bluuebunny/crossref_metadata_2025 huggingface dataset:
Partial Redundancy of the Pattern Recognition Receptors, Scavenger Receptors, and C-Type Lectins for the Long-Term Control of Mycobacterium tuberculosis Infection
Authors: Court Nathalie , Vasseur Virginie , Vacher Rachel , Frémond Cécile , Shebzukhov Yury , Yeremeev Vladimir V. , Maillet Isabelle , Nedospasov Sergei A. , Gordon Siamon , Fallon Padraic G. , Suzuki Hiroshi , Ryffel Bernhard , Quesniaux Valérie F. J.
Published: May 2010

Mycobacterium tuberculosis is recognized by multiple pattern recognition receptors involved in innate immune defense, but their direct role in tuberculosis pathogenesis remains unknown. Beyond TLRs, scavenger receptors (SRs) and C-type lectins may play a crucial role in the sensing and signaling of pathogen motifs, as well as contribute to M. tuberculosis immune evasion. In this study, we addressed the relative role and potential redundancy of these receptors in the host response and resistance to M. tuberculosis infection using mice deficient for representative SR, C-type lectin receptor, or seven transmembrane receptor families. We show that a single deficiency in the class A SR, macrophage receptor with collagenous structure, CD36, mannose receptor, specific ICAM-3 grabbing nonintegrin-related, or F4/80 did not impair the host resistance to acute or chronic M. tuberculosis infection in terms of survival, control of bacterial clearance, lung inflammation, granuloma formation, and cytokine and chemokine expression. Double deficiency for the SRs class A SR types I and II plus CD36 or for the C-type lectins mannose receptor plus specific ICAM-3 grabbing nonintegrin-related had a limited effect on macrophage uptake of mycobacteria and TNF response and on the long-term control of M. tuberculosis infection. By contrast, mice deficient in the TNF, IL-1, or IFN-γ pathway were unable to control acute M. tuberculosis infection. In conclusion, we document a functional redundancy in the pattern recognition receptors, which might cooperate in a coordinated response to sustain the full immune control of M. tuberculosis infection, in sharp contrast with the nonredundant, essential role of the TNF, IL-1, or IFN-γ pathway for host resistance to M. tuberculosis.
Effects of Immunomodulatory Substances on Phagocytosis of A by Human Microglia
Authors: Hjorth Erik , Frenkel Dan , Weiner Howard , Schultzberg Marianne
Published: May 2010

Glial activation and increased inflammation characterize neuropathology in Alzheimer's disease (AD). The aim was to develop a model for studying phagocytosis of -amyloid (A) peptide by human microglia and to test effects thereupon by immunomodulatory substances. Human CHME3 microglia showed intracellular A colocalized with lysosome-associated membrane protein-2, indicating phagocytosis. This was increased by interferon-, and to a lesser degree with Protollin, a proteosome-based adjuvant. Secretion of brain-derived neurotrophic factor (BDNF) was decreased by A and by interferon- and interleukin-1. These cytokines, but not A, stimulated interleukin-6 release. Microglia which phagocytosed A exhibited a higher degree of expression of interleukin-1 receptor type I and inducible nitric oxide synthase. In conclusion, we show that human microglia are able to phagocytose A and that this is associated with expression of inflammatory markers. A and interferon- decreased BDNF secretion suggesting a new neuropathological role for A and the inflammation accompanying AD.
Extrema of Low Eigenvalues of the Dirichlet–Neumann Laplacian on a Disk
Authors: Legendre Eveline
Published: May 2010

We study extrema of the first and the second mixed eigenvalues of the Laplacian on the disk among some families of Dirichlet–Neumann boundary conditions. We show that the minimizer of the second eigenvalue among all mixed boundary conditions lies in a compact 1-parameter family for which an explicit description is given. Moreover, we prove that among all partitions of the boundary with bounded number of parts on which Dirichlet and Neumann conditions are imposed alternately, the first eigenvalue is maximized by the uniformly distributed partition.
BMO Functions and Carleson Measures with Values in Uniformly Convex Spaces
Authors: Ouyang Caiheng , Xu Quanhua
Published: May 2010

