bluuebunny/crossref_metadata_2025 huggingface dataset:
Occupations, work characteristics and common mental disorder
Authors: Stansfeld S. A. , Pike C. , McManus S. , Harris J. , Bebbington P. , Brugha T. , Hassiotis A. , Jenkins R. , Meltzer H. , Moran P. , Clark C.
Published: August 2012

Background

The present study aimed to assess the prevalence of common mental disorders (CMDs) by occupation in a representative sample of the English adult population. Another aim was to examine whether the increased risk of CMD in some occupations could be explained by adverse work characteristics.

Method

We derived a sample of 3425 working-age respondents from the Adult Psychiatric Morbidity Survey 2007. Occupations were classified by Standard Occupational Classification group, and CMD measured by the Revised Clinical Interview Schedule. Job characteristics were measured by questionnaire, and tested as explanatory factors in associations of occupation and CMD.

Results

After adjusting for age, gender, housing tenure and marital status, caring personal service occupations had the greatest risk of CMD compared with all occupations (odds ratio 1.73, 95% confidence interval 1.16–2.58). The prevalence of adverse psychosocial work characteristics did not follow the pattern of CMD by occupation. Work characteristics did not explain the increased risk of CMDs associated with working in personal service occupations. Contrary to our hypotheses, adding work characteristics individually to the association of occupation and CMD tended to increase rather than decrease the odds for CMD.

Conclusions

As has been found by others, psychosocial work characteristics were associated with CMD. However, we found that in our English national dataset they could not explain the high rates of CMD in particular occupations. We suggest that selection into occupations may partly explain high CMD rates in certain occupations. Also, we did not measure emotional demands, and these may be important mediators of the relationship between occupation type and CMDs.
The extra burdens patients in denial impose on their family caregivers
Authors: Kogan Naomi R. , Dumas Michelle , Cohen S. Robin
Published: August 2012

Objective:

The purpose of this study was to explore the impact of advanced cancer patients' denial on their family caregivers and how they cope, in order to enable clinicians to better support them and their caregiving.

Method:

As the objective was to obtain clinically useful findings, an interpretive descriptive design was used. Data consisted of prospective semi-structured interviews with 16 family caregivers of advanced cancer patients in denial, field notes, reflexive journals, and memos during the analysis.

Results:

Caregivers experienced extra burdens with the patient's denial. Feeling bound to preserve the denial, which they perceived as immutable, they were prevented from seeking information to manage the patient's care. Additionally, those caring for noncompliant patients felt disenfranchised from their role, resulting in feelings of powerlessness and guilt, and felt burdened by managing medical situations that arose from noncompliance. Caregivers described the ambivalence of feeling frustrated and burdened by the denial while recognizing it as a long-standing coping pattern for the patient. The denial prevented them from acknowledging their own needs to the patients or seeking informal support. They therefore developed solitary coping strategies, sought professional psychosocial support, and/or employed denial themselves.

Significance of results:

Caregivers of patients in denial experience added burdens, which they must bear without most of the usual sources of support. The burden is accentuated when patients are noncompliant with care, placing themselves in dangerous situations. Healthcare providers should identify patients in denial and support their caregivers in meeting both their caregiving and their own needs. Evidence-based strategies to accomplish this should be developed and implemented.
Suchtmittelkonsum bei homo- und bisexuellen Männern
Authors: Dirks Henrike , Esser Stefan , Specka Michael , Scherbaum Norbert
Published: August 2012

Hintergrund: Der Anteil von Männern, die Sex mit Männern haben (MSM) ist unter HIV-Neuinfizierten in vielen westlichen Industriestaaten konstant auf hohem Niveau. Die Einnahme von Suchtmitteln ist mit vermehrtem Risikoverhalten für sexuell übertragbare Krankheiten assoziiert. Der Suchtmittelkonsum von MSM und seine Assoziation mit sexuellem Risikoverhalten sind von Bedeutung für die HIV-Verbreitung. Methodik: Literaturübersicht ab 1999 publizierter Studien zur Prävalenz von Suchtmittelkonsum bei MSM. Ergebnisse: Die meisten Untersuchungen zum Thema wurden in den USA durchgeführt. Das Ausmaß von Alkoholkonsum und alkoholbezogenen Störungen bei MSM war generell vergleichbar mit der Allgemeinbevölkerung. Erhöhte Prävalenzraten unter MSM wurden für den Konsum illegaler Substanzen gefunden. Besonders für Cannabis, Amylnitrit, Halluzinogenen, Stimulantien und Kokain. Es gibt zudem Subgruppen von MSM, die im Kontext gesellschaftlicher Aktivitäten intensiv sog. Club Drugs konsumieren. Dieser Konsum ist mit sexuellem Risikoverhalten assoziiert. Schlussfolgerungen: Bei der Entwicklung zielgruppenspezifischer Interventionen zur Prävention sexuell übertragbarer Krankheiten in der Gruppe der MSM sollte der Suchtmittelkonsum als wichtiger Einflussfaktor verstärkt berücksichtigt werden.
Fixed nitrogen loss from the eastern tropical North Pacific and Arabian Sea oxygen deficient zones determined from measurements of N2:Ar
Authors: Chang Bonnie X. , Devol Allan H. , Emerson Steven R.
Published: August 2012

