bluuebunny/crossref_metadata_2025 huggingface dataset:
Early growth and markers of cardiovascular risk in Keralan children in the Integrated Child Development Scheme
Authors: Brown Nick , Sasidharan Chaniyil Krishnan , Fisher David
Published: September 2009

Objective

Low birth weight is associated with increased lifelong morbidity. Kerala has a renowned, low-cost, maternal–child health system in which is couched universal access to the Integrated Child Development Scheme (ICDS), central to which is community-based maternal–infant nutritional supplementation. We assessed whether children in this environment showed enhanced birth weight and postnatal growth and whether the evolution of early markers of CVD was attenuated in comparison to contemporaries from other states.

Design

A part retrospective, part prospective cohort study in which children (n 286) born in 1998–2000 in Calicut were identified from Anganwadi records. They were traced at 6 years and underwent full anthropometry and blood pressure measurements at 6 and 8 years.

Results

Mean birth weight (2·86 (sd 0·40) kg) was greater than in Indian contemporaries but consistently <−1sd below the National Center for Health Statistics reference median throughout childhood. Birth weight significantly predicted body mass (BMI) at 8 years. Lower birth weight was strongly predictive of a higher waist:hip ratio (WHR) indicative of adverse central (coelomic) fat distribution (P < 0·01). Faster weight gain in infancy was weakly predictive of a lower WHR (P = 0·59), but faster late childhood growth at 6–8 years was non-significantly predictive of adverse WHR.

Conclusions

At 8 years of age, children in Calicut participating in the ICDS have greater birth weight and relative attenuation of the evolution of early CVD markers compared with children in apparently comparable states. The relative contributions of the ICDS and other factors inherent to Kerala cannot be inferred from the present study.
Neutral‐ion interaction in the auroral E region obtained from coordinated Fabry‐Perot imager and VHF radar observations
Authors: Sakanoi T. , Fukunishi H. , Igarashi K. , Okano S. , Nishitani N.
Published: September 2009

It is important to investigate the small‐scale dynamics of thermospheric neutrals and ionospheric plasmas at high latitudes since there are local and temporal variations in energy input and transfer processes associated with auroral activities. To clarify these ionosphere‐thermosphere interactions in the auroral E region, we examined neutral winds and plasma motions obtained by coordinated Fabry‐Perot imager and VHF radar observations at Syowa Station, Antarctica. From case studies on 11 and 12 September 1996, we found a good correlation between temporal variation (period < 1 hr) of E region neutral winds measured by the Fabry‐Perot imager and the Doppler velocities of plasmas obtained from the VHF radar echoes. On the other hand, the absolute mean values of the neutral winds were around zero whereas the plasma Doppler velocities were 350–400 m/s, showing a significant discrepancy. Considering that the neutral‐ion and ion‐neutral momentum transfer collision frequencies in the E region are ∼10−6 Hz and ∼102 Hz, respectively, these good correlations are probably due to ion motions driven by neutral drag force, suggesting a strong coupling between neutrals and ions in the E region. The observed correlation and discrepancy between the radar Doppler velocity and the neutral wind velocity are consistent with the linear theory of E region irregularities that shows the radar Doppler velocity is the sum of two components; one is the E × B drift speed, and another is proportional to the neutral wind velocity.
Observations of marine stratocumulus microphysics and implications for processes controlling droplet spectra: Results from the Marine Stratus/Stratocumulus Experiment
Authors: Wang Jian , Daum Peter H. , Yum Seong Soo , Liu Yangang , Senum Gunnar I. , Lu Miao‐Ling , Seinfeld John H. , Jonsson Haflidi
Published: September 2009

During the Marine Stratus/Stratocumulus Experiment, cloud and aerosol microphysics were measured in the eastern Pacific off the coast of northern California on board Department of Energy Gulfstream‐1 in July 2005. Three cases with uniform aerosol concentration and minimal drizzle concentration were examined to study cloud microphysical behavior. For these three cases, the average droplet number concentration increased with increasing altitude, while the average interstitial aerosol concentration decreased with altitude. The data show enhanced growth of large droplets and spectral broadening in cloud parcels with low liquid water mixing ratio. Three mixing models, including inhomogeneous mixing, entity type entrainment mixing, and circulation mixing proposed in this study, are examined with regard to their influences on cloud microphysics. The observed cloud microphysical behavior is most consistent with the circulation mixing, which describes the mixing between cloud parcels with different lifting condensation levels during their circulations driven by evaporative and radiative cooling. The enhanced growth and spectrum broadening resulting from the circulation mixing reduce cloud albedo at the same liquid water path and facilitate the formation of precipitation embryos.
Arctic aerosol and clouds studied by bistatic lidar technique
Authors: Olofson K. Frans G. , Svensson Erik A. , Witt Georg , Pettersson Jan B. C.
Published: September 2009

