bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypoxia‐induced shifts in nitrogen and phosphorus cycling in Chesapeake Bay
Authors: Testa Jeremy Mark , Kemp W. Michael
Published: May 2012

We investigated interactions between hypoxia and nutrient cycling in Chesapeake Bay using quantitative analysis of long‐term monitoring data covering the periods 1965‐1980 and 1985‐2007. The data included vertical water column profiles of temperature, salinity, NH+4, PO3‐4, and O2, as well as rates of total nitrogen (TN) and total phosphorus (TP) loading to the bay from the Susquehanna River. We investigated the hypothesis that a doubling of the volume of hypoxic (O2 < 62.5 µmol L−1) water generated per unit TN load in the past 25 yr is related to enhanced water‐column and sediment recycling of NH+4 and PO3‐4 under low O2, and that this increased nutrient recycling creates a feedback that further generates hypoxia. We found that bottom water in the upper bay region, where seasonal hypoxia first develops, was enriched in NH+4 and PO3‐4 relative to other regions. Evidence of the positive feedback effect of low O2 on nutrient recycling was found in the fact that bottom‐water pools of NH+4 and PO3‐;4 per unit TN and TP loading, respectively, were significantly and positively related to hypoxic volume in upper bay regions during June. Similarly, NH+4 pools generated per unit TN load were significantly higher during 1985‐2007, when hypoxic volume had been approximately doubled, relative to 1965‐1980. This positive feedback effect on nutrient recycling may help to explain the persistence of extensive hypoxia in June, even during years of reduced N loading.
Benthic iron and phosphorus fluxes across the Peruvian oxygen minimum zone
Authors: Noffke A. , Hensen C. , Sommer S. , Scholz F. , Bohlen L. , Mosch T. , Graco M. , Wallmann K.
Published: May 2012

Benthic fluxes of dissolved ferrous iron (Fe2+) and phosphate (TPO4) were quantified by in situ benthic chamber incubations and pore‐water profiles along a depth transect (11°S, 80‐1000 m) across the Peruvian oxygen minimum zone (OMZ). Bottom‐water O2 levels were < 2 µmol L−1 down to 500‐m water depth, and increased to ∼ 40 µmol L−1 at 1000 m. Fe2+ fluxes were highest on the shallow shelf (maximum 316 mmol m−2 yr−1), moderate (15.4 mmol m−2 yr−1) between 250 m and 600 m, and negligible at deeper stations. In the persistent OMZ core, continuous reduction of Fe oxyhydroxides results in depletion of sedimentary Fe : Al ratios. TPO4 fluxes were high (maximum 292 mmol m−2 yr−1) throughout the shelf and the OMZ core in association with high organic carbon degradation rates. Ratios between organic carbon degradation and TPO4 flux indicate excess release of P over C when compared to Redfield stoichiometry. Most likely, this is caused by preferential P release from organic matter, dissolution of fish debris, and/or P release from microbial mat communities, while Fe oxyhydroxides can only be inferred as a major P source on the shallow shelf. The benthic fluxes presented here are among the highest reported from similar, oxygen‐depleted environments and highlight the importance of sediments underlying anoxic water bodies as nutrient sources to the ocean. The shelf is particularly important as the periodic passage of coastal trapped waves and associated bottom‐water oxygenation events can be expected to induce a transient biogeochemical environment with highly variable release of Fe2+ and TPO4.
Methanogenesis pathways in a stratified eutrophic alpine lake (Lake Bled, Slovenia)
Authors: Mandic-Mulec Ines , Gorenc Katja , Petrišiš Marinka Gams , Faganeli Jadran , Ogrinc Nives
Published: May 2012

The production pathway and carbon source of CH4 in the surface sediment of a eutrophic alpine lake (Lake Bled, northwest Slovenia), in which the hypolimnion is anoxic for most of the year, were determined from molecular and biogeochemical studies. The average δ13CCH4 value of ‐69.5‰ ± 1.2‰, associated with low acetate concentrations, suggested that CH4 should be formed, predominantly, hydrogenotrophically. The proportion of “fresh” autochthonous lipids in total extractable lipids in sediment decreased from 62% at the surface to 41% at a depth of 20 cm. The contribution of lipids of bacterial origin was more pronounced at the surface, comprising 13%. Terminal restriction fragment length polymorphism (T‐RFLP) analysis of 16S ribosomal ribonucleic acid (rRNA) sequences of bacterial and archaeal community members suggested that larger sediment‐depth‐dependent changes occurred in the latter. The majority of archaeal sequences belonged to Euryarchaeota. The methanogenic population accounted for 73% and 38% of the archaeal community at depths of 0‐2 cm and 10‐12 cm, respectively. In the upper 2 cm, hydrogenotrophs, mostly Methanomicrobiaceae, were dominant. In the deeper sediment, archaeal sequences were mostly those of unknown affiliation with Euryarchaeota, Thermoplasmatales, and related linkages, and only 21% of the hydrogenotrophic methanogenic archaea were detected. Somewhat lower percentages (< 18%) of sequences representing acetotrophic archaea (Methanosaetaceae) were present in the two layers. The biogeochemical processes and structure of the archaeal community support the hypothesis that hydrogenotrophic methanogenesis is the dominant pathway in the sediment of alpine Lake Bled, despite low temperature and the prevalence of “fresh” autochthonous‐derived organic matter.
Controls on solute transport in large spring‐fed karst rivers
Authors: Hensley Robert T. , Cohen Matthew J.
Published: May 2012