Previous work estimating the N2excess above background due to denitrification has suggested that nitrate deficit‐type methods may be an underestimate of fixed nitrogen (N) loss in the major oxygen deficient zones of the ocean. The N2excess approach has the advantage over nitrate deficit‐type methods in that it does not depend on stoichiometric assumptions of fixed N to phosphate or oxygen utilization and avoids any uncertainly regarding the pathway of N loss. Measurements of N2:Ar from two stations within the eastern tropical North Pacific and from one station within the Arabian Sea oxygen deficient zones were used to determine the N2 excess due to denitrification. In both of the regions, the N2 excess was comparable in shape and magnitude to the concurrent fixed nitrogen deficit. In the eastern tropical North Pacific oxygen deficient zone, the N2 excess was near zero at the surface and rose to maxima of 13.7 ± 1.8 and 10.8 ± 1.9 μM N, compared to maximum fixed N deficits of 13.5 ± 1.5 and 12.3 ± 1.5 μM N, respectively. In the Arabian Sea oxygen deficient zone, the maximum N2 excess was 11.1 ± 1.5 μM N, compared to a maximum deficit of 12.5 ± 1.0 μM N. These results suggests that previous estimates of fixed N loss based on fixed N deficit calculations in these regions are likely reasonable, given the same considerations of volume and residence time of the water of the oxygen deficient zone.
Is there a 60‐year oscillation in global mean sea level?
Authors: Chambers Don P. , Merrifield Mark A. , Nerem R. Steven
Published: August 2012

We examine long tide gauge records in every ocean basin to examine whether a quasi 60‐year oscillation observed in global mean sea level (GMSL) reconstructions reflects a true global oscillation, or an artifact associated with a small number of gauges. We find that there is a significant oscillation with a period around 60‐years in the majority of the tide gauges examined during the 20th Century, and that it appears in every ocean basin. Averaging of tide gauges over regions shows that the phase and amplitude of the fluctuations are similar in the North Atlantic, western North Pacific, and Indian Oceans, while the signal is shifted by 10 years in the western South Pacific. The only sampled region with no apparent 60‐year fluctuation is the Central/Eastern North Pacific. The phase of the 60‐year oscillation found in the tide gauge records is such that sea level in the North Atlantic, western North Pacific, Indian Ocean, and western South Pacific has been increasing since 1985–1990. Although the tide gauge data are still too limited, both in time and space, to determine conclusively that there is a 60‐year oscillation in GMSL, the possibility should be considered when attempting to interpret the acceleration in the rate of global and regional mean sea level rise.
Vertical winds in the thermosphere
Authors: Larsen M. F. , Meriwether J. W.
Published: August 2012

The neutral vertical circulation in the thermosphere plays an important role in redistributing heat and momentum and strongly affects the neutral composition, as well as plasma and electrodynamic processes. Vertical wind measurements in this altitude range are difficult, however, and the available data give limited temporal, spatial, and vertical coverage. The available ground‐based techniques are generally limited to narrow altitude ranges but provide more extended temporal coverage. The in situ techniques provide more extended altitude range coverage but have very limited temporal coverage. The most extensive measurements have come from ground‐based optical techniques using the 630.0‐nm F‐region red‐line emission and to a lesser extent the 557.7‐nm E‐region green‐line emission. A general characteristic of these measurements is that they often show large vertical wind speeds that persist for periods of several hours or longer at the same location. The large winds have been difficult to verify because of the difficulties associated with obtaining overlapping measurements and with obtaining a sufficiently comprehensive set of measurements to understand the dynamical drivers for the vertical winds. A surprising conclusion from examining all the available measurements, however, is that there is remarkable consistency between the characteristics of the thermospheric vertical velocities measured by different techniques and at different locations. We give an overview of the available data and find that, when considered together, the available observations all show the following patterns. Vertical velocities with magnitudes of 10–20 m s−1 are common at high latitudes, but also at mid and low latitudes. There is a slight tendency for the winds to increase with height from the E region to the F region, but the increase with height is small, and in particular, is much less than expected from the decrease of background density with altitude. Another surprising characteristic that holds true across altitudes and latitudes is that the large vertical winds frequently persist for extended periods of an hour or longer. The drivers for the observed events of large vertical winds are unknown, but the winds clearly have important implications for the dynamics, electrodynamics, plasma physics, and chemistry of the thermosphere.
A new global river network database for macroscale hydrologic modeling
Authors: Wu Huan , Kimball John S. , Li Hongyi , Huang Maoyi , Leung L. Ruby , Adler Robert F.
Published: August 2012