Aerosol and cloud studies were carried out with a polarimetric bistatic lidar setup at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) in Andenes (69°N, 16E°), Norway. The measurements were performed from 10 to 23 October 2006 and covered altitudes between 1.5 and 11 km, corresponding to scattering angles between 130 and 170°. The degree of linear polarization, PL, calculated from the experiments was compared with light scattering calculations using Lorenz‐Mie theory for spherical particles, the T‐matrix approach for nonspherical rotationally symmetric particles, and a geometric optics ray‐tracing method. Average PL values between 0.61 and 0.72 were obtained for the background aerosol under cloud‐free conditions. The aerosol results may be qualitatively reproduced by standard aerosol types if a suitable combination of coarse‐ and fine‐mode spherical particles is assumed. The PL values obtained for thin and mildly opaque clouds were in the range from 0.21 to 0.38. These results were not well described by spherical particles, and the results for relatively small prolate and oblate particles studied with the T‐matrix method tended to be slightly higher than the experimental values. Geometric optics calculations for hexagonal column ice particles with surface roughness were able to reproduce the experimental cloud data. This does not rule out contributions from other types of particles, and particle orientation effects may also have influenced the results. We conclude that the experimental results are consistent with earlier in situ studies of cirrus clouds, and the further development and application of the bistatic lidar technique is discussed.
Development of a dust source database for mesoscale forecasting in southwest Asia
Authors: Walker Annette L. , Liu Ming , Miller Steven D. , Richardson Kim A. , Westphal Douglas L.
Published: September 2009

Numerous high‐resolution (1 km or better) images from satellite remote sensing platforms, i.e., space shuttle, Sea‐viewing Wide Field‐of‐view Sensor, and the Moderate Resolution Imaging Spectroradiometer, show dust plumes at the scale of 100 km originate from the merging of a multitude of point source plumes. These point source plumes stem from numerous point sources measuring 1–10s km across. Capitalizing on the Naval Research Laboratory's recently developed satellite derived 1‐km Dust Enhancement Product (DEP) imagery we can readily distinguish elevated dust over land from other components of the scene and identify the many small, eroding point sources that form the heads of point source plumes. On the basis of this approach, a high‐resolution (1‐km) dust source database (DSD) is created using 5 years (2001–2005) of DEP imagery for southwest Asia. The performance of the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) using the high‐resolution DSD is evaluated via a case study of a major dust event over Afghanistan, Iran, and Pakistan in October 2001. The results from our case study show that the improved specification of erodible land surfaces by use of a high‐resolution DSD allows COAMPS to accurately model the evolution of individual dust plumes and better forecast the onset and end of dust storm occurrence (i.e., low‐visibility conditions). Statistical analyses of the visibility predictions and dust storm occurrence show simulations using the high‐resolution DSD have the lowest false alarm rates and the highest total prediction skill among the other DSDs that were considered. This work contributes to the growing base of knowledge concerning the global dust cycle by identifying and mapping point sources in one of the world's foremost dust‐producing regions.
Climate change impact assessment: Uncertainty modeling with imprecise probability
Authors: Ghosh Subimal , Mujumdar P. P.
Published: September 2009

Hydrologic impacts of climate change are usually assessed by downscaling the General Circulation Model (GCM) output of large‐scale climate variables to local‐scale hydrologic variables. Such an assessment is characterized by uncertainty resulting from the ensembles of projections generated with multiple GCMs, which is known as intermodel or GCM uncertainty. Ensemble averaging with the assignment of weights to GCMs based on model evaluation is one of the methods to address such uncertainty and is used in the present study for regional‐scale impact assessment. GCM outputs of large‐scale climate variables are downscaled to subdivisional‐scale monsoon rainfall. Weights are assigned to the GCMs on the basis of model performance and model convergence, which are evaluated with the Cumulative Distribution Functions (CDFs) generated from the downscaled GCM output (for both 20th Century [20C3M] and future scenarios) and observed data. Ensemble averaging approach, with the assignment of weights to GCMs, is characterized by the uncertainty caused by partial ignorance, which stems from nonavailability of the outputs of some of the GCMs for a few scenarios (in Intergovernmental Panel on Climate Change [IPCC] data distribution center for Assessment Report 4 [AR4]). This uncertainty is modeled with imprecise probability, i.e., the probability being represented as an interval gray number. Furthermore, the CDF generated with one GCM is entirely different from that with another and therefore the use of multiple GCMs results in a band of CDFs. Representing this band of CDFs with a single valued weighted mean CDF may be misleading. Such a band of CDFs can only be represented with an envelope that contains all the CDFs generated with a number of GCMs. Imprecise CDF represents such an envelope, which not only contains the CDFs generated with all the available GCMs but also to an extent accounts for the uncertainty resulting from the missing GCM output. This concept of imprecise probability is also validated in the present study. The imprecise CDFs of monsoon rainfall are derived for three 30‐year time slices, 2020s, 2050s and 2080s, with A1B, A2 and B1 scenarios. The model is demonstrated with the prediction of monsoon rainfall in Orissa meteorological subdivision, which shows a possible decreasing trend in the future.
Seeding of equatorial plasma depletions by polarization electric fields from middle latitudes: Experimental evidence
Authors: Miller E. S. , Makela J. J. , Kelley M. C.
Published: September 2009

