bluuebunny/crossref_metadata_2025 huggingface dataset:
The actin-like MreB cytoskeleton organizes viral DNA replication in bacteria
Authors: Muñoz-Espín Daniel , Daniel Richard , Kawai Yoshikazu , Carballido-López Rut , Castilla-Llorente Virginia , Errington Jeff , Meijer Wilfried J. J. , Salas Margarita
Published: July 2009

Little is known about the organization or proteins involved in membrane-associated replication of prokaryotic genomes. Here we show that the actin-like MreB cytoskeleton of the distantly related bacteria
Escherichia coli
and
Bacillus subtilis
is required for efficient viral DNA replication. Detailed analyses of
B. subtilis
phage ϕ29 showed that the MreB cytoskeleton plays a crucial role in organizing phage DNA replication at the membrane. Thus, phage double-stranded DNA and components of the ϕ29 replication machinery localize in peripheral helix-like structures in a cytoskeleton-dependent way. Importantly, we show that MreB interacts directly with the ϕ29 membrane-protein p16.7, responsible for attaching viral DNA at the cell membrane. Altogether, the results reveal another function for the MreB cytoskeleton and describe a mechanism by which viral DNA replication is organized at the bacterial membrane.
Hepatocyte-specific NEMO deletion promotes NK/NKT cell– and TRAIL-dependent liver damage
Authors: Beraza Naiara , Malato Yann , Sander Leif E. , Al-Masaoudi Malika , Freimuth Julia , Riethmacher Dieter , Gores Gregory J. , Roskams Tania , Liedtke Christian , Trautwein Christian
Published: July 2009

Nuclear factor κB (NF-κB) is one of the main transcription factors involved in regulating apoptosis, inflammation, chronic liver disease, and cancer progression. The IKK complex mediates NF-κB activation and deletion of its regulatory subunit NEMO in hepatocytes (NEMOΔhepa) triggers chronic inflammation and spontaneous hepatocellular carcinoma development. We show that NEMOΔhepa mice were resistant to Fas-mediated apoptosis but hypersensitive to tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) as the result of a strong up-regulation of its receptor DR5 on hepatocytes. Additionally, natural killer (NK) cells, the main source of TRAIL, were activated in NEMOΔhepa livers. Interestingly, depletion of the NK1.1+ cells promoted a significant reduction of liver inflammation and an improvement of liver histology in NEMOΔhepa mice. Furthermore, hepatocyte-specific NEMO deletion strongly sensitized the liver to concanavalin A (ConA)–mediated injury. The critical role of the NK cell/TRAIL axis in NEMOΔhepa livers during ConA hepatitis was further confirmed by selective NK cell depletion and adoptive transfer of TRAIL-deficient−/− mononuclear cells. Our results uncover an essential mechanism of NEMO-mediated protection of the liver by preventing NK cell tissue damage via TRAIL/DR5 signaling. As this mechanism is important in human liver diseases, NEMOΔhepa mice are an interesting tool to give insight into liver pathophysiology and to develop future therapeutic strategies.
Nine lives: plasticity among T helper cell subsets
Authors: Locksley Richard M.
Published: July 2009

The division of labor among two types of T helper (Th) subsets, first described over 20 yr ago, has been buffeted by the discovery of new subsets and new cytokines that can be coaxed out of T cells with increasing disregard for the subset of origin. Although Th17 cells and regulatory T (T reg) cells are widely accepted subsets, and others are being proposed, their plasticity is difficult to reconcile with the definitions of Th subsets as put forth in the initial description of Th1 and Th2 cells. A deeper molecular context will be required to reconcile the ever-increasing complexity of effector T cells.
Vicious circle: systemic autoreactivity in Ro52/TRIM21-deficient mice
Authors: Bolland Silvia , Garcia-Sastre Adolfo
Published: July 2009

Dysregulated innate responses, particularly excessive activation of interferon (IFN) pathways, have been implicated in the development of autoimmune pathologies. Autoreactivity frequently targets IFN-inducible genes such as the Ro autoantigens, which ubiquitinate and inhibit interferon regulatory factors (IRFs). A new study validates the role of these common autoantigens in preventing autoimmunity. The findings reveal that injury-induced systemic autoimmune disease is exacerbated in the absence of Ro52/Trim21 and is driven by the IL-23–Th17 pathway.
Closed-Hub Systems with Protected Connections and the Reduction of Risk of Catheter-Related Bloodstream Infection in Pediatric Patients Receiving Intravenous Prostanoid Therapy for Pulmonary Hypertension
Authors: Ivy D. Dunbar , Calderbank Michelle , Wagner Brandie D. , Dolan Susan , Nyquist Ann-Christine , Wade Michael , Nickels William M. , Doran Aimee K.
Published: July 2009

Background.

Intravenous prostanoids (epoprostenol and treprostinil) are effective therapies for pulmonary arterial hypertension but carry a risk of catheter-related bloodstream infection (CR-BSI). Prevention of CR-BSI during long-term use of indwelling central venous catheters is important.

Objective.

To evaluate whether using a closed-hub system and waterproofing catheter hub connections reduces the rate of CR-BSI per 1,000 catheter-days.

Design.

Single-center open observational study (January 2003-December 2008).

Patients.

Pediatric patients with pulmonary arterial hypertension who received intravenous prostanoids.

Methods.