Coarse‐resolution (upscaled) river networks are critical inputs for runoff routing in macroscale hydrologic models. Recently, Wu et al. (2011) developed a hierarchical dominant river tracing (DRT) algorithm for automated extraction and spatial upscaling of river networks using fine‐scale hydrography inputs. We applied the DRT algorithms using combined HydroSHEDS and HYDRO1k global fine‐scale hydrography inputs and produced a new series of upscaled global river network data at multiple (1/16° to 2°) spatial resolutions. The new upscaled results are internally consistent and congruent with the baseline fine‐scale inputs and should facilitate improved regional to global scale hydrologic simulations.
Temperature stability of (Pt/Co)3/IrMn multilayers
Authors: Lechevallier L. , Zarefy A. , Letellier F. , Lardé R. , Blavette D. , Le Breton J. M. , Baltz V. , Rodmacq B. , Dieny B.
Published: August 2012

The effect of annealing on the structural stability of (Pt2nm/Co0.4 nm)3/IrMn7nm multilayers has been investigated using atom probe tomography. The composition of individual layers was measured after annealing at 300, 400, 500, and 700 °C. While results show that the (Pt/Co)3/IrMn stacking sequence is preserved up to 400 °C, there is an almost complete destruction of the multilayered structure when annealing at higher temperatures (500 and 700 °C). Co layers no more alternate with Pt-rich layers. The whole stack is transformed into an IrCo/PtMn bilayer. These results are interpreted on the basis of atomic mobilities and chemical affinities. Diffusion of Co and Mn is shown to become important when annealing temperature approaches 500 °C. Results are well accounted for by thermodynamics arguments considering the Co-Ir and Pt-Mn phase diagrams.
Asymmetric explosion of clusters in intense laser fields
Authors: Kundu M.
Published: August 2012

We examine asymmetric expansion of argon clusters illuminated by 800 nm laser pulses of duration ≈23fs, using three-dimensional particle-in-cell (PIC) simulation. For this short pulse duration, laser energy absorption by cluster electrons is dominated by the nonlinear resonance (NLR) absorption process [Phys. Rev. Lett. 96, 123401 (2006)]. In this work, we concentrate, particularly, on the ionic outcome in the NLR regime and show that higher charge states of argon ions are produced along the laser polarization than in the transverse directions leading to the anisotropy (asymmetry) in the ion energy distribution. This anisotropy already established during the short pulse duration (or in the early duration of a long pulse) may contribute to the anisotropic ion emission reported in cluster experiments with pulse duration longer than 100 fs. Our PIC results are compared with a charged-sphere model showing that cluster explosion is mainly due to Coulomb repulsion between the cluster ions.
On apparent temperature in low-frequency Alfvénic turbulence
Authors: Nariyuki Yasuhiro
Published: August 2012

Low-frequency, parallel propagating Alfvénic turbulence in collisionless plasmas is theoretically studied. Alfvénic turbulence is derived as an equilibrium state (Beltrami field) in the magnetohydrodynamic equations with the pressure anisotropy and multi-species of ions. It is shown that the conservation of the total “apparent temperature” corresponds to the Bernoulli law. A simple model of the radially expanding solar wind including Alfvénic turbulence is also discussed. The conversion of the wave energy in the “apparent temperature” into the “real temperature” is facilitated with increasing radial distance.
Thomson scattering in short pulse laser experiments
Authors: Hill E. G. , Rose S. J.
Published: August 2012

Thomson scattering is well used as a diagnostic in many areas of high energy density physics. In this paper, we quantitatively demonstrate the practicality of using Thomson scattering as a diagnostic of short-pulse laser-plasma experiments in the regime, where the plasmas probed are at solid density and have temperatures of many hundreds of eV using a backlighter produced with an optical laser. This method allows a diagnosis both spatially and temporally of the density and temperature distributions in high energy density laser-plasma interactions which is independent from, and would act as a useful complement to, the existing spectroscopic methods.
Evidence for discrete-state processing in recognition memory
Authors: Province Jordan M. , Rouder Jeffrey N.
Published: August 2012

We provide evidence that recognition memory is mediated by a detect-or-guess mental-state model without recourse to concepts of latent-strength or multiple-memory systems. We assess performance in a two-alternative forced-choice recognition memory task with confidence ratings. The key manipulation is that sometimes participants are asked which of two new items is old, and the resulting confidence distribution is unambiguously interpreted as arising from a guessing state. The confidence ratings for other conditions are seemingly the resultant of mixing this stable guessing state with an additional stable detect state. Formal model comparison supports this observation, and an analysis of associated response times reveals a mixture signature as well.
How actin network dynamics control the onset of actin-based motility
Authors: Kawska Agnieszka , Carvalho Kévin , Manzi John , Boujemaa-Paterski Rajaa , Blanchoin Laurent , Martiel Jean-Louis , Sykes Cécile
Published: August 2012