The spring‐fed rivers of North Florida flow across a karst plain, leading us to predict significant hyporheic transient storage within the secondary porosity of the carbonate media. They also span a gradient of submerged macrophyte cover and density, offering an opportunity to investigate reach‐scale vegetation effects on dispersion and transient storage. Conservative tracer tests using Rhodamine WT were conducted on nine rivers spanning the extant range of vegetative and geomorphologic characteristics. A one‐dimensional advection‐dispersion‐storage model with variable configurations of storage zones was fit to tracer breakthrough curves to determine optimal model coefficients as well as storage‐zone configuration (i.e., single, two in parallel, two in series). In most cases, two zones in series best fit the observed breakthrough curves. Moreover, fitted storage‐zone attributes were significantly correlated across springs with field‐measured analogs (i.e., vegetation area for storage zone 1, sediment area for zone 2), supporting inference that this model configuration physically represents the river systems. While the hyporheic zone area was large, its effect on transient storage was not, presumably because low‐hydraulic‐conductivity sediments and weak hydraulic gradients limit exchange with the secondary porosity of karst matrix; tracer mass recovery uniformly near 100% underscores the absence of significant hydraulic turnover. Vegetation was a significant predictor of transient storage, mean velocity, and mean residence time, suggesting that plant beds exert important controls on reach‐scale hydraulics in these systems.
Partitioning whole‐lake denitrification using in situ dinitrogen gas accumulation and intact sediment core experiments
Authors: Grantz Erin M. , Kogo Aki , Scott J. Thad
Published: May 2012

We measured in situ hypolimnion and metalimnion dinitrogen (N2) accumulation rates and N2 production from sediments in contact with the reservoir epilimnia for 3 small (< 1 km2) and shallow reservoirs with inherently low stratification stability. Hypolimnion areal denitrification rates ranged from 98.6 to 168 µmol N2‐N m−2 h−1, while metalimnion rates were up to two times greater. A laboratory experiment simulating the temporary breakdown and reestablishment of the oxycline confirmed that short‐term metalimnetic denitrification could be important in reactive nitrogen (N) loss in these reservoirs. Net denitrification occurred in sediments in contact with reservoir epilimnia during seasonal mixing, but net N2 fixation occurred in these sediments during stratification. The observed shift between net denitrification and net N2 fixation in epilimnetic sediments corresponded with an annual cycle of nitrate availability in the epilimnia. Annual whole‐reservoir denitrification rates ranged from 12 to 23 g N m−2 yr−1. The hypolimnion contribution to annual denitrification was 16‐25%. Sediments in contact with epilimnia were the greatest N2 source in all of the reservoirs. However, denitrification in the anoxic metalimnion was of similar magnitude to denitrification in epilimnetic sediments at one reservoir, and variability in metalimnetic denitrification rates was related to the strength of stratification stability. Integrating habitat‐specific measurements into whole‐lake denitrification rates showed that hydrologically dynamic habitats represent important denitrification hotspots, and that periodic disturbances fuel hot moments for denitrification.
Flocs, flows, and mechanisms decoupling larval supply from settlement
Authors: Zimmer Cheryl Ann , Starczak Victoria R. , Zimmer Richard K.
Published: May 2012

Larval supply, settlement (24 h), and recruitment were measured simultaneously with flow and flocculated particulates (flocs) in a muddy, coastal embayment. Fortuitous observations indicated that flocs drifting above the bed touched down at slack tide. Unexpectedly, results showed that larval supply did not portend settlement for the two most abundant polychaetes, Mediomastus ambiseta (resident mud dweller) and Sabellaria vulgaris (nonresident sand dweller). Both variables fluctuated widely and were decoupled. Colonization of mud vs. sand trays was not significantly different, also due to high variances. A statistical power analysis indicated that resolving selectivity would require 45 (median) paired, replicate treatments. Time series of near‐bed planktonic larvae showed sizeable and sporadic spikes. Even 24‐h means failed to predict settlement. Sabellaria was numerous in zooplankton pump collections, rare in trays, and nonexistent in ambient sediments. In contrast, Mediomastus was absent from pump samples, but dominated mud trays and bottom cores. Floc contents, however, lend insight into these distributions. Densities (of order 105 m−3) of Sabellaria and Mediomastus in flocs greatly exceeded those in tray and pump samples (of order 103 m−3). Located between the water column and seafloor, organic‐rich flocs may offer transient larvae food, shelter, transport, and perusal of settlement sites. When aggregates touch down, entrained Mediomastus might exit upon contact with suitable ambient sediments, whereas nonresident Sabellaria remain suspended. Flocs may thus play a critical role in shaping connectivity and structuring species distributions.
A Fourier transform infrared trace gas analyser for atmospheric applications
Authors: Griffith D. W. T. , Deutscher N. M. , Caldow C. G. R. , Kettlewell G. , Riggenbach M. , Hammer S.
Published: May 2012

Abstract. Concern in recent decades about human impacts on Earth's climate has led to the need for improved and expanded measurement capabilities for greenhouse gases in the atmosphere. In this paper we describe in detail an in situ trace gas analyser based on Fourier Transform Infrared (FTIR) spectroscopy that is capable of simultaneous and continuous measurements of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), nitrous oxide (N2O) and 13C in CO2 in air with high precision and accuracy. Stable water isotopes can also be measured in undried airstreams. The analyser is automated and allows unattended operation with minimal operator intervention. Precision and accuracy meet and exceed the compatibility targets set by the World Meteorological Organisation – Global Atmosphere Watch Programme for baseline measurements in the unpolluted troposphere for all species except 13C in CO2. The analyser is mobile and well suited to fixed sites, tower measurements, mobile platforms and campaign-based measurements. The isotopic specificity of the optically-based technique and analysis allows application of the analyser in isotopic tracer experiments, for example 13C in CO2 and 15N in N2O. We review a number of applications illustrating use of the analyser in clean air monitoring, micrometeorological flux and tower measurements, mobile measurements on a train, and soil flux chamber measurements.
Assessing recent measurement techniques for quantifying black carbon concentration in snow
Authors: Schwarz J. P. , Doherty S. J. , Li F. , Ruggiero S. T. , Tanner C. E. , Perring A. E. , Gao R. S. , Fahey D. W.
Published: May 2012