This paper studies the relationship between vector-valued BMO functions and the Carleson measures defined by their gradients. Let dA and dm denote Lebesgue measures on the unit disc D and the unit circle 𝕋, respectively. For 1 < q < ∞ and a Banach space B, we prove that there exists a positive constant c such that

holds for all trigonometric polynomials f with coefficients in B if and only if B admits an equivalent norm which is q-uniformly convex, where

The validity of the converse inequality is equivalent to the existence of an equivalent q-uniformly smooth norm.
Reducibility of the Principal Series for (F) over a p-adic Field
Authors: Zorn Christian
Published: May 2010

Let Gn = Spn(F) be the rank n symplectic group with entries in a nondyadic p-adic field F. We further let be the metaplectic extension of Gn by defined using the Leray cocycle. In this paper, we aim to demonstrate the complete list of reducibility points of the genuine principal series of . In most cases, we will use some techniques developed by Tadić that analyze the Jacquetmodules with respect to all of the parabolics containing a fixed Borel. The exceptional cases involve representations induced from unitary characters χ with χ2 = 1. Because such representations π are unitary, to show the irreducibility of π, it suffices to show that . We will accomplish this by examining the poles of certain intertwining operators associated to simple roots. Then some results of Shahidi and Ban decompose arbitrary intertwining operators into a composition of operators corresponding to the simple roots of . We will then be able to show that all such operators have poles at principal series representations induced from quadratic characters and therefore such operators do not extend to operators in for the π in question.
A regional high-resolution carbon flux inversion of North America for 2004
Authors: Schuh A. E. , Denning A. S. , Corbin K. D. , Baker I. T. , Uliasz M. , Parazoo N. , Andrews A. E. , Worthy D. E. J.
Published: May 2010

Abstract. Resolving the discrepancies between NEE estimates based upon (1) ground studies and (2) atmospheric inversion results, demands increasingly sophisticated techniques. In this paper we present a high-resolution inversion based upon a regional meteorology model (RAMS) and an underlying biosphere (SiB3) model, both running on an identical 40 km grid over most of North America. Current operational systems like CarbonTracker as well as many previous global inversions including the Transcom suite of inversions have utilized inversion regions formed by collapsing biome-similar grid cells into larger aggregated regions. An extreme example of this might be where corrections to NEE imposed on forested regions on the east coast of the United States might be the same as that imposed on forests on the west coast of the United States while, in reality, there likely exist subtle differences in the two areas, both natural and anthropogenic. Our current inversion framework utilizes a combination of previously employed inversion techniques while allowing carbon flux corrections to be biome independent. Temporally and spatially high-resolution results utilizing biome-independent corrections provide insight into carbon dynamics in North America. In particular, we analyze hourly CO2 mixing ratio data from a sparse network of eight towers in North America for 2004. A prior estimate of carbon fluxes due to Gross Primary Productivity (GPP) and Ecosystem Respiration (ER) is constructed from the SiB3 biosphere model on a 40 km grid. A combination of transport from the RAMS and the Parameterized Chemical Transport Model (PCTM) models is used to forge a connection between upwind biosphere fluxes and downwind observed CO2 mixing ratio data. A Kalman filter procedure is used to estimate weekly corrections to biosphere fluxes based upon observed CO2. RMSE-weighted annual NEE estimates, over an ensemble of potential inversion parameter sets, show a mean estimate 0.57 Pg/yr sink in North America. We perform the inversion with two independently derived boundary inflow conditions and calculate jackknife-based statistics to test the robustness of the model results. We then compare final results to estimates obtained from the CarbonTracker inversion system and at the Southern Great Plains flux site. Results are promising, showing the ability to correct carbon fluxes from the biosphere models over annual and seasonal time scales, as well as over the different GPP and ER components. Additionally, the correlation of an estimated sink of carbon in the South Central United States with regional anomalously high precipitation in an area of managed agricultural and forest lands provides interesting hypotheses for future work.
Spatial and temporal variability of the dimethylsulfide to chlorophyll ratio in the surface ocean: an assessment in the light of phytoplankton composition determined from space
Authors: Masotti I. , Belviso S. , Alvain S. , Johnson J. E. , Bates T. S. , Tortell P. D. , Kasamatsu N. , Mongin M. , Marandino C. A. , Saltzman E. S. , Moulin C.
Published: May 2010

