic, immunofluorescence, and ultrastructural features compatible with acute PIGN superimposing chronic PVN, discuss this unusual association and the possible mechanisms of antigen clearance in PVN and present a literature review.
Prospective pharmacokinetic study of intravenous busulfan in hematopoietic stem cell transplantation in 25 children
Authors: Okamoto Yasuhiro , Nagatoshi Yoshihisa , Kosaka Yoshiyuki , Kikuchi Akira , Kato Shunichi , Kigasawa Hisato , Horikoshi Yasuo , Oda Megumi , Kaneda Makoto , Mori Tetsuya , Mugishima Hideo , Tsuchida Masahiro , Taniguchi Shuichi , Kawano Yoshifumi
Published: February 2014

The aim of this study was to prospectively evaluate the PK and safety of ivBU in 25 Japanese children (median age six yr; range, five months–17 yr) as one of a combination of drugs in a pretransplant regimen. The patients had acute leukemia (n = 14), CML (2), JMML (5), solid tumors (2), chronic granulomatous disease (1), or metachromatic leukodystrophy (1). Five different dose schedules were used according to the patient's ABW: <9 kg (1.0 mg/kg), 9 to <16 (1.2 mg/kg), 16–23 (1.1 mg/kg), >23–34 (0.95 mg/kg), and >34 kg of BW (0.8 mg/kg). Each dose was given over two h, and sample blood was drawn at nine or 11 separate points for analysis by gas chromatography–mass spectrometry. The AUC varied from 796 to 1905 μmol min/L, and 19 of the 25 patients (76%) remained within the target range without dose adjustment. Two were diagnosed with engraftment failure. Hepatic VOD developed in four, and only one of these showed high AUC (>1500 μmol min/L). Toxicities did not correlate with the BU level. Our data showed very similar PK to those in previous studies, and these dose schedules are applicable to Japanese children.
Contractors’ and Agency Decisions and Policy Implications in A+B Bidding
Authors: Gupta Diwakar , Snir Eli M. , Chen Yibin
Published: February 2014

The focus of this study is on the A+B transportation procurement mechanism, which uses the proposed cost (A component) and the proposed time (B component) to score contractors’ bids. Empirical studies have shown that this mechanism shortens project durations. We use normative models to study the effect of certain discretionary parameters set by state transportation agencies on contractors’ equilibrium bidding strategies, winner selection, and actual completion times. We model the bidding environment in detail including multi‐dimensional bids, contractors’ uncertainty about completion times, and reputation cost. The latter refers to a private penalty that accrues to tardy contractors from increased cost of posting bonds and reduced prospects of winning future projects. Our model explains why contractors may skew line‐item bids and why winners frequently finish earlier than bid. It has several policy implications as well. For example, we recommend that agencies set the daily incentive, disincentive, and road user cost to be equal and not cap incentives. This is a departure from current practice, where incentives are often capped and weaker than penalties. Furthermore, we show that agencies may be justified in setting daily road user cost strictly smaller than the true cost of traffic disruption during construction.
Reviewing GAA‐BAP shrimp farm data to determine whether certification lessens environmental impacts
Authors: Tlusty Michael F. , Tausig Heather
Published: February 2014

The sustainable seafood movement is over a decade old. It has done much to raise awareness regarding improper production and harvest of seafood and to derive a course to lessen the deleterious environmental impacts of this industry. Certification has been a key tool, yet few programmes have demonstrated comprehensive improvements. Here, the degree of aquaculture improvement through the implementation of certification was assessed using data from the Global Aquaculture Alliance (GAA) Best Aquaculture Practice (BAP) shrimp standard. An examination of 323 audits from 192 farms spanning 2005–2012 showed that overall, 35% of the farms were conditionally certified, indicating they had to improve prior to being certified. This version of the BAP shrimp farm audit had both compliance and scored components. Out of the 28 critical points, only six were in full compliance by all farms during all audits and hence provided no value to determine farm performance. Farms that passed the audit without compliance issues had a greater aggregate scored value than those that farms with noncompliances. However, performance‐based metrics exhibited few differences between the compliant and noncompliant farms. Overall, issues pertaining to water quality were a leading cause of farms being scored as noncompliant, although they were distributed among the seven different water quality parameters. Certification systems have not been designed specifically to demonstrate adherence to continual improvement. Because of this, and the multitude of factors with which a fully compliant farm needs to acquiesce, the specific means by which certification improves aquaculture and the overall value of improvement will remain challenging to demonstrate.
A Bayesian Hierarchical Downscaling Model for South-West Western Australia Rainfall
Authors: Song Yong , Li Yun , Bates Bryson , Wikle Christopher K.
Published: February 2014