It is well‐known that large wedges of depleted plasma often form in the equatorial ionosphere after sunset. Irregularities in and around these depletions cause scintillation on trans‐ionospheric radio paths, as well as strong VHF backscatter. The ultimate stage of depletion growth is controlled by a collisional interchange instability. However, the initiation stages remain the subject of debate. Depletions formed in the first 1–3 hours after sunset are probably seeded by instability processes operating in the valley region from 150–250 km. However, depletions that form later in the evening do not benefit from the rapid pre‐reversal enhancement of the zonal electric field nor the sheared flow of the evening vortex. We investigate evidence from airglow images and VHF coherent backscatter that a polarization electric field associated with an ionospheric instability process at middle latitudes may induce the formation of post‐midnight depletions at the geomagnetic equator during geomagnetically‐quiet periods.
Estimation of the molecular hydrogen soil uptake and traffic emissions at a suburban site near Paris through hydrogen, carbon monoxide, and radon‐222 semicontinuous measurements
Authors: Yver C. , Schmidt M. , Bousquet P. , Zahorowski W. , Ramonet M.
Published: September 2009

Since June 2006, simultaneous semicontinuous measurements of tropospheric molecular hydrogen (H2), carbon monoxide (CO), and radon‐222 (222Rn) have been performed at Gif‐sur‐Yvette (Paris region), a suburban atmospheric measurement site in France. Molecular hydrogen mixing ratios range from 500 to 1000 ppb, CO mixing ratios vary from 100 to 1400 ppb, and 222Rn concentrations fluctuate from 0 to 20 Bq m−3. The H2 seasonal cycle shows the expected pattern for the Northern Hemisphere with a maximum in spring and a minimum in autumn. We inferred a mean baseline value of 533 ppb with a peak‐to‐peak amplitude of 30 ppb. Carbon monoxide exhibits a seasonal cycle with a maximum in winter and a minimum in summer. The mean baseline value reaches 132 ppb with a peak‐to‐peak amplitude of 40 ppb. Radon‐222 presents weak seasonal variations with a maximum in autumn/winter and a minimum in spring/summer. The diurnal cycles of H2 and CO are dominated by emissions from nearby traffic with two peaks during morning and evening rush hours. The typical H2/CO emission ratio from traffic is found to be 0.47 ± 0.08 on a molar basis (ppb/ppb). The radon tracer method is applied to nighttime H2 observations to estimate the H2 soil uptake of the nocturnal catchment area of our sampling site. The influences from nocturnal local anthropogenic combustion sources are estimated by parallel measurements of CO at 0.14 × 10−5 g(H2) m−2 h−1. The mean inferred dry deposition velocity is 0.024 ± 0.013 cm s−1 with a seasonal amplitude of 40% at Gif‐sur‐Yvette.
Importance of biomass in the global carbon cycle
Authors: Houghton R. A. , Hall Forrest , Goetz Scott J.
Published: September 2009

Our knowledge of the distribution and amount of terrestrial biomass is based almost entirely on ground measurements over an extremely small, and possibly biased sample, with many regions still unmeasured. Our understanding of changes in terrestrial biomass is even more rudimentary, although changes in land use, largely tropical deforestation, are estimated to have reduced biomass, globally. At the same time, however, the global carbon balance requires that terrestrial carbon storage has increased, albeit the exact magnitude, location, and causes of this residual terrestrial sink are still not well quantified. A satellite mission capable of measuring aboveground woody biomass could help reduce these uncertainties by delivering three products. First, a global map of aboveground woody biomass density would halve the uncertainty of estimated carbon emissions from land use change. Second, an annual, global map of natural disturbances could define the unknown but potentially large proportion of the residual terrestrial sink attributable to biomass recovery from such disturbances. Third, direct measurement of changes in aboveground biomass density (without classification of land cover or carbon modeling) would indicate the magnitude and distribution of at least the largest carbon sources (from deforestation and degradation) and sinks (from woody growth). The information would increase our understanding of the carbon cycle, including better information on the magnitude, location, and mechanisms responsible for terrestrial sources and sinks of carbon. This paper lays out the accuracy, spatial resolution, and coverage required for a satellite mission that would generate these products.
Diachronous benthic δ18O responses during late Pleistocene terminations
Authors: Lisiecki Lorraine E. , Raymo Maureen E.
Published: September 2009

Benthic δ18O is often used as a stratigraphic tool to place marine records on a common age model and as a proxy for the timing of ice volume/sea level change. However, Skinner and Shackleton (2005) found that the timing of benthic δ18O change at the last termination differed by 3900 years between one Atlantic site and one Pacific site. These results suggest that benthic δ18O change may not always accurately record the timing of deglaciation. We compare benthic δ18O records from 20 Atlantic sites and 14 Pacific sites to evaluate systematic differences in the timing of terminations in benthic δ18O. Analysis of sedimentation rates derived from the alignment of benthic δ18O suggests a statistically significant Atlantic lead over Pacific benthic δ18O change during the last six terminations. We estimate an average Pacific benthic δ18O lag of 1600 years for Terminations 1–5, slightly larger than the delay expected from ocean mixing rates given that most glacial meltwater probably enters the North Atlantic. We additionally find evidence of ∼4000‐year Pacific δ18O lags at approximately 128 ka and 330 ka, suggesting that stratigraphic correlation of δ18O has the potential to generate age model errors of several thousand years during terminations. A simple model demonstrates that these lags can be generated by diachronous temperature changes and do not require slower circulation rates. Most importantly, diachronous benthic δ18O responses must be taken into account when comparing Atlantic and Pacific benthic δ18O records or when using benthic δ18O records as a proxy for the timing of ice volume change.
Convergent evolution of coenzyme M biosynthesis in the Methanosarcinales: cysteate synthase evolved from an ancestral threonine synthase
Authors: Graham David E. , Taylor Stephanie M. , Wolf Rachel Z. , Namboori Seema C.
Published: September 2009