Abstract. We evaluate the performance of the Single Particle Soot Photometer (SP2) and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) in quantifying the concentration of refractory black carbon (BC) in snow samples. We find that the SP2 can be used to measure BC mass concentration in snow with substantially larger uncertainty (60%) than for atmospheric sampling (<30%). Achieving this level of accuracy requires careful assessment of nebulizer performance and SP2 calibration with consideration of the fact that BC in snow tends to larger sizes than typically observed in the atmosphere. Once these issues are addressed, the SP2 is able to measure the size distribution and mass concentration of BC in the snow. Laboratory comparison of the SP2 and the Integrating Sphere/Integrating Sandwich Spectrophotometer (ISSW) revealed significant biases in the estimate of BC concentration from the ISSW when test samples contained dust or non-absorbing particulates. These results suggest that current estimates of BC mass concentration in snow and ice using either the SP2 or the ISSW may be associated with significant underestimates of uncertainty.
The greenhouse gas exchange responses of methane and nitrous oxide to forest change in Europe
Authors: Gundersen P. , Christiansen J. R. , Alberti G. , Brüggemann N. , Castaldi S. , Gasche R. , Kitzler B. , Klemedtsson L. , Lobo-do-Vale R. , Moldan F. , Rütting T. , Schleppi P. , Weslien P. , Zechmeister-Boltenstern S.
Published: May 2012

Abstract. Climate change and air pollution, interact with altering forest management and land-use change to produce short and long-term changes to forest in Europe. The impact of these changes on the forest greenhouse gas (GHG) balance is currently difficult to predict. To improve the mechanistic understanding of the ongoing changes, we studied the response of GHG (N2O, CH4) exchange from forest soils at twelve experimental or natural gradient forest sites, representing anticipated future forest change. The experimental manipulations one or more per site included nitrogen (N) addition (4 sites), changes of climate (temperature, 1 site; precipitation, 2 sites), soil hydrology (3 sites), harvest intensity (1 site), wood ash fertilization (1 site), pH gradient in peat (1 site) and afforestation of cropland (1 site). In most of the investigated treatments N2O emissions increased by 7 ± 3 (range 0–30) μg N2O-N m−2 h−1 across all treatments on mineral soils, but by up to 10 times the mineral soil maximum on an acidic organic soil. Soil moisture together with mineral soil C/N ratio and pH were found to significantly influence N2O emissions across all treatments. Emissions increased with N availability and decreased with soil C/N ratio, especially in interaction with increased soil moisture. High pH reduced the formation of N2O, even under otherwise favourable soil conditions. Oxidation (uptake) of CH4 was reduced from 16 ± 2 to 4 ± 6 μg CH4-C m−2 h−1 by the investigated treatments. The CH4 exchange was significantly influenced by soil moisture and soil C/N ratio across all treatments, and CH4 emissions occurred only in wet or water-saturated conditions. For most of the investigated forest manipulations or natural gradients, the response of both N2O and CH4 fluxes was towards reducing the overall GHG forest sink. The most resilient forests were dry Mediterranean forests, as well as forests with high soil C/N ratio or high soil pH. Mitigation strategies may focus on (i) sustainable management of wet forest areas and forested peat lands, (ii) continuous forest cover management, (iii) reducing atmospheric N input and, thus, N availability, and (iv) improving neutralisation capacity of acid soils (e.g. wood ash application).
A climate-flood link for the lower Mekong River
Authors: Delgado J. M. , Merz B. , Apel H.
Published: May 2012

Abstract. The Mekong River in Southeast Asia thanks its regular annual flood to the southwest monsoon. At longer time scales, the monsoon is a spatially and temporally variable circulation, with different annual to millennial variation for different regions. In this paper, the Indian and the Western Pacific components of the monsoon were analyzed to draw a light on the interannual flood variability of the Mekong River. The focus is on the variance of flood season flows at 8 stations on the Mekong River, as well as on well-known climate indexes that reflect the dynamics of the monsoon circulation and ocean temperature anomalies. An effort was made to identify the temporal resolution that contains most of the interannual variability of both flood regime of the Mekong and monsoon intensity. We found a close connection between the Western Pacific monsoon and the discharge in Kratie and other stations in the Southern Mekong region. In the frequency domain, the interannual to decadal variance of the Mekong discharge closely follows that of the Western Pacific monsoon. More importantly, the well-known regime shift of 1976 in the North Pacific is detectable in the frequency domain for flood discharge and monsoon intensity. This suggests a relationship between Pacific sea surface temperature and monsoon variance, which is a good predictor for flood variance. This dependence influences the probability of occurrence of floods in the Mekong Delta.
Climate change, growing season water deficit and vegetation activity along the north-south transect of Eastern China from 1982 through 2006
Authors: Sun P. , Yu Z. , Liu S. , Wei X. , Wang J. , Zegre N.
Published: May 2012