In July 2007, CR-BSI preventive measures were implemented, including the use of a closed-hub system and the waterproofing of catheter hub connections during showering. Rates of CR-BSI before and after implementing preventive measures were compared with respect to medication administered and type of bacterial infection.

Results.

Fifty patients received intravenous prostanoid therapy for a total of 41,840 catheter-days. The rate of CR-BSI during the study period was 0.51 infections per 1,000 catheter-days for epoprostenol and 1.38 infections per 1,000 catheter-days for treprostinil, which differed significantly (P < .01 ). CR-BSIs caused by gram-negative pathogens occurred more frequently with treprostinil than with epoprostenol (0.91 infections per 1,000 catheter-days vs 0.08 infections per 1,000 catheter-days; P <.01). Patients treated with treprostinil after the implemented changes had a significant decrease in CR-BSI rate (1.95 infections per 1,000 catheter-days vs 0.19 infections per 1,000 catheter-days; P <.01).

Conclusion.

The closed-hub system and the maintenance of dry catheter hub connections significantly reduced the incidence of CR-BSI (particularly infections caused by gram-negative pathogens) in patients receiving intravenous treprostinil.
Active Surveillance for Methicillin-Resistant Staphylococcus aureus in the Neonatal Intensive Care Unit
Authors: Sarda Vanessa , Molloy Anne , Kadkol Shirahi , Janda William M. , Hershow Ronald , McGuinn Marcella
Published: July 2009

Background.

We describe our experience using a real-time polymerase chain reaction (PCR) assay for methicillin-resistant Staphylococcus aureus (MRSA) during a period of active surveillance in the neonatal intensive care unit (NICU) from March 2007 until November 2007.

Objective.

TO compare PCR with bacterial culture methods and find the screening algorithm that most successfully ensures appropriate isolation of colonized patients.

Methods.

Patients in the NICU were screened for MRSA on admission and weekly thereafter until discharge. Healthcare workers (HCWs) were also screened as part of an outbreak investigation. A total of 599 individuals were screened for MRSA with both a PCR assay and selective bacterial culture. Strain typing was performed on all MRSA isolates to determine clonal relatedness.

Results.

Twenty-one of 435 infants (4.8%) screened positive for MRSA with the PCR assay. Only 11 patients (52.4%) had concomitant bacterial cultures positive for MRSA. Compared to bacterial culture, the PCR assay had a sensitivity of 100% and a specificity of 97.6%, with a positive predictive value (PPV) of 52.4%. Infants that tested positive for MRSA by both culture and PCR were more likely to have a positive PCR assay result when retested than were those who tested positive by PCR alone (80% vs 20%; P = .02). Strain typing of MRSA isolates identified a common clone in only 2 colonized infants.

Conclusion.

Our data show that, in our neonatal population, the reproducibility of PCR assay results for culture-negative patients was low compared with the reproducibility of results for culture-positive Patients. Furthermore, the low PPV suggests that for nearly half of individuals who were PCR-positive, the result was falsely positive, which argues against the use of PCR assays alone for MRSA screening in the NICU.
Selective Alignment of D2 Induced by Two Ultrashort Laser Pulses
Authors: Yang Zeng-qiang , Guo Zhi-rong , Ge Gui-xian
Published: July 2009

The dynamics of molecular rotational wave packets of D2 induced by ultrashort laser pulses was investigated numerically by solving the time-dependent Schrodinger equation. Results show that an ultrashort pulse can manipulate a coherent rotational wave packet of D2 selectively. In the calculation, a first laser pulse was used to create a coherent rotational wave packet from an initial thermal ensemble of D2 at the temperature of 300 K. The second laser pulse was used to manipulate the rotational wave packet selectively around the first quarter and the three quarters revival. The alignment parameter and its Fourier transform amplitude both illustrate that the relative populations of even and odd rotational states in the final rotational wave packet of D2 can be manipulated by precisely selecting the time delay between the first and the second ultrashort pulse.
Theoretical Study of the CCl Bond Dissociation Enthalpy and Electronic Structure of Substituted Chlorobenzene Compounds
Authors: Zhang Rui-zhou , Li Xiao-hong , Zhang Xian-zhou
Published: July 2009

Quantum chemical calculations were used to estimate the bond dissociation energies (BDEs) for 13 substituted chlorobenzene compounds. These compounds were studied by the hybrid density functional theory (B3LYP, B3PW91, B3P86) methods together with 631G** and 6311G** basis sets. The results show that B3P86/6311G** method is the best method to compute the reliable BDEs for substituted chlorobenzene compounds which contain the CCl bond. It is found that the CCl BDE depends strongly on the computational method and the basis sets used. Substituent effect on the CCl BDE of substituted chlorobenzene compounds is further discussed. It is noted that the effects of substitution on the CCl BDE of substituted chlorobenzene compounds are very insignificant. The energy gaps between the HOMO and LUMO of studied compounds are also investigated and from this data we estimate the relative thermal stability ordering of substituted chlorobenzene compounds.
Influences of Li Intercalation on the Electronic Structures of O2p and V3d Orbitals in -V2O5
Authors: Li Zhi-yang , Lin Xiu-zhu , Wu Qi-hui
Published: July 2009