Downscaled rainfall projections from climate models are essential for many meteorological and hydrological applications. The technique presented utilizes an approach that efficiently parameterizes spatiotemporal dynamic models in terms of the close association between mean sea level pressure patterns and rainfall during winter over south-west Western Australia by means of Bayesian hierarchical modelling. This approach allows us to understand characteristics of the spatiotemporal variability of the mean sea level pressure patterns and the associated rainfall patterns. An application is presented to show the effectiveness of the technique to reconstruct present day rainfall and to predict future rainfall.
Spatial Two-Tissue Compartment Model for Dynamic Contrast-Enhanced Magnetic Resonance Imaging
Authors: Sommer Julia C. , Schmid Volker J.
Published: February 2014

In the quantitative analysis of dynamic contrast-enhanced magnetic resonance imaging compartment models allow the uptake of contrast medium to be described with biologically meaningful kinetic parameters. As simple models often fail to describe adequately the observed uptake behaviour, more complex compartment models have been proposed. However, the non-linear regression problem arising from more complex compartment models often suffers from parameter redundancy. We incorporate spatial smoothness on the kinetic parameters of a two-tissue compartment model by imposing Gaussian Markov random-field priors on them. We analyse to what extent this spatial regularization helps to avoid parameter redundancy and to obtain stable parameter point estimates per voxel. Choosing a full Bayesian approach, we obtain posteriors and point estimates by running Markov chain Monte Carlo simulations. The approach proposed is evaluated for simulated concentration time curves as well as for in vivo data from a breast cancer study.
Suicide Risk among Lesbian, Gay, Bisexual, and Transgender Military Personnel and Veterans: What Does the Literature Tell Us?
Authors: Matarazzo Bridget B. , Barnes Sean M. , Pease James L. , Russell Leah M. , Hanson Jetta E. , Soberay Kelly A. , Gutierrez Peter M.
Published: February 2014

Research suggests that both the military and veteran and the lesbian, gay, bisexual, and transgender (LGBT) populations may be at increased risk for suicide. A literature review was conducted to identify research related to suicide risk in the LGBT military and veteran populations. Despite the paucity of research directly addressing this issue, themes are discussed evident in the literature on LGBT identity and suicide risk as well as LGBT military service members and veterans. Factors such as social support and victimization appear to be particularly relevant. Suggestions are made with respect to future research that is needed on this very important and timely topic.
Quantification of capillary blood cell flow using reflectance confocal microscopy
Authors: Cinotti E. , Gergelé L. , Perrot J. L. , Dominé A. , Labeille B. , Borelli P. , Cambazard F.
Published: February 2014

Background/purpose

In vivo reflectance confocal microscopy (IVCM) is a new tool for skin microcirculation. However, the measure of quantitative blood cell flow (QBCF) has not been standardized. We studied the inter‐investigator and the intra‐capillary reproducibility of the manual measure of QBCF on IVCM videos and investigated if a software program might help measure QBCF and be sensitive to vascular occlusion tests.

Methods

The inter‐investigator reproducibility of the manual QBCF was evaluated on 107 videos. The intra‐capillary reproducibility of QBCF measured manually and by 2 semi‐automatic procedures based on Image J software analysis was evaluated on 19 capillaries. One of the semi‐automatic methods (peaks of luminous intensity) was also used to measure the QBCF during vascular occlusion tests.

Results

The manual measure did not show a good inter‐investigator reproducibility (Pearson's coefficient <0.5). The ‘peaks of luminous intensity’ method was found to have a good intra‐capillary reproducibility and to be sensitive to vascular occlusion.

Conclusion

Differently from the manual count, the count of peaks of luminous intensity by Image J software seems to be promising to measure QBCF. The future is to create software allowing for real‐time measure of the QBCF based on the peaks of luminous intensity inside the capillaries recorded by IVCM.
Repeated folding stress‐induced morphological changes in the dermal equivalent
Authors: Arai Koji Y. , Sugimoto Mami , Ito Kanako , Ogura Yuki , Akutsu Nobuko , Amano Satoshi , Adachi Eijiro , Nishiyama Toshio
Published: February 2014

Background/purpose

Repeated mechanical stresses applied to the same region of the skin are thought to induce morphological changes known as wrinkle. However, the underlying mechanisms are not fully understood. To study the mechanisms, we examined effects of repeated mechanical stress on the dermal equivalent.