Abstract. Considerable work has been done to examine the relationship between environmental constraints and vegetation activities represented by the remote sensing-based Normalized Difference Vegetation Index (NDVI). However, the relationships along either environmental or vegetation type gradients are rarely examined. The aim of this paper was to identify the vegetation types that are potentially susceptible to climate change through examining the interaction between vegetation activity and water deficit. We selected 12 major vegetation types along the north-south transect of Eastern China (NSTEC), examined their time trends from 1982 to 2006 with respect to climate change, vegetation activity and water deficit. The results showed that all vegetation types experienced warming during the study period, and the majority of them experienced precipitation decline. Warming and growing season water deficit exert counteracting controls on vegetation activity. Our study found insignificant greening trends in the northernmost cold temperate coniferous forest (CTCF), three temperate herbaceous types including the meadow steppe (TMS), grass steppe (TGS) and grassland (TG), where the growing season warming exerted more than offset effect on vegetation activity (phenology) than growing season water deficit. For the three temperate forest including the coniferous (TCF), mixed (TMF) and deciduous-broadleaved (TDBF), growing season water deficit was the main constraint on vegetation activity. Differently, the growing season browning in subtropical or tropical forests of coniferous (STCF), deciduous-broadleaved (SDBF) and evergreen-broadleaved (SEBF) and subtropical grasslands (STG) were likely attributed to decline in sunshine duration due to increased summer cloudiness. Poor water status in TDS, TG, TMS and severe drought in TGS have been identified by using growing season water deficit index (GWDI), suggested these ecosystems were subjected to severe progressing drought that may create greening trend reversal in future. The emerging water deficit in CTCF, TCF and SDBF suggested their rising susceptibility to future climate change.
Evolving Center-Vortex Loops
Authors: Moosmann Julian , Hofmann Ralf
Published: May 2012

We consider coarse-graining applied to nonselfintersecting planar centervortex loops as they emerge in the confining phase of an SU(2) Yang-Mills theory. Well-established properties of planar curve-shrinking predict that a suitably defined, geometric effective action exhibits (mean-field) critical behavior when the conformal limit of circular points is reached. This suggests the existence of an asymptotic mass gap. We demonstrate that the initially sharp mean center-of-mass position in a given ensemble of curves develops a variance under the flow as is the case for a position eigenstate in free-particle quantum mechanics under unitary time evolution. A possible application of these concepts is an approach to high- superconductivity based (a) on the nonlocal nature of the electron (1 fold selfintersecting center-vortex loop) and (b) on planar curve-shrinking flow representing the decrease in thermal noise in a cooling cuprate.
An Integrative Network Biology Approach to Evaluate the Role of Endoplasmic Reticulum Stress Response in Obese Type 2 Diabetes
Authors: Mammen Oommen Anup , Narayanan Usha , Jagannath M. R.
Published: May 2012

Extracellular/intracellular stimuli can influence eukaryotic cell function through organelles that regulate critical signaling pathways. The endoplasmic reticulum (ER), for example, impacts cellular processes including protein synthesis, folding and secretion; amino acid transport; apoptosis; cell proliferation; lipid synthesis across major cell types in response to stimuli such as accumulation of misfolded proteins and glucose deprivation. Dysregulated signaling pathways underlying the ER-mediated processes mentioned above have been linked to disease conditions such as diabetes, obesity, and Alzheimer's disease. Our current understanding, however, lacks a detailed network view that integrates organelle-mediated pathway dysregulation with cellular processes and disease pathogenesis. In this report, we introduce an integrative network biology approach that combines ER-stress response pathways with basic cellular processes using data from peer-reviewed literature. As an example, we apply our systems biology approach to study the role of ER stress in pancreatic β cells under obese diabetic conditions, generate testable hypotheses, and provide novel insights into β-cell pathogenesis.
Targeted Therapy in Ewing Sarcoma
Authors: Lissat A. , Chao M. M. , Kontny U.
Published: May 2012

Despite marked improvement in the prognosis of patients with nonmetastatic Ewing sarcoma (ES), the outcome for patients with recurrent or metastatic disease remains poor. Insight into key biologic processes in ES could provide new therapeutic targets. The particular biologic feature of ES, the fusion of the EWS gene with a member of the ETS family of genes, is present in >95% of cases. The EWS-ETS chimeric protein leads to aberrant transcription that promotes tumor initiation and propagation via prosurvival and antiapoptotic pathways. Recent research has identified cooperating mutations important for ES tumorigenesis. This paper provides a summary of the latest research in ES and discusses potential novel targets for therapy.
Bioclimatological Conditions of Hrubý Jesenik: Their Relationship with Synoptical Situations
Authors: Szarek Wojciech
Published: May 2012

The focus of this paper is the characteristics of bioclimatological conditions of one popular touristic region in Czech Republic. Biometeorological conditions of the region were described from the point of view of energy exchange between human body and atmospheric environment. Influences of meteorological agents on human organisms are presented by using two indices based on MENEX model. Indices illustrate the physiological strain and subjective thermal feeling of a person exposed to thermal environment. Obtained values of indices were compared to synoptical weather types. Comparisons were provided for the most uncomfortable conditions. Groups of synoptical weather types that occur when biometeorological conditions are very uncomfortable were found.
Assessment of Mycotoxins in Edible Tree Borne Oil Seeds (TBOS)
Authors: Singh Punam K.
Published: May 2012