The influence of Li intercalation on the electronic structures of oxygen and vanadium ions in -V2O5 was investigated using first-principles calculations based on the density functional theory with local density approximation. Two different intercalation sites for Li in the V2O5 lattices were considered. The calculation results demonstrate that intercalated Li ions at different sites show different effects on the electronic structures of O2p and V3d orbitals. But in both cases Li intercalation will weaken the V = O1 bonding and cause the split-off in V3d valence band to narrow or even disappear and simultaneously broaden the O2p conduction band. Further, the average electron transfer number from per intercalated Li2s to V3d orbitals is determined to total be about 0.52.
Repeat Sequences and Base Correlations in Human Y Chromosome Palindromes
Authors: Jin Neng-zhi , Liu Zi-xian , Qi Yan-jiao , Qiu Wen-yuan
Published: July 2009

On the basis of information theory and statistical methods, we use mutual information, n-tuple entropy and conditional entropy, combined with biological characteristics, to analyze the long range correlation and short range correlation in human Y chromosome palindromes. The magnitude distribution of the long range correlation which can be reflected by the mutual information is P5>P5a>P5b (P5a and P5b are the sequences that replace solely Alu repeats and all interspersed repeats with random uncorrelated sequences in human Y chromosome palindrome 5, respectively); and the magnitude distribution of the short range correlation which can be reflected by the n-tuple entropy and the conditional entropy is P5>P5a>P5b>random uncorrelated sequence. In other words, when the Alu repeats and all interspersed repeats replace with random uncorrelated sequence, the long range and short range correlation decrease gradually. However, the random uncorrelated sequence has no correlation. This research indicates that more repeat sequences result in stronger correlation between bases in human Y chromosome. The analyses may be helpful to understand the special structures of human Y chromosome palindromes profoundly.
3D-QSAR Study of 7,8-Dialkyl-1,3-diaminopyrrolo-[3,2-f] Quinazolines with Anticancer Activity as DHFR Inhibitors
Authors: Chen Jin-can , Chen Lan-mei , Liao Si-yan , Qian Li , Zheng Kang-cheng
Published: July 2009

A three-dimensional quantitative structure-activity relationship (3D-QSAR) study of a series of 7,8-dialkyl-1,3-diaminopyrrolo-[3,2-f] quinazolines with anticancer activity as dihydrofolate reductase (DHFR) inhibitors was carried out by using the comparative molecular field analysis (CoMFA), on the basis of our reported 2D-QSAR of these compounds. The established 3D-QSAR model has good quality of statistics and good prediction ability; the non cross-validation correlation coefficient and the cross-validation value of this model are 0.993 and 0.619, respectively, the F value is 193.4, and the standard deviation SD is 0.208. This model indicates that the steric field factor plays a much more important role than the electrostatic one, in satisfying agreement with the published 2D-QSAR model. However, the 3D-QSAR model offers visual images of the steric field and the electrostatic field. The 3D-QSAR study further suggests the following: to improve the activity, the substituent R should be selected to be a group with an adaptive bulk like Et or i-Pr, and the substituent R should be selected to be a larger alkyl. In particular, based on our present 3D-QSAR as well as the published 2D-QSAR, the experimentally-proposed hydrophobic binding mechanism on the receptor-binding site of the DHFR can be further explained in theory. Therefore, the QSAR studies help to further understand the hydrophobic binding" action mechanism of this kind of compounds, and to direct the molecular design of new drugs with higher activity.
Effect of Hydrogen Addition on Methane HCCI Engine Ignition Timing and Emissions Using a Multi-zone Model
Authors: Wang Zi-han , Wang Chun-mei , Tang Hua-xin , Zuo Cheng-ji , Xu Hong-ming
Published: July 2009

Ignition timing control is of great importance in homogeneous charge compression ignition engines. The effect of hydrogen addition on methane combustion was investigated using a CHEMKIN multi-zone model. Results show that hydrogen addition advances ignition timing and enhances peak pressure and temperature. A brief analysis of chemical kinetics of methane blending hydrogen is also performed in order to investigate the scope of its application, and the analysis suggests that OH radical plays an important role in the oxidation. Hydrogen addition increases NOx while decreasing HC and CO emissions. Exhaust gas recirculation (EGR) also advances ignition timing; however, its effects on emissions are generally the opposite. By adjusting the hydrogen addition and EGR rate, the ignition timing can be regulated with a low emission level. Investigation into zones suggests that NOx is mostly formed in core zones while HC and CO mostly originate in the crevice and the quench layer.
CS Activation of CS2 by Nb+ in Gas Phase
Authors: Song Xiao-li , Gao Li-guo
Published: July 2009

The reaction of Nb+ with CS2, producing cationic transition-metal sulfide and CS, was taken as a representative example to elucidate the overall mechanism of reactions of second-row early transition metal ions with CS2. The reactions in both triplet and quintet state were studied by using the UB3LYP density functional method with the Stuttgart pseudo potentials and corresponding basis sets for Nb+ and the standard 6311+G(2d) basis sets for C and S. The geometries for reactants, the transition states, and the products were completely optimized. All the transition states were verified by vibrational analysis and intrinsic reaction coordinate calculations. The results show that the reaction mechanism between niobium ion and CS2 is an insertion-elimination mechanism. Intersystem crossing may occur in the reaction Nb+ with CS2 and a minimum energy crossing point was found.
Molecular Dynamics Simulations for Melting Temperatures of SrF2 and BaF2
Authors: Huang Xiao-yu , Cheng Xin-lu , Fan Chao-lei , Chen Qiong , Yuan Xiao-li
Published: July 2009