Methods

We developed a novel device to apply repeated folding stress to the dermal equivalent. After applying the mechanical stress, morphological changes of the dermal equivalent and expression of several genes related to extracellular matrix turn over and cell contraction were examined.

Results

The repeated folding stress induced a noticeable decrease in the width of the dermal equivalent. The mechanical stress altered orientations of collagen fibrils. Hydroxyproline contents, dry weights and cell viability of the dermal equivalents were not affected by the mechanical stress. On the other hand, Rho‐associated coiled‐coil‐containing kinase (ROCK) specific inhibitor Y27632 completely suppressed the decrease in the width of the dermal equivalent.

Conclusion

The present results revealed that either degradation of collagen or changes in the number of cells were not responsible for the decrease in the width of the dermal equivalent and indicate that the repeated mechanical stress induces unidirectional contraction in the dermal equivalent through the RhoA‐ROCK signaling pathway.
Compositional changes of human hair melanin resulting from bleach treatment investigated by nanoscale secondary ion mass spectrometry
Authors: Kojima Toru , Yamada Hiromi , Isobe Mitsuru , Yamamoto Toshihiko , Takeuchi Miyuki , Aoki Dan , Matsushita Yasuyuki , Fukushima Kazuhiko
Published: February 2014

Background/purpose

It is important to understand the influence of bleach treatment on human hair because it is one of the most important chemical treatments in hair cosmetic processes. A comparison of the elemental composition of melanin between virgin hair and bleached hair would provide important information about the structural changes of melanin. To investigate the elemental composition of melanin granules in virgin black hair and bleached hair, these hair cross‐sections are analyzed by using a nanoscale secondary ion mass spectrometry (NanoSIMS).

Methods

The virgin black hair and bleached hair samples were embedded in resin and smooth hair cross‐sections were obtained using an ultramicrotome. NanoSIMS measurements were performed using a Cs+ primary ion beam to detect negative secondary ions.

Results

More intensive 16O− ions were detected from the melanin granules of bleached hair than from those of virgin black hair in NanoSIMS 16O− ion image. In addition, it was indicated that 16O− ion intensity and 16O‐/12C14N− ion intensity ratio of melanin granules in bleached hair were higher than those in virgin black hair.

Conclusion

Nanoscale secondary ion mass spectrometry analysis of the cross‐sections of virgin black hair and bleached hair indicated that the oxygen content in melanin granules was increased by bleach treatment.
SHUGOSHINs and PATRONUS protect meiotic centromere cohesion in Arabidopsis thaliana
Authors: Zamariola Linda , De Storme Nico , Vannerum Katrijn , Vandepoele Klaas , Armstrong Susan J. , Franklin F. Christopher H. , Geelen Danny
Published: February 2014

In meiosis, chromosome cohesion is maintained by the cohesin complex, which is released in a two‐step manner. At meiosis I, the meiosis‐specific cohesin subunit Rec8 is cleaved by the protease Separase along chromosome arms, allowing homologous chromosome segregation. Next, in meiosis II, cleavage of the remaining centromere cohesin results in separation of the sister chromatids. In eukaryotes, protection of centromeric cohesion in meiosis I is mediated by SHUGOSHINs (SGOs). The Arabidopsis genome contains two SGO homologs. Here we demonstrate that Atsgo1 mutants show a premature loss of cohesion of sister chromatid centromeres at anaphase I and that AtSGO2 partially rescues this loss of cohesion. In addition to SGOs, we characterize PATRONUS which is specifically required for the maintenance of cohesion of sister chromatid centromeres in meiosis II. In contrast to the Atsgo1 Atsgo2 double mutant, patronus T‐DNA insertion mutants only display loss of sister chromatid cohesion after meiosis I, and additionally show disorganized spindles, resulting in defects in chromosome segregation in meiosis. This leads to reduced fertility and aneuploid offspring. Furthermore, we detect aneuploidy in sporophytic tissue, indicating a role for PATRONUS in chromosome segregation in somatic cells. Thus, ploidy stability is preserved in Arabidopsis by PATRONUS during both meiosis and mitosis.
Functional analysis of chimeric lysin motif domain receptors mediating Nod factor‐induced defense signaling in Arabidopsis thaliana and chitin‐induced nodulation signaling in Lotus japonicus
Authors: Wang Wei , Xie Zhi‐Ping , Staehelin Christian
Published: February 2014