Assessment of mycoflora and mycotoxins associated with Tree Borne Oil Seeds (TBOS) namely Buchanania lanzan Spreng. (chironji), Juglans regia Linn. (walnut), Prunus armeniaca Linn. (apricot) and Shorea robusta Gaertn. (sal) indicates Aspergillus flavus, A. niger and Penicillium citrinum as the most frequently occurring fungi. Significant variation in pattern of mycoflora incidence was observed in fresh & stored samples. Mycotoxin producing fungi were screened under laboratory conditions for their ability to produce mycotoxins. The percentage toxigenicity was higher in the isolates of A. flavus in comparison to other mycotoxigenic fungi. In B. lanzan, twenty six percent isolates of A. flavus were toxigenic and produced up to 26 µg/ml aflatoxin B1 in the liquid media followed by J. regia (19 µg/ml), P.armeniaca (4µg/ml) and S. robusta 3.5 µg/ml). Stored samples exhibited high concentration of aflatoxin B1 when analysed for natural occurrence of mycotoxins. Level of aflatoxin B1 recorded in P. armeniaca, S. robusta, J. regia and B. lanzan was up to 0.98 µg/g, 0.91 µg/g, 0.54 µg/g and 0.48 µg/g respectively. The level of other mycotoxins citrinin, ochratoxin and zearalenone were comparatively low. Analysis of oil extracted from fungal infected stored samples showed presence of aflatoxins in natural occurrence. Incidence of aflatoxin B1 was higher in apricot oil (up to 0.32 µg/g), up to 0.28 µg/g in chironji and walnut oil whereas in sal butter up to 0.23 µg/g. TBOS under study exhibited significant reduction in the oil seeds under study exhibited oil content during fungal infection, however, reduction was more prominent in case of A. flavus in all cases.
New insights into scaling of fat‐free mass to height across children and adults
Authors: Wang Zimian , Zhang Junyi , Ying Zhiliang , Heymsfield Steven B.
Published: May 2012

Objective:

Forbes expressed fat‐free mass (FFM, in kg) as the cube of height (H, in m): FFM = 10.3 × H3. Our objective is to examine the potential influence of gender and population ancestry on the association between FFM and height.

Methods:

This is a cross‐sectional analysis involving an existing dataset of 279 healthy subjects (155 males and 124 females) with age 5–59 years and body mass index (BMI) 14–28 kg/m2. FFM was measured by a four‐component model as the criterion.

Results:

Nonlinear regression models were fitted: FFM = 10.8 × H2.95 for the males and FFM = 10.1 × H2.90 for the females. The 95% confidence intervals for the exponential coefficients were (2.83, 3.07) for the males and (2.72, 3.08) for the females, both containing hypothesized value 3.0. Population ancestry adjustment was considered in the H‐FFM model. The coefficient of the H‐FFM model for male Asians is smaller than that for male Caucasians (P = 0.006), while there is no statistically significant difference among African‐Americans, Caucasians and Hispanics: 10.6 for the males (10.1 for Asians, 10.8 for African‐Americans, 10.7 for Caucasians and 10.4 for Hispanics) and 9.6 for the females (9.3 for Asians, 9.8 for African‐Americans, 9.6 for Caucasians and 9.5 for Hispanics). Age adjustment was unnecessary for the coefficient of the H‐FFM model.

Conclusion:

Height is the most important factor contributing to the magnitude of FFM across most of the lifespan, though both gender and ancestry effects are significant in the H‐FFM model. The proposed H‐FFM model can be further used to develop a mechanistic model to explain why population ancestry, gender and age influence the associations between BMI and %Fat. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc.
Influence of body fat and level of physical activity on rate‐pressure product at rest in preschool children
Authors: Mota Jorge , Soares‐Miranda Luísa , Silva Joana Maia E , Dos Santos Sandra Silva , Vale Susana
Published: May 2012

Objective:

The rate‐pressure product (RPP) has strong correlation with the maximal oxygen consumption and is an indicator of myocardium stress being considered as the best indirect method to measure myocardial oxygen consumption. However, to the best of our knowledge, no studies have addressed in preschool children. The aim of this study was to analyze the influence of percentage of body fat (%BF) and physical activity (PA) patterns on RPP at Rest (RPPrest) as a marker of cardiac load in Preschool children.

Methods:

The study comprised 593 preschool children aged 3–6 years‐old. Heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure were taken at rest. The RPP was then calculated. The %BF was estimated from four skinfolds thicknesses and PA was assessed during 7 consecutive days by accelerometry.

Results:

Our data showed that only %BF (P ≤ 0.001) and vigorous PA (P ≤ 0.05) contributed significantly toward RPPrest variation. However, the multivariate analysis showed that only %BF (P ≤ 0.05) had a significant influence on RPPrest variation.

Conclusion:

These findings suggest that on preschoolers there is an association between RPP at rest and %BF.Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Analysis of variability of high sensitivity C‐reactive protein in lowland ecuador reveals no evidence of chronic low‐grade inflammation
Authors: Mcdade Thomas W. , Tallman Paula S. , Madimenos Felicia C. , Liebert Melissa A. , Cepon Tara J. , Sugiyama Lawrence S. , Snodgrass James Josh
Published: May 2012

Objectives:

C‐reactive protein (CRP) is a central component of innate immune defenses, and high sensitivity CRP has emerged as an important biomarker of chronic inflammation and cardiovascular disease risk. Prior analyses of CRP variability have reported stable between‐individual differences in CRP over time, but a limitation of current knowledge is that it is based on research conducted in post‐epidemiologic transition populations.

Methods:

This study evaluated CRP variability among adults in the southeastern region of the Ecuadorian Amazon where rates of infectious diseases remain high. Blood samples were collected from 52 adults at four weekly sampling intervals and were quantified using a high‐sensitivity immunoassay.