The euryarchaeon Methanosarcina acetivorans has no homologues of the first three enzymes that produce the essential methanogenic coenzyme M (2-mercaptoethanesulfonate) in Methanocaldococcus jannaschii. A single M. acetivorans gene was heterologously expressed to produce a functional sulfopyruvate decarboxylase protein, the fourth canonical enzyme in this biosynthetic pathway. An adjacent gene, at locus MA3297, encodes one of the organism's two threonine synthase homologues. When both paralogues from this organism were expressed in an Escherichia coli threonine synthase mutant, the MA1610 gene complemented the thrC mutation, whereas the MA3297 gene did not. Both PLP (pyridoxal 5′-phosphate)-dependent proteins were heterologously expressed and purified, but only the MA1610 protein catalysed the canonical threonine synthase reaction. The MA3297 protein specifically catalysed a new β-replacement reaction that converted L-phosphoserine and sulfite into L-cysteate and inorganic phosphate. This oxygen-independent mode of sulfonate biosynthesis exploits the facile nucleophilic addition of sulfite to an α,β-unsaturated intermediate (PLP-bound dehydroalanine). An amino acid sequence comparison indicates that cysteate synthase evolved from an ancestral threonine synthase through gene duplication, and the remodelling of active site loop regions by amino acid insertion and substitutions. The cysteate product can be converted into sulfopyruvate by an aspartate aminotransferase enzyme, establishing a new convergent pathway for coenzyme M biosynthesis that appears to function in members of the orders Methanosarcinales and Methanomicrobiales. These differences in coenzyme M biosynthesis afford the opportunity to develop methanogen inhibitors that discriminate between the classes of methanogenic archaea.
Carbon monoxide and nitric oxide modulate hyperosmolality-induced oxytocin secretion by the hypothalamusin vitro
Authors: Gomes Dayane Aparecida , Giusti-Paiva Alexandre , Ventura Renato Rizo , Elias Lucila Leico Kagohara , Cunha Fernando Queiroz , Antunes-Rodrigues Jose
Published: September 2009

OT (oxytocin) is secreted from the posterior pituitary gland, and its secretion has been shown to be modulated by NO (nitric oxide). In rats, OT secretion is also stimulated by hyperosmolarity of the extracellular fluid. Furthermore, NOS (nitric oxide synthase) is located in hypothalamic areas involved in fluid balance control. In the present study, we evaluated the role of the NOS/NO and HO (haem oxygenase)/CO (carbon monoxide) systems in the osmotic regulation of OT release from rat hypothalamus in vitro. We conducted experiments on hypothalamic fragments to determine the following: (i) whether NO donors and NOS inhibitors modulate OT release and (ii) whether the changes in OT response occur concurrently with changes in NOS or HO activity in the hypothalamus. Hyperosmotic stimulation induced a significant increase in OT release that was associated with a reduction in nitrite production. Osmotic stimulation of OT release was inhibited by NO donors. NOS inhibitors did not affect either basal or osmotically stimulated OT release. Blockade of HO inhibited both basal and osmotically stimulated OT release, and induced a marked increase in NOS activity. These results indicate the involvement of CO in the regulation of NOS activity. The present data demonstrate that hypothalamic OT release induced by osmotic stimuli is modulated, at least in part, by interactions between NO and CO.
How and why does the endoplasmic reticulum move?
Authors: Bola Becky , Allan Viki
Published: September 2009

The ER (endoplasmic reticulum) is a fascinating organelle that is highly dynamic, undergoing constant movement and reorganization. It has many key roles, including protein synthesis, folding and trafficking, calcium homoeostasis and lipid synthesis. It can expand in size when needed, and the balance between tubular and lamellar regions can be altered. The distribution and organization of the ER depends on both motile and static interactions with microtubules and the actin cytoskeleton. In the present paper, we review how the ER moves, and consider why this movement may be important for ER and cellular function.
Structural basis of EB1 effects on microtubule dynamics
Authors: Coquelle Frédéric M. , Vitre Benjamin , Arnal Isabelle
Published: September 2009

+TIPs (plus-end tracking proteins) are an increasing group of molecules that localize preferentially to the end of growing microtubules. +TIPs regulate microtubule dynamics and contribute to the organization of the microtubular network within the cell. Thus they participate in a wide range of cellular processes including cell division, motility and morphogenesis. EB1 (end-binding 1) is a highly conserved key member of the +TIP group that has been shown to modulate microtubule dynamics both in vitro and in cells. EB1 is involved in accurate chromosome segregation during mitosis and in the polarization of the microtubule cytoskeleton in migrating cells. Here, we review recent in vitro studies that have started to reveal a regulating activity of EB1, and its yeast orthologue Mal3p, on microtubule structure. In particular, we examine how EB1-mediated changes in the microtubule architecture may explain its effects on microtubule dynamics.
Regulation of microtubule dynamic instability
Authors: Vaart Babet van der , Akhmanova Anna , Straube Anne
Published: September 2009

