bluuebunny/crossref_metadata_2025 huggingface dataset:
Extrinsic effects on dielectric response of ultrafine grain BaTiO3 ceramics
Authors: Zhang Haitao , Deng Xiangyun , Li Ting , Zhang Wen , Chen Rike , Tian Wenwei , Li Jianbao , Wang Xiaohui , Li Longtu
Published: October 2010

The complex dielectric response of ultrafine grain barium titanate ceramics is investigated using broadband dielectric spectrometer. Extrinsic effects like conduction, space charge associating with grain boundaries are discussed. One dielectric relaxation ascribes to the interaction of defects with grain boundaries, for which the activation energy fitted by Arrhenius equation is equivalent to 0.26 eV and the value shifts to 0.41 eV after annealing treatment. Another relaxation phenomenon locating at elevated temperature can be attributed to interfacial polarization due to space charge accumulation effect. The study of complex impedance spectra suggests that grain boundary effects support extrinsic mechanism.
Anomaly in the conductivity relaxation parameters at the phase transition of ferroelectric materials: A time domain study
Authors: Leyet Y. , Guerrero F. , Amorín H. , Guerra J. de Los S. , Eiras J. A.
Published: October 2010

The influence of the ferroelectric to paraelectric transition on the relaxation parameters of conductive processes in ferroelectric materials is studied in the time domain. Three well-known ferroelectric systems were chosen with transition temperatures in different regions, these are, high-temperature PbNb2O6-based ceramics; nanostructured Pb(Zr0.6Ti0.4)O3 ceramics; and submicron BaTiO3. The thermal evolution of relaxation parameters shows clear anomalies in their typical behavior when conductivity processes arise in the temperature range where the ferroelectric transition takes place. The method here described allows obtaining information about the correlation between charge transport and the motion of the off-center ions at the phase transition.
Desiccation of leaves after de-submergence is one cause for intolerance to complete submergence of the rice cultivar IR 42
Authors: Setter Timothy L. , Bhekasut Panatda , Greenway Hank
Published: October 2010

This paper presents evidence that severe water deficits, following de-submergence after flash flooding of rice, contribute to submergence intolerance of IR 42, a rice cultivar that rapidly elongates during submergence. In glasshouse experiments, 13-day-old rice seedlings were completely submerged for 3–5 days. The main experiments were with IR 42, a cultivar intolerant to transient complete submergence. During submergence the 3rd leaf expanded, and after 5 days submergence its sheath was 4-fold longer than in non-submerged seedlings. After de-submergence, this leaf rapidly desiccated, its water potential dropped below –2 MPa, while the stomatal conductance was very low. Excision experiments showed the water deficits after de-submergence were due mainly to a large reduction in the hydraulic conductivity in the leaf sheath. The water deficits are an important cause in the sequence of events rather than a mere result of injury: when plants were de-submerged at 100% rather than at 50% RH, water potentials remained high. However, when, after another 5 days, these plants were transferred to 50% RH, the 3rd leaf rapidly desiccated, indicating little repair of the lesion causing the low hydraulic conductivity.
Imperfect dark energy from kinetic gravity braiding
Authors: Cédric Deffayet  , Oriol Pujolàs  , Ignacy Sawicki  , Alexander Vikman
Published: October 2010

We introduce a large class of scalar-tensor models with interactions containing the second derivatives of the scalar field but not leading to additional degrees of freedom. These models exhibit peculiar features, such as an essential mixing of scalar and tensor kinetic terms, which we have namedkinetic braiding. This braiding causes the scalar stress tensor to deviate from the perfect-fluid form. Cosmology in these models possesses a rich phenomenology, even in the limit where the scalar is an exact Goldstone boson. Generically, there are attractor solutions where the scalar monitors the behaviour of external matter. Because of thekinetic braiding, the position of the attractor depends both on the form of the Lagrangian and on the external energy density. The late-time asymptotic of these cosmologies is a de Sitter state. The scalar can exhibit phantom behaviour and is able to cross the phantom divide with neither ghosts nor gradient instabilities. These features provide a new class of models for Dark Energy. As an example, we study in detail a simple one-parameter model. The possible observational signatures of this model include a sizeable Early Dark Energy and a specific equation of state evolving into the final de-Sitter state from a healthy phantom regime.
Modelling the effect of structural QSAR parameters on skin penetration using genetic programming
Authors: Chung K K , Do D Q
Published: October 2010

In order to model relationships between chemical structures and biological effects in quantitative structure–activity relationship (QSAR) data, an alternative technique of artificial intelligence computing—genetic programming (GP)—was investigated and compared to the traditional method—statistical. GP, with the primary advantage of generating mathematical equations, was employed to model QSAR data and to define the most important molecular descriptions in QSAR data. The models predicted by GP agreed with the statistical results, and the most predictive models of GP were significantly improved when compared to the statistical models using ANOVA. Recently, artificial intelligence techniques have been applied widely to analyse QSAR data. With the capability of generating mathematical equations, GP can be considered as an effective and efficient method for modelling QSAR data.
Glucose oxidase immobilization on different modified surfaces of platinum nanowire for application in glucose detection
Authors: Le Thi Thanh Tuyen , Tran Phu Duy , Pham Xuan Tung , Tong Duy Hien , Dang Mau Chien
Published: October 2010