The shell-model molecular dynamics method was applied to simulate the melting temperatures of SrF2 and BaF2 at elevated temperatures and high pressures. The same method was used to calculate the equations of state for SrF2 and BaF2 over the pressure range of 0.1 MPa-3 GPa and 0.1 MPa-7 GPa. Compared with previous results for equations of state, the maximum errors are 0.3% and 2.2%, respectively. Considering the pre-melting in the fluorite-type crystals, we made the necessary corrections for the simulated melting temperatures of SrF2 and BaF2. Consequently, the melting temperatures of SrF2 and BaF2 were obtained for high pressures. The melting temperatures of SrF2 and BaF2 that were obtained by the simulation are in good agreement with available experimental data.
The Initial Reactions of H3PO4 and NaH2PO4 Supported on Silica: A Joint Experimental and Theoretical Study
Authors: Zhang Zhi-qiang , Qu Yi-xin , Wang Shui , Wang Ji-dong
Published: July 2009

A combination of X-ray powder diffraction, thermogravimetric analysis, diffuse reflection infrared Fourier transform, and 31P magic-angle spinning nuclear magnetic resonance techniques with density function computation was used to elucidate the products and mechanism of the reactions among silica, H3PO4, and NaH2PO4 during the preparation of silica supported H3PO4 and NaH2PO4 catalysts. The spectral test results indicate that besides polyphosphoric acid, silicon phosphates on silica supported H3PO4 are also formed. On silica supported NaH2PO4 only sodium polyphosphates are present. Density functional theory (DFT) simulations indicate that in the initial stage, reaction of H3PO4 with silanol groups on the silica support is more favorable than that between H3PO4 itself. In contrast, dimerization and trimerization of NaH2PO4 are predicted to be the predominant initial reactions for the silica supported NaH2PO4 catalyst.
Research on Raman-scattering and Fabrication of Multilayer Thin Film with Different Structures and Components Based on Pt/Ti/Si3N4/SiO2/Si Substrate
Authors: Tan Qiu-lin , Zhang Wen-dong , Xue Chen-yang , Liu Jun , Li Jun-hong , Xiong Ji-jun
Published: July 2009

Using the same conditions and various starting materials, such as lead acetate trihydrate, tetrabulyl titanate, zirconium n-butoxide, and acetylacetone, two kinds of solid precursors, lead zirconate titanate (PZT, Zr/Ti = 15/85) and lead titanate (PT), were fabricated. With three different combinations, namely, PZT, PT/PZT-PZT/PT, and PT/PZT/-/PZT/PT, three multilayer thin films were deposited on three Pt-Ti-Si3N4-SiO2-Si substrates by a modified sol-gel process. The fabrication process of the thin films is discussed in detail. We found that there is a large built-in stress in the thin film, which can be diminished by annealing at 600 C, when the gel is turned into solid material through drying and sintering. The Raman scattering spectra of the films with different compositions and structures were investigated. With the help of X-ray diffraction (XRD) analyzer and Raman scattering spectra analyzer, it was found that the thin films with the PT/PZT-PZT/PT structure have reasonable crystallinity and less residual stress. XRD testing shows that the diffraction pattern of the multilayer film results from the superimposition of the PZT and PT patterns. This leads to the conclusion that the PT/PZT-PZT/PT multilayer thin film has a promising future in pyroelectric infrared detectors with high performance.
Testing children for inherited thrombophilia: more questions than answers
Authors: Raffini Leslie , Thornburg Courtney
Published: July 2009

Thrombotic events in children have become an increasingly common problem, particularly in paediatric tertiary care hospitals. The prevalence of inherited thrombophilia in children who develop thrombosis varies substantially depending on the population. Children who develop thrombosis, as well as those who have not but have a positive family history, are frequently tested for inherited thrombophilia. The clinical utility of performing such tests has been questioned, in both adults and children. This review will examine the practise of testing for inherited thrombophilia in children, focusing on the rationale for testing and highlighting areas in which more evidence is needed prior to making strong recommendations. Future studies, many of which are currently being performed or proposed, are necessary to address many of the unanswered questions.
Evaluation of glycaemic status in young people with clinical insulin resistance; fasting glucose, fasting insulin or an oral glucose tolerance test?
Authors: Garnett Sarah P. , Srinivasan Shubha , Birt Stewart G. , Ambler Geoffrey R. , Lawrie Elizabeth A. , Cowell Chris T. , Craig Maria E.
Published: July 2009

Objective  It is important to identify young people with prediabetes for early intervention. However, it is unclear how to best screen overweight and obese young people for prediabetes. The objective of this study was to compare fasting indices with an oral glucose tolerance test (OGTT) in diagnosing prediabetes.

Design  Retrospective review.

Patients  A total of 224 young people, aged 12·0 years (range: 3·2–17·3 years), with clinical features of insulin resistance, who had an OGTT between 2000 and 2007 at a tertiary children’s hospital, Sydney, Australia.

Measurements  Oral glucose tolerance test.