Cells use their dynamic actin network to control their mechanics and motility. These networks are made of branched actin filaments generated by the Arp2/3 complex. Here we study under which conditions the microscopic organization of branched actin networks builds up a sufficient stress to trigger sustained motility. In our experimental setup, dynamic actin networks or “gels” are grown on a hard bead in a controlled minimal protein system containing actin monomers, profilin, the Arp2/3 complex and capping protein. We vary protein concentrations and follow experimentally and through simulations the shape and mechanical properties of the actin gel growing around beads. Actin gel morphology is controlled by elementary steps including “primer” contact, growth of the network, entanglement, mechanical interaction and force production. We show that varying the biochemical orchestration of these steps can lead to the loss of network cohesion and the lack of effective force production. We propose a predictive phase diagram of actin gel fate as a function of protein concentrations. This work unveils how, in growing actin networks, a tight biochemical and physical coupling smoothens initial primer-caused heterogeneities and governs force buildup and cell motility.
Warming-induced shift in European mushroom fruiting phenology
Authors: Kauserud Håvard , Heegaard Einar , Büntgen Ulf , Halvorsen Rune , Egli Simon , Senn-Irlet Beatrice , Krisai-Greilhuber Irmgard , Dämon Wolfgang , Sparks Tim , Nordén Jenni , Høiland Klaus , Kirk Paul , Semenov Mikhail , Boddy Lynne , Stenseth Nils C.
Published: August 2012

In terrestrial ecosystems, fungi are the major agents of decomposition processes and nutrient cycling and of plant nutrient uptake. Hence, they have a vital impact on ecosystem processes and the terrestrial carbon cycle. Changes in productivity and phenology of fungal fruit bodies can give clues to changes in fungal activity, but understanding these changes in relation to a changing climate is a pending challenge among ecologists. Here we report on phenological changes in fungal fruiting in Europe over the past four decades. Analyses of 746,297 dated and geo-referenced mushroom records of 486 autumnal fruiting species from Austria, Norway, Switzerland, and the United Kingdom revealed a widening of the annual fruiting season in all countries during the period 1970–2007. The mean annual day of fruiting has become later in all countries. However, the interspecific variation in phenological responses was high. Most species moved toward a later ending of their annual fruiting period, a trend that was particularly strong in the United Kingdom, which may reflect regional variation in climate change and its effects. Fruiting of both saprotrophic and mycorrhizal fungi now continues later in the year, but mycorrhizal fungi generally have a more compressed season than saprotrophs. This difference is probably due to the fruiting of mycorrhizal fungi partly depending on cues from the host plant. Extension of the European fungal fruiting season parallels an extended vegetation season in Europe. Changes in fruiting phenology imply changes in mycelia activity, with implications for ecosystem function.
Eilat virus, a unique alphavirus with host range restricted to insects by RNA replication
Authors: Nasar Farooq , Palacios Gustavo , Gorchakov Rodion V. , Guzman Hilda , Da Rosa Amelia P. Travassos , Savji Nazir , Popov Vsevolod L. , Sherman Michael B. , Lipkin W. Ian , Tesh Robert B. , Weaver Scott C.
Published: August 2012

Most alphaviruses and many other arboviruses are mosquito-borne and exhibit a broad host range, infecting many different vertebrates including birds, rodents, equids, humans, and nonhuman primates. Consequently, they can be propagated in most vertebrate and insect cell cultures. This ability of arboviruses to infect arthropods and vertebrates is usually essential for their maintenance in nature. However, several flaviviruses have recently been described that infect mosquitoes but not vertebrates, although the mechanism of their host restriction has not been determined. Here we describe a unique alphavirus, Eilat virus (EILV), isolated from a pool of
Anopheles coustani
mosquitoes from the Negev desert of Israel. Phylogenetic analyses placed EILV as a sister to the Western equine encephalitis antigenic complex within the main clade of mosquito-borne alphaviruses. Electron microscopy revealed that, like other alphaviruses, EILV virions were spherical, 70 nm in diameter, and budded from the plasma membrane of mosquito cells in culture. EILV readily infected a variety of insect cells with little overt cytopathic effect. However, in contrast to typical mosquito-borne alphaviruses, EILV could not infect mammalian or avian cell lines, and viral as well as RNA replication could not be detected at 37 °C or 28 °C. Evolutionarily, these findings suggest that EILV lost its ability to infect vertebrate cells. Thus, EILV seems to be mosquito-specific and represents a previously undescribed complex within the genus
Alphavirus
. Reverse genetic studies of EILV may facilitate the discovery of determinants of alphavirus host range that mediate disease emergence.
Mouse lipin-1 and lipin-2 cooperate to maintain glycerolipid homeostasis in liver and aging cerebellum
Authors: Dwyer Jennifer R. , Donkor Jimmy , Zhang Peixiang , Csaki Lauren S. , Vergnes Laurent , Lee Jessica M. , Dewald Jay , Brindley David N. , Atti Elisa , Tetradis Sotirios , Yoshinaga Yuko , De Jong Pieter J. , Fong Loren G. , Young Stephen G. , Reue Karen
Published: August 2012