In this work, the surface of platinum (Pt) nanowires was modified by using several chemicals, including a compound of gelatin gel with SiO
2, polyvinyl alcohol (PVA) with Prussian blue (PB) mediator and cysteamine self-assembled monolayers (SAM). Then, glucose oxidase (GOD) enzyme was immobilized on the modified surfaces of Pt nanowire electrodes by using techniques of electrochemical adsorption and chemical binding. The GOD immobilized Pt nanowires were used for application in glucose detection by performing a cyclic voltammetry measurement. The detection results showed that GOD was immobilized on all of the tested surfaces and the highest glucose detection sensitivity of 60 μM was obtained when the Pt nanowires were modified by PVA with PB mediator. Moreover, the sensors showed very high current response when the Pt nanowires were modified with the cysteamine SAM. The stability and catalyst activity of GOD are also reported here. For instance, the catalyst activity of GOD retained about 60% of its initial value after it was stored at 4 °C in a 100 mM PBS buffer solution with a pH of 7.2 for a period of 30 days.
Does Erythrocyte Blood Transfusion Prevent Acute Kidney Injury?
Authors: Engoren Milo
Published: October 2010

Background

Acute kidney injury is a common occurrence in intensive care unit patients with a reported incidence of 11-67% and is associated with an increased risk of death. In other patient populations, erythrocyte transfusion has been associated with increased risk of adverse outcomes including sepsis, multisystem organ dysfunction, and death. The purpose of this study was to determine the effect of erythrocyte transfusion on the development of acute kidney injury.

Methods

This was a retrospective analysis of prospectively collected data that used propensity matched transfused and nontransfused patients. Propensity matching was done using semiparsimonious logistic regression. McNemar test for nonindependent data sets was used to compare groups.

Results

Four hundred two patients from a trial on fluid management in patients with acute lung injury were matched. 38% of transfused patients had a rise in creatinine the day after transfusion compared with 33% of their nontransfused matches (P = 0.315). By day 7, creatinine had increased in 51% of transfused patients compared with 52% in nontransfused patients (P = 0.832). The incidences of renal risk, injury, and failure were 39 (19%), 27 (13%), and 11 (5%) in the transfused group and 38 (19%), 24 (12%), and 11 (5%) in the nontransfused group, P = 1.00, 0.785, and 1.00, respectively.

Conclusions

Transfusion of erythrocytes to patients with acute lung injury had no effect on the development of acute kidney injury.
Femoral Nerve Block Improves Analgesia Outcomes after Total Knee Arthroplasty
Authors: Paul James E. , Arya Aman , Hurlburt Lindsay , Cheng Ji , Thabane Lehana , Tidy Antonella , Murthy Yamini
Published: October 2010

Background

Femoral nerve blockade (FNB) is a common method of analgesia for postoperative pain control after total knee arthroplasty. We conducted a systematic review to compare the analgesia outcomes in randomized controlled trials that compared FNB (with and without sciatic nerve block) with epidural and patient-controlled analgesia (PCA).

Methods

We identified 23 randomized controlled trials that compared FNB with PCA or epidural analgesia. These studies included 1,016 patients, 665 with FNB, 161 with epidural, and 190 with PCA alone.

Results

All 10 studies of single-shot FNB (SSFNB) used concurrent PCA opioids. SSFNB was found to reduce PCA morphine consumption at 24 h (-19.9 mg, 95% credible interval [CrI]: -35.2 to -4.6) and 48 h (-38.0 mg, 95% CrI: -56.0 to -19.7), pain scores with activity (but not at rest) at 24 and 48 h (-1.8 visual analog pain scale, 95% CrI: -3.3 to -0.02 at 24 h; -1.5 visual analog pain scale, 95% CrI: -2.9 to -0.02 at 48 h) and reduce the incidence of nausea (0.37 odds ratio, 95% CrI: 0.1 to 0.9) compared with PCA alone. SSFNB had similar morphine consumption and pain scores compared with SSFNB plus sciatic nerve block, and SSFNB plus continuous FNB.

Conclusions

SSFNB or continuous FNB (plus PCA) was found to be superior to PCA alone for postoperative analgesia for patients having total knee arthroplasty. The impact of adding a sciatic block or continuous FNB to a SSFNB needs to be studied further.
Short-term Memory Impairment after Isoflurane in Mice Is Prevented by the α5 γ-Aminobutyric Acid Type A Receptor Inverse Agonist L-655,708
Authors: Saab Bechara J. , MacLean Ashley J. B. , Kanisek Marijana , Zurek Agnieszka A. , Martin Loren J. , Roder John C. , Orser Beverley A.
Published: October 2010

Background

Memory blockade is an essential component of the anesthetic state. However, postanesthesia memory deficits represent an undesirable and poorly understood adverse effect. Inhibitory α5 subunit-containing γ-aminobutyric acid subtype A receptors (α5GABAA) are known to play a critical role in memory processes and are highly sensitive to positive modulation by anesthetics. We postulated that inhibiting the activity of α5GABAA receptors during isoflurane anesthesia would prevent memory deficits in the early postanesthesia period.

Methods

Mice were pretreated with L-655,708, an α5GABAA receptor-selective inverse agonist, or vehicle. They were then exposed to isoflurane for 1 h (1.3%, or 1 minimum alveolar concentration, or air-oxygen control). Then, either 1 or 24 h later, mice were conditioned in fear-associated contextual and cued learning paradigms. In addition, the effect of L-655,708 on the immobilizing dose of isoflurane was studied. Motor coordination, sedation, anxiety, and the concentration of isoflurane in the brain at 5 min, 1 h, and 24 h after isoflurane were also examined.