Results:

Median CRP concentration was 0.52 mg/l. About 34.6% of participants had CRP >3 mg/l at one time point, but no individuals had CRP >3 mg/l across two or more sampling intervals, and within‐individual correlations revealed low levels of stable, between‐individual differences in CRP. The application of current guidelines for the assessment of chronic inflammation failed to detect a single case of “high risk” CRP.

Conclusions:

This study is the first to investigate CRP variability in a nonindustrialized, high infectious disease environment. It documents a pattern of variation over time that is distinct from prior research, with no evidence for chronic low‐grade inflammation. These results may have substantial implications for research on inflammation and diseases of aging globally, as well as for scientific understandings of the regulation of inflammation. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.
Acrylic hydrogels‐based biocomposites: Synthesis and characterization
Authors: Sandu Teodor , Sârbu Andrei , Constantin Floriana , Vulpe Silviu , Iovu Horia
Published: May 2012

Hydrogels based on polyacrylic and polymethacrylic acids were synthesized using two variants of redox initiating systems and three crosslinking agents in various ratios to the monomer. The chemical structure of these hydrogels was extensively studied by Fourier transform infrared (FTIR) spectrometry and Raman spectrometry. These hydrogels were also characterized by other techniques, namely thermo gravimetric analysis (TGA), differential thermal gravimetry, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The hydrogel ability to immobilize enzymes through covalent bonds was studied by FTIR and Raman spectrometry and by analyzing the SEM images before and after enzyme immobilization. The enzyme influence on the thermal behavior of the hydrogel biocomposite was investigated by DSC and TGA, too. The methacrylic acid leads to more thermo stable hydrogels formation than acrylic acid. Acrylic and methacrylic hydrogels are able to covalently immobilize enzymes. This is proved by the important changes which occur in the chemical composition, the thermal behavior and the morphology of hydrogels after immobilization stage. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Mechanical properties of epoxy composites with low content of diamond particles
Authors: Rakha Sobia A. , Khan Ramsha R. , Khurram Aqeel A. , Fayyaz A. , Zakaullah M. , Munir Arshad
Published: May 2012

Diamond‐epoxy composites reinforced with low content of submicron diamond powder 0.1, 0.4, 0.7, and 1.0 wt % were synthesized. As received diamond powder was acid treated to purify and functionalize diamond particles. Fourier Transform Infrared Spectroscopy was utilized to study the moieties attached to the diamond particles. The trace elemental analysis of impurities in diamond powder before and after acid treatment was performed using ion beam techniques. The mechanical properties of the epoxy matrix were enhanced with the addition of purified and functionalized diamond powder. The Dynamical mechanical analysis results revealed that storage modulus of the prepared composites has been increased by ∼ 100% with diamond loading of 0.7 wt %. The Vickers's hardness of the diamond‐epoxy composite was ∼ 39% higher than that of pure epoxy for the loading of 1.0 wt % diamond powder. Mechanisms responsible for the enhancement of the mechanical properties are discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Dichrometer Errors Resulting from Large Signals or Improper Modulator Phasing
Authors: Sutherland John C.
Published: May 2012

A single‐beam spectrometer equipped with a photoelastic modulator can be configured to measure a number of different parameters useful in characterizing chemical and biochemical materials including natural and magnetic circular dichroism, linear dichroism, natural and magnetic fluorescence‐detected circular dichroism, and fluorescence polarization anisotropy as well as total absorption and fluorescence. The derivations of the mathematical expressions used to extract these parameters from ultraviolet, visible, and near‐infrared light‐induced electronic signals in a dichrometer assume that the dichroic signals are sufficiently small that certain mathematical approximations will not introduce significant errors. This article quantifies errors resulting from these assumptions as a function of the magnitude of the dichroic signals. In the case of linear dichroism, improper modulator programming can result in errors greater than those resulting from the assumption of small signal size, whereas for fluorescence polarization anisotropy, improper modulator phase alone gives incorrect results. Modulator phase can also impact the values of total absorbance recorded simultaneously with linear dichroism and total fluorescence. Chirality 24:706–717, 2012. © 2012 Wiley Periodicals, Inc.†
β‐arrestin 2‐dependent activation of ERK1/2 is required for ADP‐induced paxillin phosphorylation at Ser83 and microglia chemotaxis
Authors: Lee Sang‐Hyun , Hollingsworth Ryan , Kwon Hyeok‐Yil , Lee Narae , Chung Chang Y.
Published: May 2012

Microglia play crucial roles in increased inflammation in the central nervous system upon brain injuries and diseases. Extracellular ADP has been reported to induce microglia chemotaxis and membrane ruffle formation through P2Y12 receptor. In this study, we examined the role of ERK1/2 activation in ADP‐induced microglia chemotaxis. ADP stimulation increases the phosphorylation of extracellular signal‐regulated kinase 1/2 (ERK1/2) and paxillin phosphorylation at Tyr31 and Ser83. Inhibition of ERK1/2 significantly inhibited paxillin phosphorylation at Ser83 and the retraction of membrane ruffles, causing inefficient chemotaxis. Close examination of dynamics of focal adhesion (FA) formation with green fluorescent protein‐paxillin revealed that the disassembly of FAs in U0126‐treated cells was significantly impaired. Depletion of β‐Arrestin 2 (β‐Arr2) with short hairpin RNA markedly reduced the phosphorylation of ERK1/2 and Pax/Ser83, indicating that β‐Arr2 is required for ERK1/2 activation upon ADP stimulation. A large fraction of phosphorylated ERK1/2 and β‐Arr2 were translocated and co‐localized at focal contacts in the newly forming lamellipodia. Examination of kinetics and rate constant of paxillin formation and disassembly revealed that the phosphorylation of paxillin at Tyr31 by c‐Src appears to be involved in adhesion formation upon ADP stimulation while Ser83 required for adhesion disassembly. © 2012 Wiley Periodicals, Inc.
Fingolimod—A sphingosine‐like molecule inhibits vesicle mobility and secretion in astrocytes
Authors: Trkov Saša , Stenovec Matjaž , Kreft Marko , Potokar Maja , Parpura Vladimir , Davletov Bazbek , Zorec Robert
Published: May 2012