The three lipin phosphatidate phosphatase (PAP) enzymes catalyze a step in glycerolipid biosynthesis, the conversion of phosphatidate to diacylglycerol. Lipin-1 is critical for lipid synthesis and homeostasis in adipose tissue, liver, muscle, and peripheral nerves. Little is known about the physiological role of lipin-2, the predominant lipin protein present in liver and the deficient gene product in the rare disorder Majeed syndrome. By using lipin-2–deficient mice, we uncovered a functional relationship between lipin-1 and lipin-2 that operates in a tissue-specific and age-dependent manner. In liver, lipin-2 deficiency led to a compensatory increase in hepatic lipin-1 protein and elevated PAP activity, which maintained lipid homeostasis under basal conditions, but led to diet-induced hepatic triglyceride accumulation. As lipin-2–deficient mice aged, they developed ataxia and impaired balance. This was associated with the combination of lipin-2 deficiency and an age-dependent reduction in cerebellar lipin-1 levels, resulting in altered cerebellar phospholipid composition. Similar to patients with Majeed syndrome, lipin-2–deficient mice developed anemia, but did not show evidence of osteomyelitis, suggesting that additional environmental or genetic components contribute to the bone abnormalities observed in patients. Combined lipin-1 and lipin-2 deficiency caused embryonic lethality. Our results reveal functional interactions between members of the lipin family in vivo, and a unique role for lipin-2 in central nervous system biology that may be particularly important with advancing age. Additionally, as has been observed in mice and humans with lipin-1 deficiency, the pathophysiology in lipin-2 deficiency is associated with dysregulation of lipid intermediates.
Hydration repulsion between biomembranes results from an interplay of dehydration and depolarization
Authors: Schneck Emanuel , Sedlmeier Felix , Netz Roland R.
Published: August 2012

Hydration repulsion dominates the interaction between polar surfaces in water at nanometer separations and ultimately prevents the sticking together of biological matter. Although confirmed by a multitude of experimental methods for various systems, its mechanism remained unclear. A simulation technique is introduced that yields accurate pressures between solvated surfaces at prescribed water chemical potential and is applied to a stack of phospholipid bilayers. Experimental pressure data are quantitatively reproduced and the simulations unveil a rich microscopic picture: Direct membrane–membrane interactions are attractive but overwhelmed by repulsive indirect water contributions. Below about 17 water molecules per lipid, this indirect repulsion is of an energetic nature and due to desorption of hydration water; for larger hydration it is entropic and suggested to involve water depolarization. This antagonistic nature and the presence of various compensating contributions indicate that the hydration repulsion is less universal than previously assumed and rather involves finely tuned surface-water interactions.
The nerve of ovulation-inducing factor in semen
Authors: Ratto Marcelo H. , Leduc Yvonne A. , Valderrama Ximena P. , van Straaten Karin E. , Delbaere Louis T. J. , Pierson Roger A. , Adams Gregg P.
Published: August 2012

A component in seminal fluid elicits an ovulatory response and has been discovered in every species examined thus far. The existence of an ovulation-inducing factor (OIF) in seminal plasma has broad implications and evokes questions about identity, tissue sources, mechanism of action, role among species, and clinical relevance in infertility. Most of these questions remain unanswered. The goal of this study was to determine the identity of OIF in support of the hypothesis that it is a single distinct and widely conserved entity. Seminal plasma from llamas and bulls was used as representative of induced and spontaneous ovulators, respectively. A fraction isolated from llama seminal plasma by column chromatography was identified as OIF by eliciting luteinizing hormone (LH) release and ovulation in llamas. MALDI-TOF revealed a molecular mass of 13,221 Da, and 12–23 aa sequences of OIF had homology with human, porcine, bovine, and murine sequences of β nerve growth factor (β-NGF). X-ray diffraction data were used to solve the full sequence and structure of OIF as β-NGF. Neurite development and up-regulation of trkA in phaeochromocytoma (PC
12
) cells in vitro confirmed NGF-like properties of OIF. Western blot analysis of llama and bull seminal plasma confirmed immunorecognition of OIF using polyclonal mouse anti-NGF, and administration of β-NGF from mouse submandibular glands induced ovulation in llamas. We conclude that OIF in seminal plasma is β-NGF and that it is highly conserved. An endocrine route of action of NGF elucidates a previously unknown pathway for the direct influence of the male on the hypothalamo–pituitary–gonadal axis of the inseminated female.
Impact of abrupt deglacial climate change on tropical Atlantic subsurface temperatures
Authors: Schmidt Matthew W. , Chang Ping , Hertzberg Jennifer E. , Them Theodore R. , Ji Link , Otto-Bliesner Bette L.
Published: August 2012

Both instrumental data analyses and coupled ocean-atmosphere models indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly linked to abrupt tropical North Atlantic (TNA) climate change through both atmospheric and oceanic processes. Although a slowdown of AMOC results in an atmospheric-induced surface cooling in the entire TNA, the subsurface experiences an even larger warming because of rapid reorganizations of ocean circulation patterns at intermediate water depths. Here, we reconstruct high-resolution temperature records using oxygen isotope values and Mg/Ca ratios in both surface- and subthermocline-dwelling planktonic foraminifera from a sediment core located in the TNA over the last 22 ky. Our results show significant changes in the vertical thermal gradient of the upper water column, with the warmest subsurface temperatures of the last deglacial transition corresponding to the onset of the Younger Dryas. Furthermore, we present new analyses of a climate model simulation forced with freshwater discharge into the North Atlantic under Last Glacial Maximum forcings and boundary conditions that reveal a maximum subsurface warming in the vicinity of the core site and a vertical thermal gradient change at the onset of AMOC weakening, consistent with the reconstructed record. Together, our proxy reconstructions and modeling results provide convincing evidence for a subsurface oceanic teleconnection linking high-latitude North Atlantic climate to the tropical Atlantic during periods of reduced AMOC across the last deglacial transition.
Regulation of cell size in response to nutrient availability by fatty acid biosynthesis in
Escherichia coli
Authors: Yao Zhizhong , Davis Rebecca M. , Kishony Roy , Kahne Daniel , Ruiz Natividad
Published: August 2012