The expression of chimeric receptors in plants is a way to activate specific signaling pathways by corresponding signal molecules. Defense signaling induced by chitin from pathogens and nodulation signaling of legumes induced by rhizobial Nod factors (NFs) depend on receptors with extracellular lysin motif (LysM) domains. Here, we constructed chimeras by replacing the ectodomain of chitin elicitor receptor kinase 1 (AtCERK1) of Arabidopsis thaliana with ectodomains of NF receptors of Lotus japonicus (LjNFR1 and LjNFR5). The hybrid constructs, named LjNFR1–AtCERK1 and LjNFR5–AtCERK1, were expressed in cerk1‐2, an A. thaliana CERK1 mutant lacking chitin‐induced defense signaling. When treated with NFs from Rhizobium sp. NGR234, cerk1‐2 expressing both chimeras accumulated reactive oxygen species, expressed chitin‐responsive defense genes and showed increased resistance to Fusarium oxysporum. In contrast, expression of a single chimera showed no effects. Likewise, the ectodomains of LjNFR1 and LjNFR5 were replaced by those of OsCERK1 (Oryza sativa chitin elicitor receptor kinase 1) and OsCEBiP (O. sativa chitin elicitor‐binding protein), respectively. The chimeras, named OsCERK1–LjNFR1 and OsCEBiP–LjNFR5, were expressed in L. japonicus NF receptor mutants (nfr1‐1; nfr5‐2) carrying a GUS (β‐glucuronidase) gene under the control of the NIN (nodule inception) promoter. Upon chitin treatment, GUS activation reflecting nodulation signaling was observed in the roots of NF receptor mutants expressing both chimeras, whereas a single construct was not sufficient for activation. Hence, replacement of ectodomains in LysM domain receptors provides a way to specifically trigger NF‐induced defense signaling in non‐legumes and chitin‐induced nodulation signaling in legumes.
The tomato mutation nxd1 reveals a gene necessary for neoxanthin biosynthesis and demonstrates that violaxanthin is a sufficient precursor for abscisic acid biosynthesis
Authors: Neuman Hadar , Galpaz Navot , Cunningham Francis X. , Zamir Dani , Hirschberg Joseph
Published: February 2014

Carotenoid pigments are indispensable for plant life. They are synthesized within plastids where they provide essential functions in photosynthesis. Carotenoids serve as precursors for the synthesis of the strigolactone phytohormones, which are made from β‐carotene, and of abscisic acid (ABA), which is produced from certain xanthophylls. Despite the significant progress that has been made in our understanding of the carotenoid biosynthesis pathway, the synthesis of the xanthophyll neoxanthin has remained unknown. We report here on the isolation of a tomato (Solanum lycopersicum) mutant, neoxanthin‐deficient 1 (nxd1), which lacks neoxanthin, and on the cloning of a gene that is necessary for neoxanthin synthesis in both tomato and Arabidopsis. The locus nxd1 encodes a gene of unknown function that is conserved in all higher plants. The activity of NXD1 is essential but cannot solely support neoxanthin synthesis. Lack of neoxanthin does not significantly reduce the fitness of tomato plants in cultivated field conditions and does not impair the synthesis of ABA, suggesting that in tomato violaxanthin is a sufficient precursor for ABA production in vivo.
Pollen tube NAD(P)H oxidases act as a speed control to dampen growth rate oscillations during polarized cell growth
Authors: Lassig Roman , Gutermuth Timo , Bey Till D. , Konrad Kai R. , Romeis Tina
Published: February 2014