Proper regulation of MT (microtubule) dynamics is essential for various vital processes, including the segregation of chromosomes, directional cell migration and differentiation. MT assembly and disassembly is modulated by a complex network of intracellular factors that co-operate or antagonize each other, are highly regulated in space and time and are thus attuned to the cell cycle and differentiation processes. While we only begin to appreciate how the concerted action of MT stabilizers and destabilizers shapes different MT patterns, a clear picture of how individual factors affect the MT structure is emerging. In this paper, we review the current knowledge about proteins that modulate MT dynamic instability.
The ‘super-resolution’ revolution
Authors: Davis Ilan
Published: September 2009

We are currently in the midst of an exciting revolution in microscopy. In many ways, this has been happening for several decades, but it is the rate of development of new methods that has increased recently. The last few years have seen an impressive proliferation of new instruments for imaging at higher resolution, imaging single molecules and faster and more sensitive multidimensional live cell imaging. These include light sheet microscopy, stimulated emission depletion, structured illumination and live cell imaging on the OMX (optical microscopy experimental) platform. However, new probes and image analysis methods have also been crucial for the development of these revolutionary methods.
Lipid order and molecular assemblies in the plasma membrane of eukaryotic cells
Authors: Cebecauer Marek , Owen Dylan M. , Markiewicz Anna , Magee Anthony I.
Published: September 2009

Multimolecular assemblies on the plasma membrane exhibit dynamic nature and are often generated during the activation of eukaryotic cells. The role of lipids and their physical properties in helping to control the existence of these structures is discussed. Technological improvements for live cell imaging of membrane components are also reviewed.
Neural network dysfunction in bipolar depression: clues from the efficacy of lamotrigine
Authors: Large Charles H. , Daniel Elena Di , Li Xingbao , George Mark S.
Published: September 2009

One strategy to understand bipolar disorder is to study the mechanism of action of mood-stabilizing drugs, such as valproic acid and lithium. This approach has implicated a number of intracellular signalling elements, such as GSK3β (glycogen synthase kinase 3β), ERK (extracellular-signal-regulated kinase)/MAPK (mitogen-activated protein kinase) or protein kinase C. However, lamotrigine does not seem to modulate any of these targets, which is intriguing given that its profile in the clinic differs from that of valproic acid or lithium, with greater efficacy to prevent episodes of depression than mania. The primary target of lamotrigine is the voltage-gated sodium channel, but it is unclear why inhibition of these channels might confer antidepressant efficacy. In healthy volunteers, we found that lamotrigine had a facilitatory effect on the BOLD (blood-oxygen-level-dependent) response to TMS (transcranial magnetic stimulation) of the prefrontal cortex. This effect was in contrast with an inhibitory effect of lamotrigine when TMS was applied over the motor cortex. In a follow-up study, a similar prefrontal specific facilitatory effect was observed in a larger cohort of healthy subjects, whereas valproic acid inhibited motor and prefrontal cortical TMS-induced BOLD response. In vitro, we found that lamotrigine (3–10 μM) enhanced the power of gamma frequency network oscillations induced by kainic acid in the rat hippocampus, an effect that was not observed with valproic acid (100 μM). These data suggest that lamotrigine has a positive effect on corticolimbic network function that may differentiate it from other mood stabilizers. The results are also consistent with the notion of corticolimbic network dysfunction in bipolar disorder.
The role of lithium in modulation of brain genes: relevance for aetiology and treatment of bipolar disorder
Authors: Fatemi S. Hossein , Reutiman Teri J. , Folsom Timothy D.
Published: September 2009

Bipolar disorder is a debilitating disorder of the brain with a lifetime prevalence of 1.0% for bipolar I, 1.1% for bipolar II disorder and 2.4–4.7% for subthreshold bipolar disorder. Medications, including lithium, have demonstrated efficacy in the treatment of bipolar disorder, but their molecular targets and mode of action are largely unknown. A few studies have begun to shed light on potential targets of lithium treatment that may be involved in lithium's therapeutic effect. We have recently conducted a microarray study of rat frontal cortex following chronic treatment (21 days) with lithium. Chronic treatment with lithium led to a significant (at least 1.5-fold) down-regulation of 151 genes and up-regulation of 57 genes. We discuss our results in the context of previous microarray studies involving lithium and gene-association studies to identify key genes associated with chronic lithium treatment. A number of genes associated with bipolar disorder, including Comt (catechol-O-methyltransferase), Vapa (vesicle-associated membrane protein-associated protein A), Dtnb (dystrobrevin β) and Pkd1 (polycystic kidney disease 1), were significantly altered in our microarray dataset along with genes associated with synaptic transmission, apoptosis and transport among other functions.
Cellular consequences of inositol depletion
Authors: Deranieh Rania M. , Greenberg Miriam L.
Published: September 2009