Abstract. Dimethylsulfide (DMS) is biologically produced in the surface ocean and is the dominant natural source of sulfur to the atmosphere. Although DMS is an algal by-product, the ratio of DMS to chlorophyll (DMS:Chl) varies widely in the surface ocean. This is presumably because dimethylsulfoniopropionate (DMSP), the major precursor of DMS, DMSP-lyases, which catalyze the conversion of DMSP to DMS, and Chl vary as well with taxonomic composition than with the physiological state of the algal assemblage. Here we use remote sensing of Chl and phytoplankton dominance from PHYSAT with in-situ measured DMS concentrations to assess on an unprecedented spatial scale the affect of species composition on the DMS:Chl ratio in the surface ocean. Meridional distributions at 22° W in the Atlantic, and 95° W and 110° W in the Pacific, showed the same marked drop in DMS:Chl ratios near the equator, down to few mmol g−1, yet the basins exhibited different species dominance signatures. Hence, our results suggest that species composition was of secondary importance in controlling DMS and DMS:Chl variations in equatorial upwellings as well as physiological shifts in algal DMS production since mixed layer growth conditions (i.e., nutrient stress, temperature and light) were relatively homogeneous over the eastern equatorial Pacific. In the Indian sector of the Southern Ocean, warm core eddies with contrasting PHYSAT signatures displayed similar DMS levels. However, DMS:Chl ratios in eddies dominated by Synechococcus (SYN) were about 50% lower than that found in eddies showing nanoeucayotes or Phaeocystis-like signatures. DMS:Chl ratios varied with latitude in SYN dominated regions with ratios at low latitudes (away from equatorial upwellings) about twice that found at high northern and southern latitudes. This is the sole piece of coherent observations which indicates that species composition and growth conditions affect the large-scale dynamics of the DMS:Chl ratio. Overall, it appears that the DMS:Chl ratio is not consistent within specific phytoplankton groups determined from space. So DMS concentrations can not be derived from water-leaving radiance spectra obtained simultaneously from ocean color sensor measurements of Chl concentrations and dominant phytoplankton functional types. To proceed with the global investigation and better discriminate between factors affecting DMS:Chl ratios in the surface ocean, we recommend the use of PHYSAT records with higher spatial resolution in conjunction with other satellite products (e.g. particulate backscattering coefficients and indices of phytoplankton physiology and bloom status).
Analyzing the carbon dynamics in north western Portugal: calibration and application of Forest-BGC
Authors: Rodrigues M. A. , Lopes D. M. , Leite S. M. , Tabuada V. M.
Published: May 2010

Abstract. Net primary production (NPP) is an important variable that allows monitoring forestry ecosystems fixation of atmospheric Carbon. The importance of monitoring the sequestred carbon is related to the binding commitments established by the Kyoto Protocol. There are ecophysiologic models, as Forest-BGC that allow for estimating NPP. In a first stage, this study aims to analyze the climate evolution at the Vila Real administrative district during the last decades. The historical information will be observed in order to detect the past tendencies of evolution. Past will help us to predict future. In a next stage these tendencies will be used to infer the impact of these change scenarios on the net primary production of the forest ecosystems from this study area. For a parameterization and validation of the FOREST-BGC, this study was carried on based on 500 m2 sampling plots from the National Forest Inventory 2006 and are located in several County Halls of the district of Vila Real (Montalegre, Chaves, Valpaços, Boticas, Vila Pouca de Aguiar, Murça, Mondim de Basto, Alijó, Sabrosa and Vila Real). In order to quantify Biomass dinamics, we have selected 45 sampling plots: 19 from Pinus pinaster stands, 17 from Quercus pyrenaica and 10 from mixed of Quercus pyrenaica with Pinus pinaster. Adaptation strategies for climate change impacts can be proposed based on these research results.
Description and evaluation of GMXe: a new aerosol submodel for global simulations (v1)
Authors: Pringle K. J. , Tost H. , Metzger S. , Steil B. , Giannadaki D. , Nenes A. , Fountoukis C. , Stier P. , Vignati E. , Lelieveld J.
Published: May 2010