Reactive oxygen species (ROS) produced by NAD(P)H oxidases play a central role in plant stress responses and development. To better understand the function of NAD(P)H oxidases in plant development, we characterized the Arabidopsis thaliana NAD(P)H oxidases RBOHH and RBOHJ. Both proteins were specifically expressed in pollen and dynamically targeted to distinct and overlapping plasma membrane domains at the pollen tube tip. Functional loss of RBOHH and RBOHJ in homozygous double mutants resulted in reduced fertility. Analyses of pollen tube growth revealed remarkable differences in growth dynamics between Col–0 and rbohh–1 rbohj–2 pollen tubes. Growth rate oscillations of rbohh–1 rbohj–2 pollen tubes showed strong fluctuations in amplitude and frequency, ultimately leading to pollen tube collapse. Prior to disintegration, rbohh–1 rbohj–2 pollen tubes exhibit high‐frequency growth oscillations, with significantly elevated growth rates, suggesting that an increase in the rate of cell‐wall exocytosis precedes pollen tube collapse. Time‐lapse imaging of exocytic dynamics revealed that NAD(P)H oxidases slow down pollen tube growth to coordinate the rate of cell expansion with the rate of exocytosis, thereby dampening the amplitude of intrinsic growth oscillations. Using the Ca2+ reporter Yellow Cameleon 3.6, we demonstrate that high‐amplitude growth rate oscillations in rbohh–1 rbohj–2 pollen tubes are correlated with growth‐dependent Ca2+ bursts. Electrophysiological experiments involving double mutant pollen tubes and pharmacological treatments also showed that ROS influence K+ homeostasis. Our results indicate that, by limiting pollen tube growth, ROS produced by NAD(P)H oxidases modulate the amplitude and frequency of pollen tube growth rate oscillations.
TaADF7, an actin‐depolymerizing factor, contributes to wheat resistance against Puccinia striiformis f. sp. tritici
Authors: Fu Yanping , Duan Xiaoyuan , Tang Chunlei , Li Xiaorui , Voegele Ralf T. , Wang Xiaojie , Wei Guorong , Kang Zhensheng
Published: February 2014

The actin cytoskeleton is involved in plant defense responses; however, the role of the actin‐depolymerizing factor (ADF) family, which regulates actin cytoskeletal dynamics, in plant disease resistance, is largely unknown. Here, we characterized a wheat (Triticum aestivum) ADF gene, TaADF7, with three copies located on chromosomes 1A, 1B, and 1D, respectively. All three copies encoded the same protein, although there were variations in 19 nucleotide positions in the open reading frame. Transcriptional expression of the three TaADF7 copies were all sharply elevated in response to avirulent Puccinia striiformis f. sp. tritici (Pst) infection, with similar expression patterns. TaADF7 regulated the actin cytoskeletal dynamics by targeting the actin cytoskeleton to execute actin binding/severing activities. When the TaADF7 copies were all silenced by virus‐induced gene silencing, the growth of Pst hypha increased and sporadic urediniospores were observed, as compared with control plants, upon inoculation with avirulent Pst. In addition, the accumulation of reactive oxygen species (ROS) and the hypersensitive response (HR) were greatly weakened, whereas cytochalasin B partially rescued the HR in TaADF7 knock‐down plants. Together, these findings suggest that TaADF7 is likely to contribute to wheat resistance against Pst infection by modulating the actin cytoskeletal dynamics to influence ROS accumulation and the HR.
Cytokinin signaling stabilizes the response activator ARR1
Authors: Kurepa Jasmina , Li Yan , Smalle Jan A.
Published: February 2014

The cytokinins play essential roles in the development and environmental responses of higher plants. Cytokinin signaling leads to the phosphorylation‐dependent activation of two classes of Arabidopsis response regulators (RRs): the type‐B RR (RRB) transcriptional activators that promote the expression of cytokinin response genes and the type‐A RRs (RRAs) that are encoded by primary cytokinin response genes and function as response inhibitors. We show that cytokinin signaling increases the abundance of ARR1, a ubiquitously expressed RRB, by preventing its degradation by the 26S proteasome. We also show that the RRAs act to suppress ARR1 accumulation, thus providing an explanation for their inhibitory action in cytokinin signaling. Collectively, our results reveal an additional regulatory mechanism in the cytokinin response pathway that involves the cytokinin‐dependent stability control of a major RRB response activator.
Consequences of state transitions on the structural and functional organization of Photosystem I in the green alga Chlamydomonas reinhardtii
Authors: Drop Bartlomiej , Yadav K.N. Sathish , Boekema Egbert J. , Croce Roberta
Published: February 2014