Results  A total of 168 (75%) participants had normal glucose tolerance, 45 (20%) had prediabetes and 11 (5%) had type 2 diabetes; 29 of those with prediabetes and 10 with type 2 diabetes were identified by fasting glucose criteria alone. Young people with normal fasting glucose and fasting insulin ≤180 pmol/l had lower insulin resistance (homeostasis model assessment median 1·9 vs. 4·2, P < 0·001), higher insulin sensitivity index (2·4 vs. 1·0, P < 0·001) and a lower early insulin response (insulinogenic index 2·5 vs. 4·1, P < 0·001) compared to those with normal fasting glucose and higher fasting insulin levels. If a fasting insulin cut point (≤180 pmol/l) was used in addition to fasting glucose to determine the need for an OGTT, 114 (68%) young people with normal glucose tolerance would have avoided the test. By contrast, the diagnosis of impaired glucose tolerance, identified by an OGTT, would have been missed in three children.

Conclusion  Fasting glucose and insulin levels should be measured in young people with insulin resistance before undertaking a time‐ and resource‐intensive OGTT.
Temporal and shrub adaptation effect on soil microbial functional diversity in a desert system
Authors: Saul‐Tcherkas V. , Steinberger Y.
Published: July 2009

The Negev Desert is characterized by spatial and temporal patterns of resource distribution, in which soil biota are considered to be among the most sensitive biological characteristics, easily influenced by changes related to soil and abiotic factors. Soil water availability and organic matter are among the most important factors, acting as triggers that determine the length of the period of activity. The main source of organic matter in this xeric environment is input from annual and perennial shrubs. In order to persist and propagate in this xeric environment, the plants have developed different ecophysiological adaptations (e.g. the excretion of salt (Reaumuria negevensis) and chemical compounds (Artemisia sieberi) via the leaves). We found that the values of soil moisture obtained for soil samples collected in the vicinity of R. negevensis were larger than for samples collected in the vicinity of Noaea mucronata and A. sieberi and in the open area. The maximum values of CO2 evolution, microbial biomass and Shannon index (H′) were obtained for the samples collected from the vicinity of N. mucronata. Therefore, we assume that the vicinity of N. mucronata afforded the best conditions for the soil bacterial community. In the Negev Desert, we also found that water availability and pulses of rain compared with frequent rainfall influenced CO2 evolution, microbial biomass, qCO2 and the Shannon index (H′). The differences in water amount and availability between the two rainy seasons caused larger values in most of the properties during the first four seasons (December 2005–November 2006) compared with the last four seasons (December 2006–November 2007) for most of the samples.
Effects of culture, social presence, and group composition on trust in technology‐supported decision‐making groups
Authors: Lowry Paul Benjamin , Zhang Dongsong , Zhou Lina , Fu Xiaolan
Published: July 2009

This study examines trust in technology‐supported groups from the perspectives of culture, social presence and group composition. Our results demonstrate that, in culturally homogeneous groups, individualism has a negative impact on the level of interpersonal trust; however, in culturally heterogeneous groups consisting of Chinese and U.S. participants, individualism has a positive impact on interpersonal trust among members. There were also significant differences in the level of trust between homogeneous Chinese groups and heterogeneous groups consisting of Chinese and U.S. participants. In addition, the mediating role of communication quality was identified to explain the effect for trust‐of social presence on trust. These findings have important implications on building and communication in global technology‐supported decision‐making groups.
Spatio‐temporal structure of multi‐storied, multi‐aged interior Douglas fir (Pseudotsuga menziesiivar.glauca) stands
Authors: LeMay Valerie , Pommerening Arne , Marshall Peter
Published: July 2009

1. We used replicated, repeated‐measures data to examine the spatio‐temporal structure of multi‐storied, multi‐aged interior Douglas fir (Pseudotsuga menziesiivarglauca(Mirb.) Franco) stands growing on dry sites under more than 50 years of fire protection. Along with the univariate and bivariate Ripley’sKand related functions, we used a random coefficients mixed model to investigate the variation in these functions over replicates and time.

2. The spatio‐temporal analyses revealed that trees greater than 1.3 m in height were clustered over space, and clustering was more evident for small trees (i.e. diameter at breast height (d.b.h.) ≤ 7.0 cm).

3. Bivariate functions indicated that small trees were spatially aggregated with large trees, indicating higher germination success and early survival near large trees. For these dry sites, moisture is more limiting than light and large trees provide moister microsites.

4. Dead trees were clustered, more commonly smaller in size and aggregated near large trees, indicating competition for moisture.

5. For the 16‐year period of the study, there was very little evidence that the spatio‐temporal patterns changed from a clustered to a more regular arrangement over time, unlike evidence from studies in other forest types.

6. Using the random coefficients mixed model approach, the majority of spatio‐temporal variation was due to differences among replicates, with little variation over time.

7. Under fire protection, interior Douglas fir stands on dry sites might be expected to have lower mortality but any increase in density will be limited by moisture availability. Since interior Douglas fir is moderately shade‐tolerant, this may result in an approach to a steady state of regeneration and death over the long term.

8.Synthesis. Spatio‐temporal analysis using replicated, repeated‐measures data, including a random coeffcieints mixed model approach, gave useful insights into mortality and recruitment in multi‐storied and multi‐aged stands. Similar patterns might be expected in other naturally occurring multi‐storied and multi‐aged stands. The use of replicated, repeated‐measures data rather than chronosequence data allows for the examination of true changes in spatial patterns over time.
Waiting for fungi: the ectomycorrhizal invasion of lowland heathlands
Authors: Collier Fay A. , Bidartondo Martin I.
Published: July 2009

1. In England, the loss of lowland heathland, a habitat of global conservation importance, is primarily due to the invasion of birch and pine. This encroachment has been researched in depth from a plant perspective but little is known about the role of mycorrhizal fungi. In lowland heathlands the resident dwarf shrubs form ericoid mycorrhizas whereas invading trees form ectomycorrhizas. Therefore, tree encroachment into heathlands can be regarded as the replacement of a resident mycorrhizal community by an invading one.