Results

Motor and sensory function recovered within minutes after termination of isoflurane administration. In contrast, a robust deficit in contextual fear memory persisted for at least 24 h. The α5GABAA receptor inverse agonist, L-655,708, completely prevented memory deficits without changing the immobilizing dose of isoflurane. Trace concentrations of isoflurane were measured in the brain 24 h after treatment.

Conclusions

Memory deficits occurred long after the sedative, analgesic, and anxiolytic effects of isoflurane subsided. L-655,708 prevented memory deficit, suggesting that an isoflurane interaction at α5GABAA receptors contributes to memory impairment during the early postanesthesia period.
Broadly Applicable Risk Stratification System for Predicting Duration of Hospitalization and Mortality
Authors: Sessler Daniel I. , Sigl Jeffrey C. , Manberg Paul J. , Kelley Scott D. , Schubert Armin , Chamoun Nassib G.
Published: October 2010

Background

Hospitals are increasingly required to publicly report outcomes, yet performance is best interpreted in the context of population and procedural risk. We sought to develop a risk-adjustment method using administrative claims data to assess both national-level and hospital-specific performance.

Methods

A total of 35,179,507 patient stay records from 2001-2006 Medicare Provider Analysis and Review (MEDPAR) files were randomly divided into development and validation sets. Risk stratification indices (RSIs) for length of stay and mortality endpoints were derived from aggregate risk associated with individual diagnostic and procedure codes. Performance of RSIs were tested prospectively on the validation database, as well as a single institution registry of 103,324 adult surgical patients, and compared with the Charlson comorbidity index, which was designed to predict 1-yr mortality. The primary outcome was the C statistic indicating the discriminatory power of alternative risk-adjustment methods for prediction of outcome measures.

Results

A single risk-stratification model predicted 30-day and 1-yr postdischarge mortality; separate risk-stratification models predicted length of stay and in-hospital mortality. The RSIs performed well on the national dataset (C statistics for median length of stay and 30-day mortality were 0.86 and 0.84). They performed significantly better than the Charlson comorbidity index on the Cleveland Clinic registry for all outcomes. The C statistics for the RSIs and Charlson comorbidity index were 0.89 versus 0.60 for median length of stay, 0.98 versus 0.65 for in-hospital mortality, 0.85 versus 0.76 for 30-day mortality, and 0.83 versus 0.77 for 1-yr mortality. Addition of demographic information only slightly improved performance of the RSI.

Conclusion

RSI is a broadly applicable and robust system for assessing hospital length of stay and mortality for groups of surgical patients based solely on administrative data.
Plasticicumulans acidivorans gen. nov., sp. nov., a polyhydroxyalkanoate-accumulating gammaproteobacterium from a sequencing-batch bioreactor
Authors: Jiang Yang , Sorokin Dimitry Yu. , Kleerebezem Robbert , Muyzer Gerard , van Loosdrecht Mark
Published: October 2010

Here, we describe a novel bacterium, strain TUD-YJ37T, which can accumulate polyhydroxybutyrate (PHB) to more than 85 % (w/w) dry cell weight. The bacterium was isolated from a mixed-culture bioreactor by using a feast–famine regime and its properties were characterized. Phylogenetic analysis based on full 16S rRNA gene sequences revealed that the isolate is a member of the Gammaproteobacteria, forming an independent, deep phylogenetic lineage. It is most closely related to members of the genera Methylocaldum, Methylococcus and Natronocella, with sequence similarities below 91 %. Strain TUD-YJ37T was an obligately aerobic, ovoid, Gram-negative bacterium, motile by means of a polar flagellum. It utilized C2–C10 fatty acids as carbon and energy sources. The temperature range for growth was 20–35 °C, with an optimum of 30 °C; the pH range was 6.0–8.0, without a clear optimum. The major respiratory quinone was Q-8. Polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three unidentified phospholipids, an unidentified aminolipid and another unidentified lipid. The predominant fatty acids in the membrane polar lipids were C16 : 1ω7c, C16 : 0 and C18 : 1ω7c. The G+C content of the genomic DNA was 67.4 mol%. On the basis of phenotypic, chemotaxonomic and molecular data, the isolate is proposed to represent a novel genus and species, for which the name Plasticicumulans acidivorans gen. nov., sp. nov. is proposed. The type strain of Plasticicumulans acidivorans is TUD-YJ37T ( = DSM 23606T  = CBS 122990T).
Proposal of Solimonas aquatica sp. nov., reclassification of Sinobacter flavus Zhou et al. 2008 as Solimonas flava comb. nov. and Singularimonas variicoloris Friedrich and Lipski 2008 as Solimonas variicoloris comb. nov. and emended descriptions of the genus Solimonas and its type species Solimonas soli
Authors: Sheu Shih-Yi , Cho Nian-Tsz , Arun A. B. , Chen Wen-Ming
Published: October 2010