Cell size varies greatly among different types of cells, but the range in size that a specific cell type can reach is limited. A long-standing question in biology is how cells control their size.
Escherichia coli
adjusts size and growth rate according to the availability of nutrients so that it grows larger and faster in nutrient-rich media than in nutrient-poor media. Here, we describe how, using classical genetics, we have isolated a remarkably small
E. coli
mutant that has undergone a 70% reduction in cell volume with respect to wild type. This mutant lacks FabH, an enzyme involved in fatty acid biosynthesis that previously was thought to be essential for the viability of
E. coli
. We demonstrate that although FabH is not essential in wild-type
E. coli
, it is essential in cells that are defective in the production of the small-molecule and global regulator ppGpp. Furthermore, we have found that the loss of FabH causes a reduction in the rate of envelope growth and renders cells unable to regulate cell size properly in response to nutrient excess. Therefore we propose a model in which fatty acid biosynthesis plays a central role in regulating the size of
E. coli
cells in response to nutrient availability.
Specific deletion of Na
V
1.1 sodium channels in inhibitory interneurons causes seizures and premature death in a mouse model of Dravet syndrome
Authors: Cheah Christine S. , Yu Frank H. , Westenbroek Ruth E. , Kalume Franck K. , Oakley John C. , Potter Gregory B. , Rubenstein John L. , Catterall William A.
Published: August 2012

Heterozygous loss-of-function mutations in the brain sodium channel Na
V
1.1 cause Dravet syndrome (DS), a pharmacoresistant infantile-onset epilepsy syndrome with comorbidities of cognitive impairment and premature death. Previous studies using a mouse model of DS revealed reduced sodium currents and impaired excitability in GABAergic interneurons in the hippocampus, leading to the hypothesis that impaired excitability of GABAergic inhibitory neurons is the cause of epilepsy and premature death in DS. However, other classes of GABAergic interneurons are less impaired, so the direct cause of hyperexcitability, epilepsy, and premature death has remained unresolved. We generated a floxed
Scn1a
mouse line and used the Cre-Lox method driven by an enhancer from the
Dlx
1,2 locus for conditional deletion of
Scn1a
in forebrain GABAergic neurons. Immunocytochemical studies demonstrated selective loss of Na
V
1.1 channels in GABAergic interneurons in cerebral cortex and hippocampus. Mice with this deletion died prematurely following generalized tonic-clonic seizures, and they were equally susceptible to thermal induction of seizures as mice with global deletion of
Scn1a
. Evidently, loss of Na
V
1.1 channels in forebrain GABAergic neurons is both necessary and sufficient to cause epilepsy and premature death in DS.
Membrane physical properties influence transmembrane helix formation
Authors: Barrera Francisco N. , Fendos Justin , Engelman Donald M.
Published: August 2012

The pHLIP peptide has three states: (I) soluble in aqueous buffer, (II) bound to the bilayer surface at neutral pH, and (III) inserted as a transmembrane (TM) helix at acidic pH. The membrane insertion of pHLIP at low pH can be used to target the acidic tissues characteristic of different diseases, such as cancer. We find that the α-helix content of state II depends on lipid acyl chain length but not cholesterol, suggesting the helicity of the bound state may be controlled by the bilayer elastic bending modulus. Experiments with the P20G variant show the proline residue in pHLIP reduces the α-helix content of both states II and III. We also observe that the membrane insertion pKa is influenced by membrane physical properties, following a biphasic pattern similar to the membrane thickness optima observed for the function of eukaryotic membrane proteins. Because tumor cells exhibit altered membrane fluidity, we suggest this might influence pHLIP tumor targeting. We used a cell insertion assay to determine the pKa in live cells, observing that the properties in liposomes held in the more complex plasma membrane. Our results show that the formation of a TM helix is modulated by both the conformational propensities of the peptide and the physical properties of the bilayer. These results suggest a physical role for helix-membrane interactions in optimizing the function of more complex TM proteins.
The vocational curriculum in the lower secondary school: material and discursive practices
Authors: Canning Roy
Published: August 2012

The rationale for the study is to enhance our understanding of how young people learn and engage with vocational subjects within the lower secondary years of compulsory education. The concept of pre‐vocational education has recently emerged to describe the initial transitional phase of preparing young people for employment in specific occupational areas in the UK. Although there has been extensive research undertaken in work‐based apprenticeship learning, very little research has emerged in pre‐vocational education among 14–16 year olds in schools. The research undertakes such an enquiry based upon a case study of North Lanarkshire secondary schools. This local authority has been selected as it has one of the highest rates of young people participating in pre‐vocational education in secondary education and has been identified by a recent OECD report as a potential exemplar of best practice in this field. However, concerns remain regarding how to integrate the pre‐vocational curriculum with the academic curriculum, whether pre‐vocational courses can engage high achievers and, more specifically, how effectively the subject is taught within schools.
‘It wasn't too easy, which is good if you want to learn’: an exploration of pupil participation and Learning to Learn
Authors: Wall Kate
Published: August 2012