State transitions represent a photoacclimation process that regulates the light‐driven photosynthetic reactions in response to changes in light quality/quantity. It balances the excitation between photosystem I (PSI) and II (PSII) by shuttling LHCII, the main light‐harvesting complex of green algae and plants, between them. This process is particularly important in Chlamydomonas reinhardtii in which it is suggested to induce a large reorganization in the thylakoid membrane. Phosphorylation has been shown to be necessary for state transitions and the LHCII kinase has been identified. However, the consequences of state transitions on the structural organization and the functionality of the photosystems have not yet been elucidated. This situation is mainly because the purification of the supercomplexes has proved to be particularly difficult, thus preventing structural and functional studies. Here, we have purified and analysed PSI and PSII supercomplexes of C. reinhardtii in states 1 and 2, and have studied them using biochemical, spectroscopic and structural methods. It is shown that PSI in state 2 is able to bind two LHCII trimers that contain all four LHCII types, and one monomer, most likely CP29, in addition to its nine Lhcas. This structure is the largest PSI complex ever observed, having an antenna size of 340 Chls/P700. Moreover, all PSI‐bound Lhcs are efficient in transferring energy to PSI. A projection map at 20 Å resolution reveals the structural organization of the complex. Surprisingly, only LHCII type I, II and IV are phosphorylated when associated with PSI, while LHCII type III and CP29 are not, but CP29 is phosphorylated when associated with PSII in state2.
Kinase activity and calmodulin binding are essential for growth signaling by the phytosulfokine receptor PSKR1
Authors: Hartmann Jens , Fischer Cornelia , Dietrich Petra , Sauter Margret
Published: February 2014

The cell growth‐promoting peptide phytosulfokine (PSK) is perceived by leucine‐rich repeat (LRR) receptor kinases. To elucidate PSK receptor function we analyzed PSKR1 kinase activity and binding to Ca2+ sensors and evaluated the contribution of these activities to growth control in planta. Ectopically expressed PSKR1 was capable of auto‐ and transphosphorylation. Replacement of a conserved lysine within the ATP‐binding region by a glutamate resulted in the inhibition of auto‐ and transphosphorylation kinase activities. Expression of the kinase‐inactive PSKR1(K762E) receptor in the pskr null background did not restore root or shoot growth. Instead, the mutant phenotype was enhanced suggesting that the inactive receptor protein exerts growth‐inhibitory activity. Bioinformatic analysis predicted a putative calmodulin (CaM)‐binding site within PSKR1 kinase subdomain VIa. Bimolecular fluorescence complementation analysis demonstrated that PSKR1 binds to all isoforms of CaM, more weakly to the CaM‐like protein CML8 but apparently not to CML9. Mutation of a conserved tryptophan (W831S) within the predicted CaM‐binding site strongly reduced CaM binding. Expression of PSKR1(W831S) in the pskr null background resulted in growth inhibition that was similar to that of the kinase‐inactive receptor. We conclude that PSK signaling requires Ca2+/CaM binding and kinase activity of PSKR1 in planta. We further propose that the inactivated kinase interferes with other growth‐promoting signaling pathway(s).
Targeting novel chemical and constitutive primed metabolites against Plectosphaerella cucumerina
Authors: Gamir Jordi , Pastor Victoria , Kaever Alexander , Cerezo Miguel , Flors Victor
Published: February 2014

Priming is a physiological state for protection of plants against a broad range of pathogens, and is achieved through stimulation of the plant immune system. Various stimuli, such as beneficial microbes and chemical induction, activate defense priming. In the present study, we demonstrate that impairment of the high‐affinity nitrate transporter 2.1 (encoded by NRT2.1) enables Arabidopsis to respond more quickly and strongly to Plectosphaerella cucumerina attack, leading to enhanced resistance. The Arabidopsis thaliana mutant lin1 (affected in NRT2.1) is a priming mutant that displays constitutive resistance to this necrotroph, with no associated developmental or growth costs. Chemically induced priming by β–aminobutyric acid treatment, the constitutive priming mutant ocp3 and the constitutive priming present in the lin1 mutant result in a common metabolic profile within the same plant–pathogen interactions. The defense priming significantly affects sugar metabolism, cell‐wall remodeling and shikimic acid derivatives levels, and results in specific changes in the amino acid profile and three specific branches of Trp metabolism, particularly accumulation of indole acetic acid, indole‐3–carboxaldehyde and camalexin, but not the indolic glucosinolates. Metabolomic analysis facilitated identification of three metabolites in the priming fingerprint: galacturonic acid, indole‐3–carboxylic acid and hypoxanthine. Treatment of plants with the latter two metabolites by soil drenching induced resistance against P. cucumerina, demonstrating that these compounds are key components of defense priming against this necrotrophic fungus. Here we demonstrate that indole‐3–carboxylic acid induces resistance by promoting papillae deposition and H2O2 production, and that this is independent of PR1, VSP2 and PDF1.2 priming.
Management of roadside populations of invasive Ambrosia artemisiifolia by mowing
Authors: Milakovic I , Fiedler K , Karrer G
Published: February 2014