A bacterial strain designated NAA16T was isolated from a freshwater spring in Taiwan and was characterized using a polyphasic taxonomic approach. Strain NAA16T was aerobic, Gram-staining-negative, rod-shaped, non-spore-forming and motile by means of a single polar flagellum. Growth occurred at 20–40 °C (optimum, 25 °C), at pH 7.0–8.0 (optimum, pH 7.5) and with up to 1 % NaCl (optimum, 0.5 %). Phylogenetic analyses based on 16S rRNA gene sequences showed that the closest relatives of strain NAA16T were Singularimonas variicoloris MN28T, Sinobacter flavus CW-KD 4T and Solimonas soli DCY12T, with respective sequence similarities of 96.7, 96.6 and 96.2 %. Phylogenetic trees reconstructed from 16S rRNA gene or rpoB sequences (encoding the β-subunit of the RNA polymerase) revealed that the novel strain NAA16T and these three closest relatives formed an independent phylogenetic clade within the Gammaproteobacteria. Strain NAA16T contained C16 : 0, C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) as predominant fatty acids and possessed phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an uncharacterized aminophospholipid as dominant polar lipids. The major isoprenoid quinone was Q-8. The DNA G+C content of strain NAA16T was 66.2 mol%. The taxonomic relationship of strain NAA16T, Singularimonas variicoloris DSM 15731T, Sinobacter flavus DSM 18980T and Solimonas soli LMG 24014T was clarified by means of a direct experimental comparison. Based on phenotypic, chemotaxonomic and phylogenetic data, the descriptions of the genus Solimonas and its type species Solimonas soli are emended. Members of the genus are Gram-negative, oxidase- and catalase-positive, aerobic or facultatively anaerobic and chemo-organotrophic. Chemotaxonomically, members of the genus Solimonas possess Q-8 as the major respiratory quinone, C16 : 0 and C18 : 1ω7c as predominant fatty acids and phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an uncharacterized aminophospholipid as dominant polar lipids; the DNA G+C content is 64.9–68.4 mol%. Phylogenetic evidence, supported by chemotaxonomic and phenotypic data, allowed us to assign strain NAA16T to the genus Solimonas within the novel species Solimonas aquatica sp. nov. (type strain NAA16T  = BCRC 17835T  = LMG 24500T). The reclassification of Sinobacter flavus as Solimonas flava comb. nov. (type strain CW-KD 4T  = DSM 18980T  = KCTC 12881T  = CCTCC AB 206145T) and Singularimonas variicoloris as Solimonas variicoloris comb. nov. (type strain MN28T  = DSM 15731T  = LMG 22844T) is also proposed.
Kroppenstedtia eburnea gen. nov., sp. nov., a thermoactinomycete isolated by environmental screening, and emended description of the family Thermoactinomycetaceae Matsuo et al. 2006 emend. Yassin et al. 2009
Authors: von Jan Mathias , Riegger Nicole , Pötter Gabriele , Schumann Peter , Verbarg Susanne , Spröer Cathrin , Rohde Manfred , Lauer Bettina , Labeda David P. , Klenk Hans-Peter
Published: October 2010

A Gram-positive, spore-forming, aerobic, filamentous bacterium, strain JFMB-ATET, was isolated in 2008 during environmental screening of a plastic surface in grade C in a contract manufacturing organization in southern Germany. The isolate grew at temperatures of 25–50 °C and at pH 5.0–8.5, forming ivory-coloured colonies with sparse white aerial mycelia. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the family Thermoactinomycetaceae, except that the cell-wall peptidoglycan contained ll-diaminopimelic acid, while all previously described members of this family display this diagnostic diamino acid in meso-conformation. The DNA G+C content of the novel strain was 54.6 mol%, the main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, and the major menaquinone was MK-7. The major fatty acids had saturated C14–C16 branched chains. No diagnostic sugars were detected. Based on the chemotaxonomic results and 16S rRNA gene sequence analysis, the isolate is proposed to represent a novel genus and species, Kroppenstedtia eburnea gen. nov. sp. nov. The type strain is JFMB-ATET ( = DSM 45196T  = NRRL B-24804T  = CCUG 59226T).
Propioniciclava tarda gen. nov., sp. nov., isolated from a methanogenic reactor treating waste from cattle farms
Authors: Sugawara Yoshimichi , Ueki Atsuko , Abe Kunihiro , Kaku Nobuo , Watanabe Kazuya , Ueki Katsuji
Published: October 2010

Two facultatively anaerobic bacterial strains, designated WR061Tand WR054, were isolated from rice-straw residue in a methanogenic reactor treating waste from cattle farms in Japan. The two strains were phylogenetically positioned close to one another and had almost the same phenotypic properties. Cells were Gram-reaction-positive, non-motile, non-spore-forming, irregular rods. Cobalamin (vitamin B12) was required for growth. The strains utilized various carbohydrates, including hexoses and disaccharides, and produced acetate and propionate from these carbohydrates. Pentoses and polysaccharides were not utilized. They grew at 20–37 °C (optimum 35 °C) and pH 5.3–8.0 (optimum pH 6.8–7.5). Catalase and nitrate-reducing activities were detected. Aesculin was hydrolysed. The major cellular fatty acids were anteiso-C15 : 0and C15 : 0DMA, the major respiratory quinone was menaquinone MK-9(H4) and the genomic DNA G+C content was 69.3–69.5 mol%. The diagnostic diamino acid in the peptidoglycan wasmeso-diaminopimelic acid. Phylogenetic analysis based on 16S rRNA gene sequences placed the strains in the phylumActinobacteria. Both strains were remotely related to the species in the familyPropionibacteriaceaeandPropionibacterium propionicumJCM 5830Twas the most closely related type strain with a sequence similarity of 91.6 %. Based on phylogenetic, physiological and chemotaxonomic analyses, the two novel strains together represent a novel species of a new genus, for which the namePropioniciclava tardagen. nov., sp. nov. is proposed. The type strain is WR061T( = JCM 15804T = DSM 22130T).
Pseudonocardia kunmingensis sp. nov., an actinobacterium isolated from surface-sterilized roots of Artemisia annua L.
Authors: Zhao Guo-Zhen , Li Jie , Huang Hai-Yu , Zhu Wen-Yong , Park Dong-Jin , Kim Chang-Jin , Xu Li-Hua , Li Wen-Jun
Published: October 2010