Abstract. We present a new aerosol microphysics and gas aerosol partitioning submodel (Global Modal-aerosol eXtension, GMXe) implemented within the ECHAM/MESSy Atmospheric Chemistry model (EMAC, version 1.8). The submodel is computationally efficient and is suitable for medium to long term simulations with global and regional models. The aerosol size distribution is treated using 7 log-normal modes and has the same microphysical core as the M7 submodel (Vignati et al., 2004). The main developments in this work are: (i) the extension of the aerosol emission routines and the M7 microphysics, so that an increased (and variable) number of aerosol species can be treated (new species include sodium and chloride, and potentially magnesium, calcium, and potassium), (ii) the coupling of the aerosol microphysics to a choice of treatments of gas/aerosol partitioning to allow the treatment of semi-volatile aerosol, and, (iii) the implementation and evaluation of the developed submodel within the EMAC model of atmospheric chemistry. Simulated concentrations of black carbon, particulate organic matter, dust, sea spray, sulfate and ammonium aerosol are shown to be in good agreement with observations (for all species at least 40% of modeled values are within a factor of 2 of the observations). The distribution of nitrate aerosol is compared to observations in both clean and polluted regions. Concentrations in polluted continental regions are simulated quite well, but there is a general tendency to overestimate nitrate, particularly in coastal regions (geometric mean of modelled values/geometric mean of observed data ≈2). In all regions considered more than 40% of nitrate concentrations are within a factor of two of the observations. Marine nitrate concentrations are well captured with 96% of modeled values within a factor of 2 of the observations.
Irrigation enhances precipitation at the mountains downwind
Authors: Jódar J. , Carrera J. , Cruz A.
Published: May 2010

Abstract. Atmospheric circulation models predict an irrigation-rainfall feedback. However, actual field evidences are very weak. We present strong field evidence about an increase in rainfall at the mountains located downwind of irrigated zones. We chose two regions, located in semiarid southern Spain, where irrigation started at a well defined date, and we analyzed rainfall statistics before and after the beginning of irrigation. Analyzed statistics include the variation of (1) mean rainfall Δ P, (2) ratio of monthly precipitation to annual precipitation Δ r, and (3) number of months with minimum rainfall episodes Δ Pmin after a transition period from unirrigated to irrigated conditions. All of them show statistically significant increases. Δ P and Δ r show larger and more statistically significant variations in June and July. Their variation is proportional to the mean annual water volume applied in the neighboring upwind irrigation lands. Variations in Δ Pmin are statistically significant in the whole summer. That is, the number of months with some rain displays a relevant increase after irrigation. However, increase in rainfall while statistically significant is distributed over a broad region, so that it is of little relevance from a water resources perspective. The joint increment in Δ P and Δ Pmin after the irrigation transition period denotes a net increase in the number of months having a minimum cumulated precipitation in summer.
3-D imaging of particle tracks in solid state nuclear track detectors
Authors: Wertheim D. , Gillmore G. , Brown L. , Petford N.
Published: May 2010

Abstract. It has been suggested that 3 to 5% of total lung cancer deaths in the UK may be associated with elevated radon concentration. Radon gas levels can be assessed using CR-39 plastic detectors which are often assessed by 2-D image analysis of surface images. 3-D analysis has the potential to provide information relating to the angle at which alpha particles impinge on the detector. In this study we used a "LEXT" OLS3100 confocal laser scanning microscope (Olympus Corporation, Tokyo, Japan) to image tracks on five CR-39 detectors. We were able to identify several patterns of single and coalescing tracks from 3-D visualisation. Thus this method may provide a means of detailed 3-D analysis of Solid State Nuclear Track Detectors.
Characterisation of extreme winter precipitation in Mediterranean coastal sites and associated anomalous atmospheric circulation patterns
Authors: Toreti A. , Xoplaki E. , Maraun D. , Kuglitsch F. G. , Wanner H. , Luterbacher J.
Published: May 2010