Ambrosia artemisiifolia (common ragweed) is a highly allergenic alien weed in Europe, which spreads rapidly along roadsides. Road verges are subject to frequent mowing, which further increases the spreading of the plants' seeds. Ambrosia artemisiifolia reacts to cutting by producing new shoots, which are able to develop flowers and ultimately new seeds. An effective mowing regime that would decrease the production of seeds and their dispersal is desirable to control the spread of the plant, but an appropriate way of mowing has yet to be found. In this study, we explored how the reproductive traits of A. artemisiifolia plants in seven spontaneous roadside populations reacted to the application of different mowing regimes over 3 years. The mowing regimes that were applied differed in the timing and frequency of cuttings. We found that the cutting regime, if appropriately timed, can strongly influence the production of male inflorescences (i.e. allergenic pollen), of female flowers (i.e. seeds) and had an impact on the phenological development of the plant. Based on our findings, we suggest that the optimal management of the plant along roadsides must be adjusted to its phenological development. The most effective mowing method of control consists of a first cut shortly before male flowering, to limit the quantities of released pollen, followed by subsequent cuts before the onset of new flowers on the resprouting lateral shoots.
Nonfragile Guaranteed Cost Control of Discrete-Time Fuzzy Bilinear System With Time-Delay
Authors: Zhang Guo , Li Jun-Min , Ge Yun-Wang
Published: February 2014

This paper focuses on the problem of nonfragile guaranteed cost control for a class of T-S discrete-time fuzzy bilinear systems (DFBS) with time-delay in both states and inputs. Based on the parallel distributed compensation approach, the sufficient conditions are derived such that the closed-loop system is asymptotically stable and the closed-loop performance is no more than a certain upper bound in the presence of the additive controller gain perturbations.
Intermittent Failures in Hardware and Software
Authors: Bakhshi Roozbeh , Kunche Surya , Pecht Michael
Published: February 2014

Intermittent failures and no fault found (NFF) phenomena are a concern in electronic systems because of their unpredictable nature and irregular occurrence. They can impose significant costs for companies, damage the reputation of a company, or be catastrophic in systems such as nuclear plants or avionics. Intermittent failures in systems can be attributed to hardware failures or software failures. In order to diagnose and mitigate the intermittent failures in systems, the nature and the root cause of these failures have to be understood. In this paper we have reviewed the current literature concerning intermittent failures and have a comprehensive study on how these failures happen, how to detect them and how to mitigate them.
The Influence of Partial and Full Thickness Tears on Infraspinatus Tendon Strain Patterns
Authors: Frisch Kayt E. , Marcu David , Baer Geoffrey S. , Thelen Darryl G. , Vanderby Ray
Published: February 2014

Tears on the bursal and articular sides of the rotator cuff tendons are known to behave differently and strain is thought to play a role in this difference. This study investigates the effect of tear location on the changes in three strain measurements (grip-to-grip, insertion, and mid-substance tissue) in a sheep infraspinatus tendon model during axial loading. We introduced a 14 mm wide defect near the insertion from either the articular or bursal side of the tendon to three depths (3 mm, 7 mm & full) progressively. For each condition, tendons were sinusoidally stretched (4% at 0.5 Hz) while insertion and mid-substance strains were tracked with surface markers. For a fixed load, grip-to-grip strain increased significantly compared to intact for both cuts. Insertion strain increased significantly for the bursal-side defect immediately but not for the articular-side until the 66% cut. Mid-substance tissue strain showed no significant change for partial thickness articular-side defects and a significant decrease for bursal-side defects after the 66% cut. All full thickness cuts exhibited negligible mid-substance tissue strain change. Our results suggest that the tendon strain patterns are more sensitive to defects on the bursal side, and that partial thickness tears tend to induce localized strain concentrations in regions adjacent to the damaged tissue.
A Model for Quantifying System Evolvability Based on Excess and Capacity
Authors: Tackett Morgan W. P. , Mattson Christopher A. , Ferguson Scott M.
Published: February 2014