A Gram-positive, aerobic, actinobacterial strain with rod-shaped spores, designated YIM 63158T, was isolated from the surface-sterilized roots of Artemisia annua L. collected from Yunnan province, south-west China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 63158T belonged to the genus Pseudonocardia. The closest neighbours were ‘Pseudonocardia sichuanensis’ KLBMP 1115 (99.9 % 16S rRNA gene sequence similarity), Pseudonocardia adelaidensis EUM 221T (99.1 %) and Pseudonocardia zijingensis DSM 44774T (98.8 %); sequence similarities to other members of the genus Pseudonocardia ranged from 98.6 to 94.4 %. The chemotaxonomic characteristics, such as the cell-wall diaminopimelic acid, whole-cell sugars, fatty acid components and major menaquinones, suggested that the isolate belonged to the genus Pseudonocardia. The G+C content of the genomic DNA was 73.3 mol%. On the basis of physiological, biochemical and chemotaxonomic data, including low DNA–DNA relatedness between the isolate and other members of the genus Pseudonocardia, it is proposed that strain YIM 63158T represents a novel species in this genus, with the name Pseudonocardia kunmingensis sp. nov. The type strain is YIM 63158T ( = DSM 45301T  = CCTCC AA 208081T).
Rec8-containing cohesin maintains bivalents without turnover during the growing phase of mouse oocytes
Authors: Tachibana-Konwalski Kikuë , Godwin Jonathan , van der Weyden Louise , Champion Lysie , Kudo Nobuaki R. , Adams David J. , Nasmyth Kim
Published: October 2010

During female meiosis, bivalent chromosomes are thought to be held together from birth until ovulation by sister chromatid cohesion mediated by cohesin complexes whose ring structure depends on kleisin subunits, either Rec8 or Scc1. Because cohesion is established at DNA replication in the embryo, its maintenance for such a long time may require cohesin turnover. To address whether Rec8- or Scc1-containing cohesin holds bivalents together and whether it turns over, we created mice whose kleisin subunits can be cleaved by TEV protease. We show by microinjection experiments and confocal live-cell imaging that Rec8 cleavage triggers chiasmata resolution during meiosis I and sister centromere disjunction during meiosis II, while Scc1 cleavage triggers sister chromatid disjunction in the first embryonic mitosis, demonstrating a dramatic transition from Rec8- to Scc1-containing cohesin at fertilization. Crucially, activation of an ectopic Rec8 transgene during the growing phase of Rec8TEV/TEV oocytes does not prevent TEV-mediated bivalent destruction, implying little or no cohesin turnover for ≥2 wk during oocyte growth. We suggest that the inability of oocytes to regenerate cohesion may contribute to age-related meiosis I errors.
Hedonic and nucleus accumbens neural responses to a natural reward are regulated by aversive conditioning
Authors: Roitman Mitchell F. , Wheeler Robert A. , Tiesinga Paul H.E. , Roitman Jamie D. , Carelli Regina M.
Published: October 2010

The nucleus accumbens (NAc) plays a role in hedonic reactivity to taste stimuli. Learning can alter the hedonic valence of a given stimulus, and it remains unclear how the NAc encodes this shift. The present study examined whether the population response of NAc neurons to a taste stimulus is plastic using a conditioned taste aversion (CTA) paradigm. Electrophysiological and electromyographic (EMG) responses to intraoral infusions of a sucrose (0.3 M) solution were made in naïve rats (Day 1). Immediately following the session, half of the rats (n = 6; Paired) received an injection of lithium chloride (0.15 M; i.p.) to induce malaise and establish a CTA while the other half (n = 6; Unpaired) received a saline injection. Days later (Day 5), NAc recordings during infusions of sucrose were again made. Electrophysiological and EMG responses to sucrose did not differ between groups on Day 1. For both groups, the majority of sucrose responsive neurons exhibited a decrease in firing rate (77% and 71% for Paired and Unpaired, respectively). Following conditioning, in Paired rats, EMG responses were indicative of aversion. Moreover, the majority of responsive NAc neurons now exhibited an increase in firing rate (69%). Responses in Unpaired rats were unchanged by the experience. Thus, the NAc differentially encodes the hedonic value of the same stimulus based on learned associations.
Fine Quantitative Trait Loci Mapping of Carbon and Nitrogen Metabolism Enzyme Activities and Seedling Biomass in the Maize IBM Mapping Population
Authors: Zhang Nengyi , Gibon Yves , Gur Amit , Chen Charles , Lepak Nicholas , Höhne Melanie , Zhang Zhiwu , Kroon Dallas , Tschoep Hendrik , Stitt Mark , Buckler Edward
Published: October 2010