Abstract. We present an analysis of daily extreme precipitation events for the extended winter season (October–March) at 20 Mediterranean coastal sites covering the period 1950–2006. The heavy tailed behaviour of precipitation extremes and estimated return levels, including associated uncertainties, are derived applying a procedure based on the Generalized Pareto Distribution, in combination with recently developed methods. Precipitation extremes have an important contribution to make seasonal totals (approximately 60% for all series). Three stations (one in the western Mediterranean and the others in the eastern basin) have a 5-year return level above 100 mm, while the lowest value (estimated for two Italian series) is equal to 58 mm. As for the 50-year return level, an Italian station (Genoa) has the highest value of 264 mm, while the other values range from 82 to 200 mm. Furthermore, six series (from stations located in France, Italy, Greece, and Cyprus) show a significant negative tendency in the probability of observing an extreme event. The relationship between extreme precipitation events and the large scale atmospheric circulation at the upper, mid and low troposphere is investigated by using NCEP/NCAR reanalysis data. A 2-step classification procedure identifies three significant anomaly patterns both for the western-central and eastern part of the Mediterranean basin. In the western Mediterranean, the anomalous southwesterly surface to mid-tropospheric flow is connected with enhanced moisture transport from the Atlantic. During ≥5-year return level events, the subtropical jet stream axis is aligned with the African coastline and interacts with the eddy-driven jet stream. This is connected with enhanced large scale ascending motions, instability and leads to the development of severe precipitation events. For the eastern Mediterranean extreme precipitation events, the identified anomaly patterns suggest warm air advection connected with anomalous ascent motions and an increase of the low- to mid-tropospheric moisture. Furthermore, the jet stream position (during ≥5-year return level events) supports the eastern basin being in a divergence area, where ascent motions are favoured. Our results contribute to an improved understanding of daily precipitation extremes in the cold season and associated large scale atmospheric features.
Risk factors for worker injury and death from occupational light vehicles crashes in New South Wales (Australia)
Authors: Stuckey Rwth , Glass Deborah C. , LaMontagne Anthony D. , Wolfe Rory , Sim Malcolm R.
Published: May 2010

Background/Aim

To identify risk and protective factors for crash casualty outcomes in occupational light vehicles (OLV), a previously under‐recognized work context for injuries and fatalities.

Methods

A register‐based study was conducted using linked vehicle crash and registration data (n = 13,491) for the Australian state of New South Wales. Univariate and multivariate analyses were undertaken to assess the relationship between casualty outcomes and variables drawn from four domains of potential determinants of severity: user, vehicle, road, and work organization factors.

Results

Nineteen percent of OLV crashes had OLV‐user casualties (n = 2,506) and 1% fatalities (n = 34). Adjusted casualty risk factors included tired driver (OR 2.1, 95% CI 1.5–2.7), no seat belt use (OR 1.8, 95% CI 1.4–2.3), and excessive speed (OR 1.4, 95% CI 1.2–1.6). Adjusted fatality risk factors were no seat belt (OR 12.9, 95% CI 4.9–34.3) and high‐speed zone crash (OR 5.0, 95% CI 2.1–12.3).

Conclusions

OLV users are at risk from both recognized road risks and hazards specific to OLV use. Findings suggest that risk reduction could be improved by the use of safer vehicles, fatigue management, and journey planning. Am. J. Ind. Med. 53:931–939, 2010. © 2010 Wiley‐Liss, Inc.
Experimental investigation into the effect of adhesion properties of PEEK modified by atmospheric pressure plasma and low pressure plasma
Authors: Jha Sangeeta , Bhowmik Shantanu , Bhatnagar Nitu , Bhattacharya Nayan Kamal , Deka Utpal , Iqbal Hafiz Mohammad Salim , Benedictus Rinze
Published: May 2010

High performance polymer, Polyether Ether Ketone (PEEK) (service temperature −250°C to +300°C, tensile strength: 120 MPa) is gaining significant interest in aerospace and automotive industries. In this investigation, attention is given to understand adhesion properties of PEEK, when surface of the PEEK is modified by two different plasma processes (i) atmospheric pressure plasma and (ii) low pressure plasma under DC Glow Discharge. The PEEK sheets are fabricated by ultra high temperature resistant epoxy adhesive (DURALCO 4703, service temperature −260°C to +350°C). The surface of the PEEK is modified through atmospheric pressure plasma with 30 and 60 s of exposure and low pressure plasma with 30, 60, 120, 240, and 480 s of exposure. It is observed that polar component of surface energy leading to total surface energy of the polymer increases significantly when exposed to atmospheric pressure plasma. In the case of low pressure plasma, polar component of surface energy leading to total surface energy of the polymer increases with time of exposure up to 120 s and thereafter, it deteriorates with increasing time of exposure. The fractured surface of the adhesively bonded PEEK is examined under SEM. It is observed that unmodified PEEK fails essentially from the adhesive to PEEK interface resulting in low adhesive bond strength. In the case of surface modified PEEK under atmospheric pressure plasma, the failure is entirely from the PEEK and essentially tensile failure at the end of the overlap resulting in significant increase in adhesive bond strength. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Novel clay‐based nanobiocomposites of biopolyesters with synergistic barrier to UV light, gas, and vapour
Authors: Sanchez‐Garcia M. D. , Lagaron J. M.
Published: May 2010