2. This study examined how fungi form mycorrhizas with Betula and Pinus in lowland heathlands. We addressed the question of whether there are mycorrhizal fungi that mediate invasion using a molecular ecology approach to compare the mycorrhizal inoculum potential of soil at three levels of invasion (uninvaded heathland, invaded heathland and woodland) and the fungi forming mycorrhizas on tree seedlings and trees across diverse sites.

3. We show that in lowland heathlands: (i) seedlings have severely limited access to ectomycorrhizal fungi relative to woodlands, (ii) there are few keystone spore‐dispersed ectomycorrhizal fungi that can mediate tree invasion, (iii) tree seedlings can remain non‐mycorrhizal for at least one year when no inoculum is present, even near saplings, and (iv) mycorrhizal seedlings achieve greater biomass than non‐mycorrhizal seedlings. Within uninvaded heathland we detected only Rhizopogon luteolus, Suillus variegatus, S. bovinus (Pinus symbionts) and Laccaria proxima (primarily a Betula symbiont).

4.
Synthesis. Overall, ectomycorrhizal inoculum in lowland heathlands is rare; most tree seedlings growing in heathland soil are not mycorrhizal due to limited spore dispersal, poorly developed spore banks and weak common mycorrhizal networks. These seedlings can persist awaiting mycorrhization to boost their growth.
Mutational analyses of HAMP helices suggest a dynamic bundle model of input–output signalling in chemoreceptors
Authors: Zhou Qin , Ames Peter , Parkinson John S.
Published: July 2009

To test the gearbox model of HAMP signalling in the Escherichia coli serine receptor, Tsr, we generated a series of amino acid replacements at each residue of the AS1 and AS2 helices. The residues most critical for Tsr function defined hydrophobic packing faces consistent with a four‐helix bundle. Suppression patterns of helix lesions conformed to the predicted packing layers in the bundle. Although the properties and patterns of most AS1 and AS2 lesions were consistent with both proposed gearbox structures, some mutational features specifically indicate the functional importance of an x‐da bundle over an alternative a‐d bundle. These genetic data suggest that HAMP signalling could simply involve changes in the stability of its x‐da bundle. We propose that Tsr HAMP controls output signals by modulating destabilizing phase clashes between the AS2 helices and the adjoining kinase control helices. Our model further proposes that chemoeffectors regulate HAMP bundle stability through a control cable connection between the transmembrane segments and AS1 helices. Attractant stimuli, which cause inward piston displacements in chemoreceptors, should reduce cable tension, thereby stabilizing the HAMP bundle. This study shows how transmembrane signalling and HAMP input–output control could occur without the helix rotations central to the gearbox model.
Contributions of disease resistance and escape to the control of septoria tritici blotch of wheat
Authors: Arraiano L. S. , Balaam N. , Fenwick P. M. , Chapman C. , Feuerhelm D. , Howell P. , Smith S. J. , Widdowson J. P. , Brown J. K. M.
Published: July 2009

The contributions of disease escape and disease resistance to the responses of wheat to septoria tritici leaf blotch (STB) were analysed in a set of 226 lines, including modern cultivars, breeding lines and their progenitors dating back to the origin of scientific wheat breeding. Field trials were located in the important wheat‐growing region of eastern England and were subject to natural infection by Mycosphaerella graminicola. STB scores were related to disease‐escape traits, notably height, leaf spacing, leaf morphology and heading date, and to the presence of known Stb resistance genes and isolate‐specific resistances. The Stb6 resistance gene was associated with a reduction of 19% in the level of STB in the complete set of 226 lines and with a 33% reduction in a subset of 139 lines of semidwarf stature. Greater plant height was strongly associated with reduced STB in the full set of lines, but only weakly in the semidwarf lines. Shorter leaf length was also associated with reduced STB, but, in contrast to earlier reports, lines with more prostrate leaves had more STB on average, probably because they tended to have longer leaves. Several lines, notably cvs Pastiche and Exsept, had low mean levels of STB which could not be explained by either escape traits or specific resistance genes, implying that they have unknown genes for partial resistance to STB.
Comprehensive mutational analysis of BRCA1/BRCA2 for Korean breast cancer patients: evidence of a founder mutation
Authors: Seong M‐W , Cho SI , Noh D‐Y , Han W , Kim S‐W , Park C‐M , Park H‐W , Kim SY , Kim JY , Park SS
Published: July 2009

The BRCA1 and BRCA2 genes are the strongest susceptibility genes identified for breast cancer worldwide. However, BRCA1/BRCA2 have been incompletely investigated due to their large size and the genomic rearrangements that occasionally occur within them. Here we performed a comprehensive mutational analysis for BRCA1/BRCA2 in 206 Korean patients with breast cancer.