Understanding the genetic basis of nitrogen and carbon metabolism will accelerate the development of plant varieties with high yield and improved nitrogen use efficiency. A robotized platform was used to measure the activities of 10 enzymes from carbon and nitrogen metabolism in the maize (Zea mays) intermated B73 × Mo17 mapping population, which provides almost a 4-fold increase in genetic map distance compared with conventional mapping populations. Seedling/juvenile biomass was included to identify its genetic factors and relationships with enzyme activities. All 10 enzymes showed heritable variation in activity. There were strong positive correlations between activities of different enzymes, indicating that they are coregulated. Negative correlations were detected between biomass and the activity of six enzymes. In total, 73 significant quantitative trait loci (QTL) were found that influence the activity of these 10 enzymes and eight QTL that influence biomass. While some QTL were shared by different enzymes or biomass, we critically evaluated the probability that this may be fortuitous. All enzyme activity QTL were in trans to the known genomic locations of structural genes, except for single cis-QTL for nitrate reductase, Glu dehydrogenase, and shikimate dehydrogenase; the low frequency and low additive magnitude compared with trans-QTL indicate that cis-regulation is relatively unimportant versus trans-regulation. Two-gene epistatic interactions were identified for eight enzymes and for biomass, with three epistatic QTL being shared by two other traits; however, epistasis explained on average only 2.8% of the genetic variance. Overall, this study identifies more QTL at a higher resolution than previous studies of genetic variation in metabolism.
TheMedicago truncatulaE3 Ubiquitin Ligase PUB1 Interacts with the LYK3 Symbiotic Receptor and Negatively Regulates Infection and Nodulation
Authors: Mbengue Malick , Camut Sylvie , de Carvalho-Niebel Fernanda , Deslandes Laurent , Froidure Solène , Klaus-Heisen Dörte , Moreau Sandra , Rivas Susana , Timmers Ton , Hervé Christine , Cullimore Julie , Lefebvre Benoit
Published: October 2010

LYK3 is a lysin motif receptor-like kinase of Medicago truncatula, which is essential for the establishment of the nitrogen-fixing, root nodule symbiosis with Sinorhizobium meliloti. LYK3 is a putative receptor of S. meliloti Nod factor signals, but little is known of how it is regulated and how it transduces these symbiotic signals. In a screen for LYK3-interacting proteins, we identified M. truncatula Plant U-box protein 1 (PUB1) as an interactor of the kinase domain. In planta, both proteins are localized and interact in the plasma membrane. In M. truncatula, PUB1 is expressed specifically in symbiotic conditions, is induced by Nod factors, and shows an overlapping expression pattern with LYK3 during nodulation. Biochemical studies show that PUB1 has a U-box–dependent E3 ubiquitin ligase activity and is phosphorylated by the LYK3 kinase domain. Overexpression and RNA interference studies in M. truncatula show that PUB1 is a negative regulator of the LYK3 signaling pathway leading to infection and nodulation and is important for the discrimination of rhizobia strains producing variant Nod factors. The potential role of PUB E3 ubiquitin ligases in controlling plant–microbe interactions and development through interacting with receptor-like kinases is discussed.
A Novel Glucosylation Reaction on Anthocyanins Catalyzed by Acyl-Glucose–Dependent Glucosyltransferase in the Petals of Carnation and Delphinium
Authors: Matsuba Yuki , Sasaki Nobuhiro , Tera Masayuki , Okamura Masachika , Abe Yutaka , Okamoto Emi , Nakamura Haruka , Funabashi Hisakage , Takatsu Makoto , Saito Mikako , Matsuoka Hideaki , Nagasawa Kazuo , Ozeki Yoshihiro
Published: October 2010

Glucosylation of anthocyanin in carnations (Dianthus caryophyllus) and delphiniums (Delphinium grandiflorum) involves novel sugar donors, aromatic acyl-glucoses, in a reaction catalyzed by the enzymes acyl-glucose–dependent anthocyanin 5(7)-O-glucosyltransferase (AA5GT and AA7GT). The AA5GT enzyme was purified from carnation petals, and cDNAs encoding carnation Dc AA5GT and the delphinium homolog Dg AA7GT were isolated. Recombinant Dc AA5GT and Dg AA7GT proteins showed AA5GT and AA7GT activities in vitro. Although expression of Dc AA5GT in developing carnation petals was highest at early stages, AA5GT activity and anthocyanin accumulation continued to increase during later stages. Neither Dc AA5GT expression nor AA5GT activity was observed in the petals of mutant carnations; these petals accumulated anthocyanin lacking the glucosyl moiety at the 5 position. Transient expression of Dc AA5GT in petal cells of mutant carnations is expected to result in the transfer of a glucose moiety to the 5 position of anthocyanin. The amino acid sequences of Dc AA5GT and Dg AA7GT showed high similarity to glycoside hydrolase family 1 proteins, which typically act as β-glycosidases. A phylogenetic analysis of the amino acid sequences suggested that other plant species are likely to have similar acyl-glucose–dependent glucosyltransferases.
A Maize Thiamine Auxotroph Is Defective in Shoot Meristem Maintenance
Authors: Woodward John B. , Abeydeera N. Dinuka , Paul Debamita , Phillips Kimberly , Rapala-Kozik Maria , Freeling Michael , Begley Tadhg P. , Ealick Steven E. , McSteen Paula , Scanlon Michael J.
Published: October 2010