In the brain, astrocytes signal to the neighboring cells by the release of chemical messengers (gliotransmitters) via regulated exocytosis. Recent studies uncovered a potential role of signaling lipids in modulation of exocytosis. Hence, we investigated whether sphingosine and the structural analog fingolimod/FTY720, a recently introduced therapeutic for multiple sclerosis, affect (i) intracellular vesicle mobility and (ii) vesicle cargo discharge from cultured rat astrocytes. Distinct types of vesicles, peptidergic, glutamatergic, and endosomes/lysosomes, were fluorescently prelabeled by cell transfection with plasmids encoding atrial natriuretic peptide tagged with mutant green fluorescent protein and vesicular glutamate transporter tagged with enhanced green fluorescent protein or by LysoTracker staining, respectively. The confocal and total internal reflection fluorescence microscopies were used to monitor vesicle mobility in the cytoplasm and near the basal plasma membrane, respectively. Sphingosine and FTY720, but not the membrane impermeable lipid analogs, dose‐dependently attenuated vesicle mobility in the subcellular regions studied, and significantly inhibited stimulated exocytotic peptide and glutamate release. We conclude that in astrocytes, cell permeable sphingosine‐like lipids affect regulated exocytosis by attenuating vesicle mobility, thereby preventing effective vesicle access/interaction with the plasma membrane docking/release sites. © 2012 Wiley Periodicals, Inc.
Phosphorylated olig1 localizes to the cytosol of oligodendrocytes and promotes membrane expansion and maturation
Authors: Niu Jianqin , Mei Feng , Wang Lingyun , Liu Shubao , Tian Yanping , Mo Wei , Li Hongli , Lu Q. Richard , Xiao Lan
Published: May 2012

Oligodendroglial cells undergo rapid transcriptional and dynamic morphological transformation in order to effectively myelinate neuronal axons. Olig1, a basic helix‐loop‐helix transcription factor, functions to promote the transcription of myelin‐specific genes and promotes differentiation and (re)myelination. While the role for nuclear Olig1 is well established, the function for cytoplasmic Olig1 remains uncertain. We observe that translocation of Olig1 into the cytosol highly correlates with differentiation of oligodendrocytes both invivo and invitro. By enforcing expression of a nuclear‐specific form of Olig1 into OPCs in a null‐Olig1 background, we demonstrate that nuclear Olig1 is sufficient to facilitate MBP expression, but with greatly diminished membrane volume and area. We demonstrate that serine 138 in the helix‐loop‐helix domain of Olig1 is phosphorylated and that this form resides in the cytosol. Mutating serine 138 to alanine restricts Olig1 to the nucleus, facilitating MBP expression but limiting membrane expansion. However, a serine to aspartic acid mutation results in the cytoplasmic localization of Olig1 enhancing membrane expansion. Our results suggest a novel role for a phosphorylated cytosolic Olig1 in membrane expansion and maturation of oligodendrocytes. © 2012 Wiley Periodicals, Inc.
Simulating magnetohydrodynamic natural convection flow in a horizontal cylindrical annulus using the lattice Boltzmann method
Authors: Ashorynejad Hamid Reza , Sedighi Kurosh , Farhadi Mousa , Fattahi Ehsan
Published: May 2012

A numerical study is presented about the effect of a uniform magnetic field on free convection in a horizontal cylindrical annulus using the lattice Boltzmann method. The inner and outer cylinders are maintained at uniform temperatures and it is assumed the walls are insulating with a magnetic field. Detailed numerical results of heat transfer rate, temperature, and velocity fields have been presented for Pr=0.7, Ra=103 to 5 × 104, and Ha=0 to 100. The computational results show that in a horizontal cylindrical annulus the flow and heat transfer are suppressed more effectively by a radial magnetic field. It is also found that the flow oscillations can be suppressed effectively by imposing an external radial magnetic field. The average Nusselt number increases by increasing the radius ratio while it decreases by increasing the Hartmann number. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21008
Long‐term follow‐up of cancer patients treated with gene therapy medicinal products
Authors: Galli Maria Cristina
Published: May 2012

European Union requirements are discussed for the long‐term follow‐up of advanced therapy medicinal products, as well as how they can be applied to cancer patients treated with gene therapy medicinal products in the context of clinical trials, as described in a specific guideline issued by Gene Therapy Working Party at the European Medicine Agency. Copyright © 2012 John Wiley & Sons, Ltd.
Lifshitz black holes in IIA supergravity
Authors: Barclay Luke , Gregory Ruth , Parameswaran Susha , Tasinato Gianmassimo , Zavala Ivonne
Published: May 2012