The inositol-depletion hypothesis was suggested to explain the therapeutic mechanism of mood-stabilizing drugs. Focus was previously on the phosphatidylinositol signalling pathway and on the regulatory roles of Ins(3,4,5)P3 and DAG (diacylglycerol). Recent findings indicate that inositol and inositol-containing molecules, including phosphoinositides and inositol phosphates, have signalling and regulatory roles in many cellular processes. This suggests that depleting inositol may lead to perturbation of a wide range of cellular functions, at least some of which may be associated with bipolar disorder.
Termination of tyrphostin AG1478 application results in different recovery of EGF receptor tyrosine residues 1045 and 1173 phosphorylation in A431 cells
Authors: Kondratov Kirill A. , Chernorudskiy Alexander L. , Amosova Alina P. , Kornilova Elena S.
Published: September 2009

Tyrphostin AG1478 is known as a specific and reversible inhibitor of TK (tyrosine kinase) activity of the EGFR [EGF (epidermal growth factor) receptor]. It is attractive as an anticancer agent for cancers with elevated EGFR TK levels. However, post‐application effects of AG1478 are not well studied. We have analysed EGFR phosphorylation after termination of AG1478 application using human epidermoid carcinoma A431 cells. It was found that AG1478 inhibitory action is fast, but not fully reversible: removal of tyrphostin resulted in incomplete restoration of the overall EGFR phosphorylation. Analysing the state of two individual autophosphorylation sites of internalized EGFR, Tyr1045 and Tyr1173, we demonstrated that phosphorylation of Tyr1173 involved in stimulation of the MAPK (mitogen‐activated protein kinase) cascade was restored much more efficiently than that in position 1045, which binds the ubiquitin ligase c‐Cbl and is necessary for targeting the receptor for lysosomal degradation. c‐Cbl association with EGFR abolished by AG1478 was not reestablished after tyrphostin cessation. As a consequence, ubiquitination‐dependent EGFR delivery to lysosomes was blocked, while phosphorylation of ERK1/2 (extracellular‐signal‐regulated kinase 1/2) was even increased. Thus, after termination of AG1478, the intracellular level of the inhibitor can be reached at which mitogenic signalling will be restored, whereas the EGFR negative regulation due to lysosomal degradation will not.
A simple sequential-binding model for calcium puffs
Authors: Swaminathan D. , Ullah G. , Jung P.
Published: September 2009

Calcium puffs describe the transient release of Ca2+ ions into the cytosol, through small clusters of 1,4,5-inositol triphosphate (IP3) receptors, present on internal stores such as the endoplasmic reticulum. Statistical properties of puffs, such as puff amplitudes and durations, have been well characterized experimentally. We model calcium puffs using a simple, sequential-binding model for the IP3 receptor in conjunction with a computationally inexpensive point-source approximation. We follow two different protocols, a sequential protocol and a renewal protocol. In the sequential protocol, puffs are generated successively by the same cluster; in the renewal protocol, the system is reset after each puff. In both cases for a single set of parameters our results are in excellent agreement with experimental results for puff amplitudes and durations but indicate puff-to-puff correlations for the sequential protocol, consistent with recent experimental findings [H. J. Rose, S. Dargan, J. W. Shuai, and I. Parker, Biophys. J. 91, 4024 (2006)]. The model is then used to test the consistency of the hypothesized steep Ca2+ gradients around single channels with the experimentally observed features of puff durations and amplitudes. A three-dimensional implementation of our point-source model suggests that a peak Ca2+ concentration of the order of 10 μM at the cluster site (not channel) is consistent with the statistical features of observed calcium puffs.
Energy partitioning and impulse dispersion in the decorated, tapered, strongly nonlinear granular alignment: A system with many potential applications
Authors: Doney Robert L. , Agui Juan H. , Sen Surajit
Published: September 2009

Rapid absorption of impulses using light-weight, small, reusable systems is a challenging problem. An axially aligned set of progressively shrinking elastic spheres, a “tapered chain,” has been shown to be a versatile and scalable shock absorber in earlier simulational, theoretical, and experimental works by several authors. We have recently shown (see R. L. Doney and S. Sen, Phys. Rev. Lett. 97, 155502 (2006)) that the shock absorption ability of a tapered chain can be dramatically enhanced by placing small interstitial grains between the regular grains in the tapered chain systems. Here we focus on a detailed study of the problem introduced in the above mentioned letter, present extensive dynamical simulations using parameters for a titanium-aluminum-vanadium alloy Ti6Al4V, derive attendant hard-sphere analyses based formulae to describe energy dispersion, and finally discuss some preliminary experimental results using systems with chrome spheres and small Nitinol interstitial grains to present the underlying nonlinear dynamics of this so-called decorated tapered granular alignment. We are specifically interested in small systems, comprised of several grains. This is because in real applications, mass and volume occupied must inevitably be minimized. Our conclusion is that the decorated tapered chain offers enhanced energy dispersion by locking in much of the input energy in the grains of the tapered chain rather than in the small interstitial grains. Thus, the present study offers insights into how the shock absorption capabilities of these systems can be pushed even further by improving energy absorption capabilities of the larger grains in the tapered chains. We envision that these scalable, decorated tapered chains may be used as shock absorbing components in body armor, armored vehicles, building applications and in perhaps even in applications in rehabilitation science.
Current-voltage characteristics of metal-oxide-semiconductor devices containing Ge or Si nanocrystals in thin gate oxides
Authors: Beyer V. , von Borany J. , Klimenkov M. , Müller T.
Published: September 2009