An important factor in system longevity is service-phase evolvability, which is defined as the ability of a system to physically transform from one configuration to a more desirable configuration while in service. These transformations may or may not be known during the design process, and may or may not be reversible. In a different study, we examined 210 engineered systems and found that system excess and modularity allow a system to evolve while in service. Building on this observation, the present paper introduces mathematical relationships that map a system's excess to that system's ability to evolve. As introduced in this paper, this relationship is derived from elastic potential-energy theories. The use of the evolvability measure, and other related measures presented herein, are illustrated with simple examples and applied to the design of U.S. Navy nuclear aircraft carriers. Using these relationships, we show that the Navy's new Ford-class aircraft carrier is measurably more evolvable than the Nimitz-class carriers. While the ability for systems to evolve is based on excess and modularity, this paper is focused only on excess. The mapping between modularity and evolvability is the focus of another work by the authors.
Efficient Assessment of Structural Reliability in Presence of Random and Fuzzy Uncertainties
Authors: Balu A. S. , Rao B. N.
Published: February 2014

This paper presents an efficient uncertainty analysis for estimating the possibility distribution of structural reliability in presence of mixed uncertain variables. The proposed method involves high dimensional model representation for the limit state function approximation, transformation technique to obtain the contribution of the fuzzy variables to the convolution integral and fast Fourier transform for solving the convolution integral. In this methodology, efforts are required in evaluating conditional responses at a selected input determined by sample points, as compared to full scale simulation methods, thus the computational efficiency is accomplished. The proposed method is applicable for structural reliability estimation involving any number of fuzzy and random variables with any kind of distribution.
Behavior of Compressive Residual Stresses in High Strength Steel Welds Induced by High Frequency Mechanical Impact Treatment
Authors: Khurshid Mansoor , Barsoum Zuheir , Marquis Gary
Published: February 2014

Residual stress state plays an important role in the fatigue life of welded structures. The effect can be beneficial or detrimental, depending on the nature of residual stresses. High frequency mechanical impact (HFMI) treatment is a postweld fatigue improvement technique for welded joints. In this research work the behavior of compressive residual stresses induced in welded joints in high strength steels (HSS) by HFMI treatment has been investigated. Longitudinal nonload carrying attachments in HSS are tested with constant amplitude (CA) and variable amplitude (VA) fatigue loading. Stress concentration factors have been calculated using finite element analysis (FEA). Residual stresses have been measured at different cycles during fatigue testing using X-ray diffraction technique. It is observed that the induced residual stresses are quite stable with some relaxation in CA and VA loading. The overloads in VA loading seem to be more detrimental. Relaxation of residual stresses is more obvious in VA tests.
Reduced Order Impedance Models of Lithium Ion Batteries
Authors: Prasad Githin K. , Rahn Christopher D.
Published: February 2014

This paper develops reduced order, linear models of lithium ion batteries that can be used for model-based power train simulation, design, estimation, and controlling in hybrid and electric vehicles (HEV). First, a reduced order model is derived from the fundamental governing electrochemical charge and Li+ conservation equations that are linearized at the operating state of charge and low current density. The equations are solved using analytical and numerical techniques to produce the transcendental impedance or transfer function from input current to output voltage. This model is then reduced to a low order state space model using a system identification technique based on least squares optimization. Given the prescribed current, the model predicts voltage and other variables such as electrolyte and electrode surface concentration distributions. The second model is developed by neglecting electrolyte diffusion and modeling each electrode with a single active material particle. The transcendental particle transfer functions are discretized using a Padé Approximation. The explicit form of the single particle model impedance can be realized by an equivalent circuit with resistances and capacitances related to the cell parameters. Both models are then tuned to match experimental electrochemical impedance spectroscopy (EIS) and pulse current-voltage data.
Semistability Analysis of the Chaplygin Sleigh and Nonsmooth Mechanical Oscillator
Authors: Pushpak N. Sai , Mahindrakar Arun D. , Ekbote Anup
Published: February 2014

An appropriate notion for stability studies of dynamical systems with a continuum of equilibria is semistability. One approach to semistability investigation is based on the nontangency between the vector field and the set of equilibria. In this work, we introduce a novel way of verifying nontangency by computing an outer estimate of the direction cone and illustrate its application through two well-known second-order systems. The stable equilibria of both the systems are shown to possess the semistability property.