Plant shoots undergo organogenesis throughout their life cycle via the perpetuation of stem cell pools called shoot apical meristems (SAMs). SAM maintenance requires the coordinated equilibrium between stem cell division and differentiation and is regulated by integrated networks of gene expression, hormonal signaling, and metabolite sensing. Here, we show that the maize (Zea mays) mutant bladekiller1-R (blk1-R) is defective in leaf blade development and meristem maintenance and exhibits a progressive reduction in SAM size that results in premature shoot abortion. Molecular markers for stem cell maintenance and organ initiation reveal that both of these meristematic functions are progressively compromised in blk1-R mutants, especially in the inflorescence and floral meristems. Positional cloning of blk1-R identified a predicted missense mutation in a highly conserved amino acid encoded by thiamine biosynthesis2 (thi2). Consistent with chromosome dosage studies suggesting that blk1-R is a null mutation, biochemical analyses confirm that the wild-type THI2 enzyme copurifies with a thiazole precursor to thiamine, whereas the mutant enzyme does not. Heterologous expression studies confirm that THI2 is targeted to chloroplasts. All blk1-R mutant phenotypes are rescued by exogenous thiamine supplementation, suggesting that blk1-R is a thiamine auxotroph. These results provide insight into the role of metabolic cofactors, such as thiamine, during the proliferation of stem and initial cell populations.
RAD5A, RECQ4A, and MUS81 Have Specific Functions in Homologous Recombination and Define Different Pathways of DNA Repair inArabidopsis thaliana
Authors: Mannuss Anja , Dukowic-Schulze Stefanie , Suer Stefanie , Hartung Frank , Pacher Michael , Puchta Holger
Published: October 2010

Complex DNA structures, such as double Holliday junctions and stalled replication forks, arise during DNA replication and DNA repair. Factors processing these intermediates include the endonuclease MUS81, helicases of the RecQ family, and the yeast SNF2 ATPase RAD5 and its Arabidopsis thaliana homolog RAD5A. By testing sensitivity of mutant plants to DNA-damaging agents, we defined the roles of these factors in Arabidopsis. rad5A recq4A and rad5A mus81 double mutants are more sensitive to cross-linking and methylating agents, showing that RAD5A is required for damage-induced DNA repair, independent of MUS81 and RECQ4A. The lethality of the recq4A  mus81 double mutant indicates that MUS81 and RECQ4A also define parallel DNA repair pathways. The recq4A/mus81 lethality is suppressed by blocking homologous recombination (HR) through disruption of RAD51C, showing that RECQ4A and MUS81 are required for processing recombination-induced aberrant intermediates during replication. Thus, plants possess at least three different pathways to process DNA repair intermediates. We also examined HR-mediated double-strand break (DSB) repair using recombination substrates with inducible site-specific DSBs: MUS81 and RECQ4A are required for efficient synthesis-dependent strand annealing (SDSA) but only to a small extent for single-strand annealing (SSA). Interestingly, RAD5A plays a significant role in SDSA but not in SSA.
Fatigue crack detection in metallic plates with non‐linear Lamb wave modulation spectrum
Authors: Guili Gao , Dayong Li , Dequan Shi , Jingwei Dong
Published: October 2010

Purpose

The purpose of this paper is to demonstrate by experiments that non‐linear Lamb wave modulation spectrum (NLWMS) will be a good indicator of fatigue cracks in a metallic plate.

Design/methodology/approach

A system composed of piezoelectric transducers, arbitrary waveform generator, power amplifier, laser vibrometer, digital oscilloscope and computer has been constructed, and using this system, three samples made of 7075‐T6 aluminium alloy plates are studied, respectively. One is with a fatigue crack, one is with a through hole and the other is intact.

Findings

The experimental results show that there are no significant harmonics and sidebands in the intact sample, and there are no modulation frequencies in the drilled‐hole sample. On the contrary, in the cracked sample, there is an abundance of the harmonics and sidebands. Therefore, these new modulation frequency components can be used to indicate the presence of the fatigue crack.

Practical implications

This paper will provide a method for detecting fatigue crack in metallic plates, especially aluminium alloy plates for aerospace applications.

Originality/value

Under the excitation of two different frequency Lamb waves, experiments on 7075‐T6 alloy plates show that new rising modulation frequency components can be used to indicate the presence of the crack. So, the fatigue crack in metallic plates can be detected by NLWMS.
Minimum emission current of indium‐field emission electric propulsion thruster
Authors: Junyi Duan , Xiaoming Kang , Wansheng Zhao
Published: October 2010

Purpose

Field emission electric propulsion (FEEP) thruster is a type of electric propulsion based on space‐proven indium liquid metal ion sources. The lifetime of FEEP thruster limits its application in space. A better method to improve its lifetime is the reduction of emission current. This paper aims to discuss the minimum emission current of operating FEEP thrusters.

Design/methodology/approach

In this work, theoretical models, including fluid‐flow model and ion formation model, are analyzed. Current densities of these models are discussed and the minimum emission current is calculated.

Findings

There are few equilibrium states under low emission current conditions. However, the minimum emission current is the only stable state at which the FEEP thruster can operate.

Research limitations/implications

This analysis is mainly based on the needle indium FEEP, which is compared indirectly with experiments of gallium.

Practical implications

This paper attempts to help designers choose appropriate electric parameters to improve the lifetime of FEEP.