Current-voltage characteristics were measured, electrically modeled, and calculated for gate oxides, which contain nanocrystals (NCs) in different distributions, sizes, and densities. Ge and Si NCs were synthesized embedded in separate thin SiO2 layers by ion implantation at different fluences and subsequent annealing. It was found that the currents through the NC containing thin gate oxides are strongly related to the NCs’ location and are not driven by ion implantation induced oxide defects. Charging of the NCs determines the internal electrical fields, which is confirmed by simultaneous current and capacitance measurements. Depending on the implanted fluence the Ge NCs were mainly detected in the oxide center or close to the Si/SiO2 interface. The Si NCs were fabricated in the oxide center sandwiched between two oxide regions denuded of NCs. The processes of Si NC formation, growth and dissolution are discussed by means of kinetic lattice Monte Carlo simulations.
Optimization of (Gd)5Si4 based materials: A step toward self-controlled hyperthermia applications
Authors: Ahmad S. N. , Shaheen S. A.
Published: September 2009

Structural and magnetic properties have been studied across the Gd5(Si1−xGex)4 and (Gd1−xRx)5Si4 series, with R=Ce Nd, Er, and Ho, in the context of their use as ferromagnetic materials in the self-controlled hyperthermia treatment of cancer. The study shows that these materials have high magnetization values and their magnetic ordering temperatures (TC) can be varied linearly over a broad range by adjusting the composition of the constituent elements. The magnetization values of these materials are close to the bulk value of α-Fe and are substantially higher than other transition metal and Fe based magnetic materials, e.g., oxide and ferrites. The high magnetization and optimality of TC values for self-controlled hyperthermia applications observed in these materials distinguish them as magnetic material of choice for such applications.
Calculation of the capacitances of conductors: Perspectives for the optimization of electronic devices
Authors: Kopp Thilo , Mannhart Jochen
Published: September 2009

The equation describing the capacitance of capacitors is determined. It is shown that by optimizing the material of the conducting electrodes, the capacitance of capacitors reaching the quantum regime can be substantially enhanced or reduced. Dielectric capacitors with negative total capacitances are suggested and their properties analyzed. Resulting perspectives to enhance the performance of electronic devices are discussed.
Numerical simulation and experimentation of a novel laser indirect shock forming
Authors: Liu Huixia , Shen Zongbao , Wang Xiao , Wang Hejun
Published: September 2009

A novel laser indirect shock forming is presented, which uses laser-driven flyer to load the workpiece. Experiments were performed by allowing the laser-driven flyer to impact a stationary workpiece. The flyer can protect the workpiece from thermal effects so that pure mechanical effects are induced. The experimental results show that laser indirect shock forming is possible and the workpiece have a high spatial resolution at the micron level. In addition, the forming technology can effectively prevent wrinkling. The effect of laser energies on the deformation mechanism was investigated experimentally, and experimental data obtained were then used to validate the corresponding simulation model. The results show that the finite element analysis can predict the final shape of workpiece properly.
Robust and efficient density fitting
Authors: Domínguez-Soria Víctor D. , Geudtner Gerald , Morales José Luis , Calaminici Patrizia , Köster Andreas M.
Published: September 2009

In this paper we propose an iterative method for solving the inhomogeneous systems of linear equations associated with density fitting. The proposed method is based on a version of the conjugate gradient method that makes use of automatically built quasi-Newton preconditioners. The paper gives a detailed description of a parallel implementation of the new method. The computational performance of the new algorithms is analyzed by benchmark calculations on systems with up to about 35 000 auxiliary functions. Comparisons with the standard, direct approach show no significant differences in the computed solutions.
A study of plasmonics in metallic photonic quantum wires
Authors: Singh Mahi R.
Published: September 2009

The effect of plasmons on the bound photon modes has been studied in metallic photonic quantum nanowires. Nanowires are made from a metallic photonic crystal and a dielectric photonic crystal where the former is embedded into the latter. Photons are localized within the metallic crystal and are reflected from the dielectric crystal. The nanowire is doped with nanoparticles, which are interacting with the localized photons. It is found that number of bound photons states within the wire depends on the plasmon frequency. The bound photon energy decreases as the plasmon energy increases. Numerical simulations of the absorption coefficient predict that the position of a transparent state can be switched by changing the frequency of plasmons. The present study can be used to make new types of optoelectronic devices.
On the analogy between streamlined magnetic and solid obstacles
Authors: Votyakov E. V. , Kassinos S. C.
Published: September 2009