This article presents novel solvent cast biocomposites of poly(lactic acid) (PLA), polyhydroxybutyrate‐co‐valerate (PHBV), and polycaprolactone (PCL) with enhanced barrier properties to UV light, oxygen, water, and limonene by means of incorporating an organomodified mica‐based clay grade. The TEM results suggested a good clay dispersion but with no exfoliation in the three biopolyesters. In agreement with the crystallinity data, which was found to generally increase with increasing filler content, oxygen but specially water and d‐limonene permeability coefficients were seen to decrease to a significant extent in the biocomposites and an optimum property balance was found for 5 wt % of clay loading in the three biopolymers. With increasing clay content, the light transmission of these biodegradable biocomposites decreased by up to 90% in the UV wavelength region due to the specific UV blocking nature of the clay used. As a result, these new biocomposites can have significant potential to develop packaging films, coatings and membranes with enhanced gas and vapor barrier properties and UV blocking performance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Online pressure–volume–temperature measurements of polypropylene using a testing mold to simulate the injection‐molding process
Authors: Wang Jian , Xie Pengcheng , Yang Weimin , Ding Yumei
Published: May 2010

To obtain accurate prediction of service performance and service life of polymers and to optimize the processing parameters, a modified online measurement was used to measure the pressure–volume–temperature (PVT) properties of polymers under certain processing conditions. The measurement was based on an injection molding machine, and it was used to obtain the PVT data of polymers directly with a special testing mold under normal processing conditions. The PVT properties of a semicrystalline polymer, polypropylene, were measured through both an online testing mold and a conventional piston–die dilatometer. The PVT properties were correlated by a modified two‐domain Tait equation of state. The differences between the two groups of PVT data measured were investigated, and relative differences, especially in the rubbery state because of different cooling or heating measuring modes and sample forms, were observed. Numerical simulations of injection‐molding processes were carried out by Moldflow software with both of the types of PVT data. The resulting online PVT data exhibited improvement in the accurate prediction of shrinkage and warpage. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effect of 3‐(trimethoxysilyl) propyl methacrylate on the mechanical, thermal, and morphological properties of poly(methyl methacrylate)/hydroxyapatite composites
Authors: Tham W. L. , Chow W. S. , Ishak Z. A. Mohd
Published: May 2010

The poly(methyl methacrylate)/hydroxyapatite (PMMA/5HA) composites were prepared by using heat‐processing polymers powder and liquid method with a ratio of 10 : 4 according to the dental laboratory practice. The hydroxyapatite (HA) was surface treated using 3‐(trimethoxysilyl) propyl methacrylate (γ‐MPS) with different concentrations based on HA (i.e., 2, 4, 6, and 8%). The chemical treatment of HA was examined using Fourier Transform Infrared Ray Spectroscopy (FTIR). The mechanical properties of PMMA/5HA composites were characterized using tensile, 3‐point bending flexural and fracture toughness tests. The morphological properties of the PMMA/5HA composites were characterized using field emission scanning electron microscopy (FESEM). The intensities of absorption bands at 840, 873, and 1031 cm−1 which are corresponding to SiO stretching were observed and became higher as the increasing concentration of γ‐MPS for the HA treatment. This indicates that the HA was successfully treated by γ‐MPS. It is interesting to note that the flexural modulus and strength of PMMA/5HA was increased significantly by 6% γ‐MPS. The improvement of the mechanical strength could be related to the enhancement of interfacial interaction between PMMA and HA by the surface treatment of γ‐MPS. In addition, the fracture toughness properties of PMMA/5HA composites were also influenced by the different concentration of γ‐MPS. It is believed that the γ‐MPS could act as a good silane coupling agent for the PMMA/5HA composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Polyamide 66 binary and ternary nanocomposites: Mechanical and morphological properties
Authors: Mert Miray , Yilmazer Ulku
Published: May 2010