Originality/value

By introducing and analyzing theoretical models, this paper calculates the minimum emission current for stable operation of FEEP.
Longitudinal flight dynamic analysis of an agile UAV
Authors: Maqsood Adnan , Hiong Go Tiauw
Published: October 2010

Purpose

The purpose of this paper is to describe the longitudinal dynamics of a hover‐capable rigid‐winged unmanned aerial vehicles (UAV) under various equilibrium flight conditions. The effects of the variable‐incidence wing in comparison with the fixed in‐incidence wing on the dynamics of UAV are also discussed.

Design/methodology/approach

The aerodynamic modeling of the vehicle covers both pre‐stall and post‐stall regimes using a three‐dimensional vortex lattice method incorporating viscous corrections. The trim states across a velocity spectrum are evaluated using a nonlinear constrained optimization scheme based on sequential quadratic programming. Then linearized dynamic analysis around trim states is carried out in order to compare the characteristics of the conventional platform with the modified platform incorporating variable‐incidence wing.

Findings

It is found that with the variable‐incidence wing, the longitudinal equilibrium flights can be achieved with reduced thrust‐to‐weight ratio demands and lower elevator deflection. However, the use of the variable‐incidence wing changes the dynamic characteristics of the vehicle considerably as indicated through the linear dynamic analysis.

Research limitations/implications

The results presented in this paper are based on linear dynamic analysis about static trim point data. Further analysis taking into account nonlinearity, the unsteady aerodynamic effects and associated cross‐coupling because of asymmetric forces may be needed to reveal the true dynamics of the vehicle under unsteady maneuvers.

Practical implications

The variable‐incidence wing is a useful design feature to reduce the thrust‐to‐weight ratio requirements and to increase elevator control authority, however its effect on the dynamics warrants further investigation.

Originality/value

This is the first paper highlighting the effects of variable‐incidence wing on an agile hover‐capable UAV.
Integrated waypoint path generation and following of an unmanned aerial vehicle
Authors: Lee Sanghyo , Cho Am , Kee Changdon
Published: October 2010

Purpose

The purpose of this paper is to present an efficient method to integrate path generation and following for an unmanned aerial vehicle.

Design/methodology/approach

The shortest path is briefly reviewed using a straight line and a circular arc in a horizontal plane. Based on shortest paths, various path generation algorithms using oriented waypoints are described. Path design unit, which is structured concatenations of line segments and circular arcs, is proposed to represent different paths as one structure. Simple path following controller to follow a straight line and a circle was also implemented with linear‐quadratic regulator control laws. Some flight tests were conducted to verify the efficiency of proposed algorithm.

Findings

Proposed method represents various paths between given waypoints efficiently by a small number of parameters. It does not need a large amount of memory storage and computation time to run in real time on a low‐cost microprocessor.

Originality/value

This paper provides new structured method to generate different paths efficiently including Dubins' set, which makes path following easy by simple switching logic. It needs small computational time to run in real time. The proposed algorithm in this paper could be used as a basis of other applications such as air traffic control and curved landing approach, which require more accurate path control.
The flying laboratory for aeronautics students' education
Authors: Tomczyk Andrzej
Published: October 2010

Purpose

The main targets of the work are analysis and simulation of flying laboratory performance. In particular, synthesis of control system for handling qualities change and evaluation in flight are taken into consideration.

Design/methodology/approach

Modification of handling qualities is obtained by applying indirect flight control system (FBW). The properties of the optimal controller are calculated through the indirect (implicit) model‐following method. In particular, the modified version based on the computer simulations is used.

Findings

Calculation and simulation concern the synthesis of desired handling qualities of the general aviation aircraft PZL‐M20 “Mewa” equipped with indirect (FBW) experimental flight control system. Results of the simulation show that the flying laboratory has the same properties as modeled aircraft, and it is possible to say that handling properties concern attitude orientation of the experimental aircraft is similar to modeled commuter aircraft.

Practical implications

The result of research can be implemented on a project of the flying laboratory based on general aviation aircraft PZL M20 “Mewa”.

Originality/value

The paper presents the practical approach for synthesis of the “Simplified total in flight simulator” performance which can be used for analysis of handling qualities of general aviation aircraft equipped with FBW. Research of this type focuses on military and transport airplanes however, there are no published works in the area of small aircraft so far.
Documentary tools in everyday life: the wedding planner
Authors: McKenzie Pamela J. , Davies Elisabeth
Published: October 2010

Purpose

This paper aims to analyze documentary planning tools for an everyday life project, the wedding, to study how “document work” is constructed in this setting.

Design/methodology/approach

Using Law and Lynch's study of birdwatching guides for novices as a framework, nine commercially‐available wedding planning guides targeted toward the primary planner, almost universally the bride, were analyzed.

Findings

As Law and Lynch found, part of a novice's apprenticeship requires learning how to “see” in ways that are socially organized in and through texts. The paper shows how characteristics of birdwatching guides (naturalistic accountability, a picture theory of representation, and the strategic use of texts) are also evident in wedding planners, and how the very features that make these guides usable also occasion troubles for their users. Wedding planning guides treat the bride as a novice and instruct her in seeing wedding‐related tasks and times as amenable to management. However, planning a wedding requires multiple tasks and times that may be intertwined in ways that make both their representation and their execution highly complex.

Research limitations/implications

The need for both temporal and thematic access highlights more general problems of knowledge organization in presenting a complex planning project in a linear and paper format.

Originality/value

As workplace principles of time and project management are increasingly applied to everyday life, this paper provides a needed case study of the ways that everyday recordkeeping contributes to the novice bride's gendered apprenticeship and embeds her work within broader organizational and ideological systems.