Abstract

We compute string theoretic black hole solutions having Lifshitz asymptotics with a general dynamical exponent z > 1. We start by constructing solutions in a flux compactification of six dimensional supergravity, then uplift them to massive type IIA supergravity. Alongside the Lifshitz black holes we study the simpler anti-de Sitter solutions, of which there are a 1-parameter family in this supergravity, and compare and contrast their properties. The black holes are characterized by a two-form and scalar charge, and we numerically explore their configuration space and thermodynamical aspects.
Surface-modified cobalt oxide nanoparticles: new opportunities for anti-cancer drug development
Authors: Chattopadhyay S. , Chakraborty S. P. , Laha D. , Baral R. , Pramanik P. , Roy S.
Published: May 2012

The development of smart nanoparticles that can exhibit the anti-cancer activity, introduces better efficacy and lower toxicity for treatment. The present study was aimed to evaluate the anti-cancer activity of surface functionalized CoO nanoparticles against Jurkat (T-cell lymphoma) and KB (oral carcinoma) cell lines. The nano-sized cobalt oxide nanoparticles (CoO) was prepared by thermal decomposition method followed by surface modification using phosphonomethyl iminodiacetic acid (PMIDA). The PMIDA-coated CoO nanoparticle was characterized by X-ray diffraction, dynamic light scattering, and transmission electron microscopy; and the conjugation was analyzed by Fourier transform infrared spectroscopy. The resultant nanoparticles with an average size less than 100 nm measured by dynamic light scattering and transmission electron microscopy. Cytotoxicity study, flow cytometric analysis and scanning electron micrographs have been revealed that PMIDA-coated nanoparticles significantly enhances the cellular uptake of the nanoparticle and thus facilitates apoptosis of cancer cell (Jurkat and KB). For the application of PMIDA-coated CoO nanoparticles in the medical field, doxorubicin, a potent anti-cancer drug, has been used in similar fashion in this experimental design and all these effects or patterns were observed.
The NRF2‐related interactome and regulome contain multifunctional proteins and fine‐tuned autoregulatory loops
Authors: Papp Diána , Lenti Katalin , Módos Dezső , Fazekas Dávid , Dúl Zoltán , Türei Dénes , Földvári-Nagy László , Nussinov Ruth , Csermely Péter , Korcsmáros Tamás
Published: May 2012

NRF2 is a well‐known, master transcription factor (TF) of oxidative and xenobiotic stress responses. Recent studies uncovered an even wider regulatory role of NRF2 influencing carcinogenesis, inflammation and neurodegeneration. Prompted by these advances here we present a systems‐level resource for NRF2 interactome and regulome that includes 289 protein–protein, 7469 TF–DNA and 85 miRNA interactions. As systems‐level examples of NRF2‐related signaling we identified regulatory loops of NRF2 interacting proteins (e.g., JNK1 and CBP) and a fine‐tuned regulatory system, where 35 TFs regulated by NRF2 influence 63 miRNAs that down‐regulate NRF2. The presented network and the uncovered regulatory loops may facilitate the development of efficient, NRF2‐based therapeutic agents.
Structural recognition mechanisms between human Src homology domain 3 (SH3) and ALG‐2‐interacting protein X (Alix)
Authors: Shi Xiaoli , Betzi Stephane , Lugari Adrien , Opi Sandrine , Restouin Audrey , Parrot Isabelle , Martinez Jean , Zimmermann Pascale , Lecine Patrick , Huang Mingdong , Arold Stefan T. , Collette Yves , Morelli Xavier
Published: May 2012

FynR96I

physically interacts
with NEF by
two hybrid
(
View interaction
)
P4‐ATPase ATP8A2 acts in synergy with CDC50A to enhance neurite outgrowth
Authors: Xu Qin , Yang Guo-Ying , Liu Na , Xu Peng , Chen Yue-Lei , Zhou Zheng , Luo Zhen-Ge , Ding Xiaoyan
Published: May 2012

P4‐ATPases are lipid flippases that transport phospholipids across cellular membranes, playing vital roles in cell function. In humans, the disruption of the P4‐ATPase ATP8A2 gene causes a severe neurological phenotype. Here, we found that Atp8a2 mRNA was highly expressed in PC12 cells, hippocampal neurons and the brain. Overexpression of ATP8A2 increased the length of neurite outgrowth in NGF‐induced PC12 cells and in primary cultures of rat hippocampal neurons. Inducing the loss of function of CDC50A in hippocampal neurons via RNA interference reduced neurite outgrowth, and the co‐overexpression of CDC50A and ATP8A2 in PC12 cells enhanced NGF‐induced neurite outgrowth. These results indicate that ATP8A2, acting in synergy with CDC50A, performs an important role in neurite outgrowth in neurons.
Trypanosomes contain two highly different isoforms of peroxin PEX13 involved in glycosome biogenesis
Authors: Brennand Ana , Rigden Daniel J. , Michels Paul A.M.
Published: May 2012

Pex13.1
physically interacts with
Pex13.2
by two hybrid (View interaction)
Induction of epithelial‐mesenchymal transition with O‐glycosylated oncofetal fibronectin
Authors: Ding Yao , Gelfenbeyn Kirill , Freire-de-Lima Leonardo , Handa Kazuko , Hakomori Sen-itiroh
Published: May 2012

Epithelial‐mesenchymal transition (EMT) has been shown to play a key role in embryogenesis and cancer progression. We previously found that fibronectin (FN) carrying O‐GalNAc at a specific site is selectively expressed in cancer and fetal cells/tissues, and termed oncofetal FN (onfFN). Here, we show that (i) a newly‐established monoclonal antibody against FN lacking the O‐GalNAc, termed normalFN (norFN), is useful for isolation of onfFN, (ii) onfFN, but not norFN, can induce EMT in human lung carcinoma cells, (iii) onfFN has a synergistic effect with transforming growth factor (TGF)β1 in EMT induction.