This article explores the process of Learning to Learn from the pupils’ perspective. The Learning to Learn in Schools Project started in 2003 and includes teachers and pupils from primary and secondary age phases in four local authorities. Key to the project has been a focus on the collaborative exploration of metacognition in practice. With the increased prominence of pupil participation and learner voice in the rhetoric of education during this time, the inclusion of learner perspectives in the project was perhaps inevitable. However, there appears to be something beneficial about the definition of Learning to Learn (L2L) used by the project that supports the development of such participation. As the project progressed, and the incidence of pupil participation increased, evidence from the contexts needed to support learning‐based dialogues also developed as well as, crucially, understanding of how the interplay between L2L and pupil participation operates. This article therefore explores the link between the rhetoric of the pupil participation agenda and an understanding of L2L from the pupils’ perspective.
Endothelial Wnt/β-catenin signaling inhibits glioma angiogenesis and normalizes tumor blood vessels by inducing PDGF-B expression
Authors: Reis Marco , Czupalla Cathrin J. , Ziegler Nicole , Devraj Kavi , Zinke Jenny , Seidel Sascha , Heck Rosario , Thom Sonja , Macas Jadranka , Bockamp Ernesto , Fruttiger Marcus , Taketo Makoto M. , Dimmeler Stefanie , Plate Karl H. , Liebner Stefan
Published: August 2012

Endothelial Wnt/β-catenin signaling is necessary for angiogenesis of the central nervous system and blood–brain barrier (BBB) differentiation, but its relevance for glioma vascularization is unknown. In this study, we show that doxycycline-dependent Wnt1 expression in subcutaneous and intracranial mouse glioma models induced endothelial Wnt/β-catenin signaling and led to diminished tumor growth, reduced vascular density, and normalized vessels with increased mural cell attachment. These findings were corroborated in GL261 glioma cells intracranially transplanted in mice expressing dominant-active β-catenin specifically in the endothelium. Enforced endothelial β-catenin signaling restored BBB characteristics, whereas inhibition by Dkk1 (Dickkopf-1) had opposing effects. By overactivating the Wnt pathway, we induced the Wnt/β-catenin–Dll4/Notch signaling cascade in tumor endothelia, blocking an angiogenic and favoring a quiescent vascular phenotype, indicated by induction of stalk cell genes. We show that β-catenin transcriptional activity directly regulated endothelial expression of platelet-derived growth factor B (PDGF-B), leading to mural cell recruitment thereby contributing to vascular quiescence and barrier function. We propose that reinforced Wnt/β-catenin signaling leads to inhibition of angiogenesis with normalized and less permeable vessels, which might prove to be a valuable therapeutic target for antiangiogenic and edema glioma therapy.
Origin of a needle-like granular structure for ultrananocrystalline diamond films grown in a N2/CH4 plasma
Authors: Sankaran K J , Kurian J , Chen H C , Dong C L , Lee C Y , Tai N H , Lin I N
Published: August 2012

Microstructural evolution as a function of substrate temperature (T
S) for conducting ultrananocrystalline diamond (UNCD) films is systematically studied. Variation of the sp2 graphitic and sp3 diamond content with T
S in the films is analysed from the Raman and near-edge x-ray absorption fine structure spectra. Morphological and microstructural studies confirm that at T
S = 700 °C well-defined acicular structures evolve. These nanowire structures comprise sp3 phased diamond, encased in a sheath of sp2 bonded graphitic phase. T
S causes a change in morphology and thereby the various properties of the films. For T
S = 800 °C the acicular grain growth ceases, while that for T
S = 700 °C ceases only upon termination of the deposition process. The grain-growth process for the unique needle-like granular structure is proposed such that the CN species invariably occupy the tip of the nanowire, promoting an anisotropic grain-growth process and the formation of acicular structure of the grains. The electron field emission studies substantiate that the films grown at T
S = 700 °C are the most conducting, with conduction mediated through the graphitic phase present in the films.
Hopf algebras with triality
Authors: Benkart Georgia , Madariaga Sara , Pérez-Izquierdo José
Published: August 2012

In this paper we revisit and extend the constructions of Glauberman and Doro on groups with triality and Moufang loops to Hopf algebras. We prove that the universal enveloping algebra of any Lie algebra with triality is a Hopf algebra with triality. This allows us to give a new construction of the universal enveloping algebras of Malcev algebras. Our work relies on the approach of Grishkov and Zavarnitsine to groups with triality.
FACETS: multi-faceted functional decomposition of protein interaction networks
Authors: Seah Boon-Siew , Bhowmick Sourav S. , Forbes Dewey C.
Published: August 2012

Motivation: The availability of large-scale curated protein interaction datasets has given rise to the opportunity to investigate higher level organization and modularity within the protein–protein interaction (PPI) network using graph theoretic analysis. Despite the recent progress, systems level analysis of high-throughput PPIs remains a daunting task because of the amount of data they present. In this article, we propose a novel PPI network decomposition algorithm called FACETS in order to make sense of the deluge of interaction data using Gene Ontology (GO) annotations. FACETS finds not just a single functional decomposition of the PPI network, but a multi-faceted atlas of functional decompositions that portray alternative perspectives of the functional landscape of the underlying PPI network. Each facet in the atlas represents a distinct interpretation of how the network can be functionally decomposed and organized. Our algorithm maximizes interpretative value of the atlas by optimizing inter-facet orthogonality and intra-facet cluster modularity.