We analyzed all exons and flanking regions of BRCA1/BRCA2 by direct sequencing and screened deletions or duplications involving BRCA1/BRCA2 by multiplex ligation‐dependent probe amplification. We reconstructed haplotypes using intragenic single nucleotide polymorphisms (SNPs) to investigate the possibility of a founder effect among recurrent mutations. In our series, 38 patients (18.4%) had one or more BRCA1/BRCA2 mutations including 10 novel ones. Three additional patients carried novel distinct unclassified variants with potentially harmful effects. No large deletions or duplications involving BRCA1/BRCA2 were identified in our series. Haplotype analyses and allele separation suggested that the most frequent mutation in Koreans, BRCA2:c.7480C>T, might have originated from a common ancestor. BRCA1/BRCA2 mutations were more frequent in a group with family history, bilateral cancer or multiple site cancer than in a group without the risk factors described or an unknown risk group. In contrast, mutation frequencies in the early‐onset cancer group were not higher than in the unknown risk group.

Our results will be helpful to understand the mutation spectrum in BRCA1/BRCA2 genes and establish a genetic screening strategy. In addition, this study suggests the possibility of the first true founder mutation of BRCA1/BRCA2 identified in the Korean population.
Higher tacrolimus trough levels on days 2–5 post‐renal transplant are associated with reduced rates of acute rejection
Authors: O’Seaghdha C.M. , McQuillan R. , Moran A.M. , Lavin P. , Dorman A. , O’Kelly P. , Mohan D.M. , Little P. , Hickey D.P. , Conlon P.J.
Published: July 2009

Abstract:  We analyzed the association between whole‐blood trough tacrolimus (TAC) levels in the first days post‐kidney transplant and acute cellular rejection (ACR) rates. Four hundred and sixty‐four consecutive, deceased‐donor kidney transplant recipients were included. All were treated with a combination of TAC, mycophenolate mofetil and prednisolone. Patients were analyzed in four groups based on quartiles of the mean TAC on days 2 and 5 post‐transplant: Group 1: median TAC 11 ng/mL (n = 122, range 2–13.5 ng/mL), Group 2: median 17 ng/mL (n = 123, range 14–20 ng/mL), Group 3: median 24 ng/mL (n = 108, range 20.5–27 ng/mL) and Group 4: median 33.5 ng/mL (n = 116, range 27.5–77.5 ng/mL). A graded reduction in the rates of ACR was observed for each incremental days 2–5 TAC. The one‐yr ACR rate was 24.03% (95% CI 17.26–32.88), 22.20% (95% CI 15.78–30.70), 13.41% (95% CI 8.15–21.63) and 8.69% (95% CI 4.77–15.55) for Groups 1–4, respectively (p = 0.003). This study suggests that higher early TACs are associated with reduced rates of ACR at one yr.
NR2B subunit‐dependent long‐term potentiation enhancement in the rat cortical auditory system in vivo following masking of patterned auditory input by white noise exposure during early postnatal life
Authors: Hogsden Jennifer L. , Dringenberg Hans C.
Published: July 2009

The composition of N‐methyl‐d‐aspartate (NMDA) receptor subunits influences the degree of synaptic plasticity expressed during development and into adulthood. Here, we show that theta‐burst stimulation of the medial geniculate nucleus reliably induced NMDA receptor‐dependent long‐term potentiation (LTP) of field postsynaptic potentials recorded in the primary auditory cortex (A1) of urethane‐anesthetized rats. Furthermore, substantially greater levels of LTP were elicited in juvenile animals (30–37 days old; ∼55% maximal potentiation) than in adult animals (∼30% potentiation). Masking patterned sound via continuous white noise exposure during early postnatal life (from postnatal day 5 to postnatal day 50–60) resulted in enhanced, juvenile‐like levels of LTP (∼70% maximal potentiation) relative to age‐matched controls reared in unaltered acoustic environments (∼30%). Rats reared in white noise and then placed in unaltered acoustic environments for 40–50 days showed levels of LTP comparable to those of adult controls, indicating that white noise rearing results in a form of developmental arrest that can be overcome by subsequent patterned sound exposure. We explored the mechanisms mediating white noise‐induced plasticity enhancements by local NR2B subunit antagonist application in A1. NR2B subunit antagonists (Ro 25‐6981 or ifenprodil) completely reversed white noise‐induced LTP enhancement at concentrations that did not affect LTP in adult or age‐matched controls. We conclude that white noise exposure during early postnatal life results in the maintenance of juvenile‐like, higher levels of plasticity in A1, an effect that appears to be critically dependent on NR2B subunit activation.
In the ear of the beholder: neural correlates of adaptation to voice gender
Authors: Zäske Romi , Schweinberger Stefan R. , Kaufmann Jürgen M. , Kawahara Hideki
Published: July 2009

While high‐level adaptation to faces has been extensively investigated, research on behavioural and neural correlates of auditory adaptation to paralinguistic social information in voices has been largely neglected. Here we replicate novel findings that adaptation to voice gender causes systematic contrastive aftereffects such that repeated exposure to female voice adaptors causes a subsequent test voice to be perceived as more male (and vice versa), even minutes after adaptation [S.R. Schweinberger et al., (2008), Current Biology, 18, 684–688). In addition, we recorded event‐related potentials to test‐voices morphed along a gender continuum. An attenuation in frontocentral N1–P2 amplitudes was seen when a test voice was preceded by gender‐congruent voice adaptors. Additionally, similar amplitude attenuations were seen in a late parietal positive component (P3, 300–700 ms). These findings suggest that contrastive coding of voice gender takes place within the first few hundred milliseconds from voice onset, and is implemented by neurons in auditory areas that are specialised for detecting male and female voice quality.
Tonically active neurons in the striatum differentiate between delivery and omission of expected reward in a probabilistic task context
Authors: Apicella Paul , Deffains Marc , Ravel Sabrina , Legallet Eric
Published: July 2009