Analogies are elaborated in the qualitative description of two systems: the magnetohydrodynamic (MHD) flow moving through a region where an external local magnetic field (magnetic obstacle) is applied and the ordinary hydrodynamic flow around a solid obstacle. The former problem is of interest both practically and theoretically, and the latter one is a classical problem being well understood in ordinary hydrodynamics. The first analogy is the formation in the MHD flow of an impenetrable region—core of the magnetic obstacle—as the interaction parameter N, i.e., strength of the applied magnetic field, increases significantly. The core of the magnetic obstacle is streamlined both by the upstream flow and by the induced cross-stream electric currents, such as a foreign insulated insertion placed inside the ordinary hydrodynamic flow. In the core, closed streamlines of the mass flow resemble contour lines of electric potential, while closed streamlines of the electric current resemble contour lines of pressure. The second analogy is the breaking away of attached vortices from the recirculation pattern produced by the magnetic obstacle when the Reynolds number Re, i.e., velocity of the upstream flow, is larger than a critical value. This breaking away of vortices from the magnetic obstacle is similar to that occurring past a solid obstacle. Depending on the inlet and/or initial conditions, the observed vortex shedding can be either symmetric or asymmetric.
Kinetic dispersion of Langmuir waves. I. The Langmuir decay instability
Authors: Palastro J. P. , Williams E. A. , Hinkel D. E. , Divol L. , Strozzi D. J.
Published: September 2009

We derive a fully kinetic, three-dimensional dispersion relation for Langmuir waves with a focus on the Langmuir decay instability (LDI). The kinetic dispersion is compared to the standard fluid dispersion found with an equation of state (EOS) closure. The EOS closure fails to capture the intricacies of the nonlinear pressure when high frequency electron plasma waves (EPWs) couple to low frequency ion acoustic waves (IAWs). In particular, we find discrepancies in the kλd scaling of the LDI growth rate, where k is the wavenumber of the incident EPW and λd is the Debye length. As a result, the kinetic dispersion relation for LDI results in instability thresholds that can be in excess of twice those predicted by the fluid theory. Both the fluid and kinetic dispersion relations predict a nonlinear frequency shift due to the beating of the pump and scattered EPWs, but again the kλd scaling of these frequency shifts differ. In addition, the kinetic dispersion predicts a nonlinear reduction in the IAW damping from the three-wave interaction.
Observation of polarization-gate based reconstruction quality improvement during the process of turbidity suppression by optical phase conjugation
Authors: Cui Meng , McDowell Emily J. , Yang Changhuei
Published: September 2009

We present experiments that study the impact of polarization selection on the phenomenon of turbidity suppression by optical phase conjugation. Counter to intuition, we discovered that the preferential utilization of multiply scattered light field components over their sparsely scattered counterparts via appropriate polarization selection can lead to better image reconstruction quality. This effect was observed with tissue phantoms and biological tissue sections. The physical origin of this effect and its dependence on scatterer properties are discussed.
Assessing growth band counts from vertebrae and dorsal-fin spines for ageing sharks: comparison of four methods applied to Heterodontus portusjacksoni
Authors: Tovar-Ávila Javier , Izzo Christopher , Walker Terence I. , Braccini J. Matías , Day Robert W.
Published: September 2009

Four methods for counting growth bands using vertebrae and dorsal-fin spines of the Port Jackson shark, Heterodontus portusjacksoni, are compared. Both calcified structures presented observable growth bands, allowing cross comparison among structures for the first time in a shark species. Whole and sectioned vertebrae and dorsal fin-spines possess highly visible growth bands and intra-reader band counts resulted in similar precision indices with little systematic bias. However, inter-reader growth band count plots showed possible biases in counts from sectioned vertebrae and sectioned dorsal-fin spines. Sectioned vertebrae and whole and sectioned dorsal-fin spines produced similar growth band counts, whereas whole vertebrae produced significantly lower counts. The similar readability, precision indices, growth band counts and apparent absence of biases between counts for a single reader would indicate that sectioned vertebrae and whole and sectioned dorsal-fin spines are both potentially useful and acceptable methods for band counting. However, inter-reader comparisons are necessary to avoid acceptance of biased estimations, resulting in over- or under-estimations of age. Validation for all age classes is essential to determining accurate age estimations for this and other species.
Arsenic species in Australian temperate marine food chains
Authors: Maher W. , Foster S. , Krikowa F.
Published: September 2009

Although over 50 arsenic species have been identified in marine organisms, the biochemical pathways by which these species are formed are not known. In this paper, we present an overview of bioconversions of arsenic species that occur in marine food chains based on studies conducted by our laboratory as well as the work of others. Phytoplankton and macroalgae only contain dimethylarsenoribosides or simple methylated arsenic compounds such as dimethylarsenate and dimethylarsenoethanol. Marine animals contain mostly arsenobetaine and a range of other arsenic species that may be precursors of arsenobetaine formation. The formation of arsenobetaine in marine animals from dimethylarsenoribosides may occur through a two-stage conversion pathway: arsenoriboside or trimethylarsonioriboside degradation to arsenocholine followed by quantitative oxidation to arsenobetaine. The minor arsenic species found in marine organisms are sulfur analogues of compounds found in the S-adenosylmethionine-methionine salvage and the dimethylsulfoniopropionate metabolic pathway of animals. A key intermediate in these pathways would be arsenomethionine, which could possibly be formed from dimethylarsinite, dimethylarsenoribosides or an arsenic-containing analogue of S-adenosylmethionine. Examining arsenic species in whole ecosystems has the advantage of using the pattern of arsenic species found to postulate the biochemical pathways of their formation.