Results: We tested our algorithm on the global networks from IntAct, and compared it with gold standard datasets from MIPS and KEGG. We demonstrated the performance of FACETS. We also performed a case study that illustrates the utility of our approach.

Contact:  seah0097@ntu.edu.sg or assourav@ntu.edu.sg

Supplementary information:  Supplementary data are available at the Bioinformatics online.

Availability: Our software is available freely for non-commercial purposes from: http://www.cais.ntu.edu.sg/∼assourav/Facets/
Satellite remote sensing of primary productivity in the Bering and Chukchi Seas using an absorption-based approach
Authors: Hirawake Toru , Shinmyo Katsuhito , Fujiwara Amane , Saitoh Sei-ichi
Published: August 2012

Hirawake, T., Shinmyo, K., Fujiwara, A., and Saitoh, S. 2012. Satellite remote sensing of primary productivity in the Bering and Chukchi Seas using an absorption-based approach. – ICES Journal of Marine Science, 69: . Ocean colour remote sensing has been utilized for studying primary productivity in the Arctic Ocean. However, phytoplankton chlorophyll a (Chl a) is not predicted accurately because of the interference of coloured dissolved organic matter (CDOM) and non-algal particles (NAP). To enhance the estimation accuracy, a phytoplankton absorption-based primary productivity model (ABPM) was applied to the Bering and Chukchi Seas. The phytoplankton absorption coefficient was determined correctly from sea surface remote sensing reflectance (Rrs) and reduced the effect of CDOM and NAP in primary productivity (PPeu) estimates. PPeu retrieved from in situ Rrs using the ABPM satisfied a factor of 2 of measured values. PPeu estimated from the Moderate Resolution Imaging Spectroradiometer Rrs data were within the range of historical values. These estimated PPeu values were less than half of those of the model based on Chl a, and the difference between the two models reflected the influence of CDOM and NAP absorptions. Interannual variation in August and September over the period 2002–2010 showed an increase in primary productivity. The increase in 2007 was especially large, by a factor of 1.51–2.71, compared with 2006. The significant temporal increase in productivity detected here differs from earlier studies that detected little, if any, change in the region.
Proteomic Analysis of Chloroplast-to-Chromoplast Transition in Tomato Reveals Metabolic Shifts Coupled with Disrupted Thylakoid Biogenesis Machinery and Elevated Energy-Production Components
Authors: Barsan Cristina , Zouine Mohamed , Maza Elie , Bian Wanping , Egea Isabel , Rossignol Michel , Bouyssie David , Pichereaux Carole , Purgatto Eduardo , Bouzayen Mondher , Latché Alain , Pech Jean-Claude
Published: August 2012

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration) and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome.
Genotype–phenotype studies of VCP‐associated inclusion body myopathy with Paget disease of bone and/or frontotemporal dementia
Authors: Mehta SG , Khare M , Ramani R , Watts GDJ , Simon M , Osann KE , Donkervoort S , Dec E , Nalbandian A , Platt J , Pasquali M , Wang A , Mozaffar T , Smith CD , Kimonis VE
Published: August 2012

Valosin containing protein (VCP) disease associated with inclusion body myopathy, Paget disease of the bone and frontotemporal dementia is a progressive autosomal dominant disorder caused by mutations in Valosin containing protein gene. To establish genotype–phenotype correlations we analyzed clinical and biochemical markers from a database of 190 members in 27 families harboring 10 missense mutations. Individuals were grouped into three categories: symptomatic, presymptomatic carriers and noncarriers. The symptomatic families were further divided into ten groups based on their VCP mutations. There was marked intra and inter‐familial variation; and significant genotype–phenotype correlations were difficult to establish because of small numbers. Nevertheless when comparing the two most common mutations, R155C mutation was found to be more severe, with an earlier onset of myopathy and Paget (p = 0.03). Survival analysis of all subjects revealed an average life span after diagnosis of myopathy and Paget of 18 and 19 years respectively, and after dementia only 6 years. R155C had a reduced survival compared to the R155H mutation (p = 0.03).We identified amyotrophic lateral sclerosis (ALS) was diagnosed in 13 individuals (8.9%) and Parkinson's disease in five individuals (3%); however, there was no genotypic correlation. This study represents the largest dataset of patients with VCP disease and expands our understanding of the natural history and provides genotype–phenotype correlations in this unique disease.