Tonically active neurons (TANs) in the primate striatum are responsive to rewarding stimuli and they are thought to be involved in the storage of stimulus–reward associations or habits. However, it is unclear whether these neurons may signal the difference between the prediction of reward and its actual outcome as a possible neuronal correlate of reward prediction errors at the striatal level. To address this question, we studied the activity of TANs from three monkeys trained in a classical conditioning task in which a liquid reward was preceded by a visual stimulus and reward probability was systematically varied between blocks of trials. The monkeys’ ability to discriminate the conditions according to probability was assessed by monitoring their mouth movements during the stimulus–reward interval. We found that the typical TAN pause responses to the delivery of reward were markedly enhanced as the probability of reward decreased, whereas responses to the predictive stimulus were somewhat stronger for high reward probability. In addition, TAN responses to the omission of reward consisted of either decreases or increases in activity that became stronger with increasing reward probability. It therefore appears that one group of neurons differentially responded to reward delivery and reward omission with changes in activity into opposite directions, while another group responded in the same direction. These data indicate that only a subset of TANs could detect the extent to which reward occurs differently than predicted, thus contributing to the encoding of positive and negative reward prediction errors that is relevant to reinforcement learning.
Subcutaneous and visceral adipose tissue: structural and functional differences
Authors: Ibrahim M. Mohsen
Published: July 2009

Obesity is a heterogeneous disorder. Obese individuals vary in their body fat distribution, their metabolic profile and degree of associated cardiovascular and metabolic risk. Abdominal obesity carries greater risk of developing diabetes and future cardiovascular events than peripheral or gluteofemoral obesity. There are differences between adipose tissue present in subcutaneous areas (SCAT) and visceral adipose tissue (VAT) present in the abdominal cavity. These include anatomical, cellular, molecular, physiological, clinical and prognostic differences. Anatomically, VAT is present mainly in the mesentery and omentum, and drains directly through the portal circulaion to the liver. VAT compared with SCAT is more cellular, vascular, innervated and contains a larger number of inflammatory and immune cells, lesser preadipocyte differentiating capacity and a greater percentage of large adipocytes. There are more glucocorticoid and androgen receptors in VAT than in SCAT. VAT adipocytes are more metabolically active, more sensitive to lipolysis and more insulin‐resistant than SCAT adipocytes. VAT has a greater capacity to generate free fatty acids and to uptake glucose than SCAT and is more sensitive to adrenergic stimulation, while SCAT is more avid in absorption of circulating free fatty acids and triglycerides. VAT carries a greater prediction of mortality than SCAT.
Prevalence of obesity in Thailand
Authors: Aekplakorn W. , Mo‐suwan L.
Published: July 2009

The prevalence of obesity in Thailand has been doubled in the past two decades. Data from three consecutive National Health examination surveys (NHES) have shown a secular trend, as the prevalence of obesity with body mass index ≥25 kg m−2 in adults increased from 13.0% in men and 23.2% in women in 1991 to 18.6% and 29.5% in 1997 and 22.4% and 34.3% in 2004 respectively. Obesity prevalence in children, using weight for height criteria, increased from 5.8% in 1997 to 7.9% in 2001 for the 2–5‐year‐olds and from 5.8% to 6.7% for the 6–12‐year‐olds. The data also show disproportionate increases of obesity in the rural area, which indicates the problem no longer restricts to the higher socioeconomic group.
On the Confusion Between Ideal and Non-Ideal in Recent Debates on Global Justice
Authors: Ypi Lea
Published: July 2009

This article assesses two contending global theories of justice (cosmopolitanism and statism) in light of the role that ideal and non-ideal considerations should play in political theory. It starts with a distinction between ideal and non-ideal and it proceeds to show how both statists and cosmopolitans are ideal when non-ideal considerations should prevail and how both are non-ideal when ideal theorising is required. This view is assessed with reference to two issues on which statists and cosmopolitans appear particularly divided: the relevance of states and the principles of global justice. With regard to the former, the article shows that the discussion on states is ideal (discussing the place of special associative relations in normative justifications of distributive equality) when it should be non-ideal (emphasising the role of states as the most relevant agents of justice in real-world circumstances). On the second issue, it illustrates how the discussion on principles is non-ideal (limited to assessing the consequences of global poverty in unfavourable conditions) when it should be ideal (investigating the grounds of injustice at the appropriately fundamental level). The article concludes by sketching an alternative analysis of global justice which is able to accommodate some statist and cosmopolitan concerns but which avoids the criticisms that each theory usually attracts.
Connections From Kafka
Authors: Proulx Travis , Heine Steven J.
Published: July 2009

In the current studies, we tested the prediction that learning of novel patterns of association would be enhanced in response to unrelated meaning threats. This prediction derives from the meaning-maintenance model, which hypothesizes that meaning-maintenance efforts may recruit patterns of association unrelated to the original meaning threat. Compared with participants in control conditions, participants exposed to either of two unrelated meaning threats (i.e., reading an absurd short story by Franz Kafka or arguing against one's own self-unity) demonstrated both a heightened motivation to perceive the presence of patterns within letter strings and enhanced learning of a novel pattern actually embedded within letter strings (artificial-grammar learning task). These results suggest that the cognitive mechanisms responsible for implicitly learning patterns are enhanced by the presence of a meaning threat.