Polyamide 66 (PA 66)/impact modifier blends and polyamide/organoclay binary and PA 66/organoclay/impact modifier ternary nanocomposites were prepared by the melt‐compounding method, and the effects of the mixing sequences on the morphology and mechanical and flow properties were investigated. Lotader AX8840 and Lotader AX8900 were used as impact modifiers. The concentrations of the impact modifiers and the organoclay (Cloisite 25A) were maintained at 2 and 5 wt %, respectively. Both the binary and ternary nanocomposites displayed high tensile strength and Young's modulus values compared to the PA 66/impact modifier blends. Decreases occurred in the strength and stiffness of the binary nanocomposites upon incorporation of the elastomeric materials into the polymeric matrix. In general, the mixing sequence in which all three ingredients were added simultaneously and extruded twice (the All‐S mixing sequence) exhibited the most enhanced mechanical properties in comparison with the mixing sequences in which two of the components were extruded in the first extrusion step and the third ingredient was added in the second extrusion step. The mechanical test results were in accordance with the organoclay dispersion. The impact strength was highly affected by the elastomeric domain sizes, interdomain distances, interfacial interactions, and organoclay delamination. The smallest elastomeric domain size was obtained for the All‐S mixing sequence, whereas the elastomeric domain sizes of the other mixing sequences were quite close to each other. Drastic variations were not observed between the melt viscosities of the ternary nanocomposites prepared with different mixing sequences. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A study on Xe excilamp treatment of wool fibers
Authors: Yang Mei , Yan Kelu , Zhou Aojia
Published: May 2010

A Xeexcilamp (λ = 172 nm) was applied to photo irradiate and surface modify wool fibers. The scanning electron microscopy (SEM) showed that the outer surface of the fibers was etched after excilamp treatment, and some microcracks emerged on the surface scales. X‐ray photoelectron spectroscopy (XPS) analysis indicated that the excilamp‐treated fibers possessed high concentration of oxygen, sulfur, and nitrogen, as well as increased hydrophilic groups, such as hydroxyl group, carboxyl group, and sulphur oxide species on the surface. Fourier transform infrared spectroscopy with attenuated total internal reflectance (FTIR‐ATR) mode measurement showed that the sulphur oxide species was mainly composed of cysteic acid and S‐sulphonate together with a small amount of cystine monoxide and cystine dioxide on the outer surface of excilamp‐treated wool fiber. The contact angle of water on the excilamp‐treated fiber decreased about 110°. Using an acid dye, deeper hue was achieved in dyeing the treated fibers, evidenced by improved relative color strength (K/S) and brightness (L*) values. And the directional friction effect (DFE) of the wool fibers in wet obviously decreased after the excilamp treatment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Copper‐ion adsorption and gold‐ion reduction by polyphenols prepared by the enzymatic reaction of horseradish peroxidase
Authors: Kawakita Hidetaka , Nakano Sachiko , Hamamoto Kohshi , Matsunaga Yumi , Yoshimura Yuko , Ohto Keisuke , Inoue Katsutoshi
Published: May 2010

Polyphenols were synthesized via a horseradish peroxidase reaction from phenol, catechol, and pyrogallol for use as copper‐ion adsorbents. The molecular weights of the polyphenols ranged from about 1000 to 3000 g/mol. The hydroxyl group contents in the polyphenols from phenol, catechol, and pyrogallol were 5.9, 4.0, and 0.94 mol/kg, respectively, as determined by titration. The saturation binding capacity for copper ions of the polyphenols from phenol, catechol, and pyrogallol were calculated to be 1.44, 0.88, and 0.22 mol/kg, respectively, at pH 4.5. Copper ions were efficiently adsorbed via an ion‐exchange interaction by the synthesized polyphenols with vicinal hydroxyl groups, and those polyphenols could be applied to metal adsorption. Gold ions were selectively reduced by the phenol group in polypyrogallol in acid media to form gold particles. The reduced gold particles were eluted with a solution of 1.0M thiourea plus 0.5M HCl. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Interaction between the fluorinated amphiphilic copolymer poly(2,2,3,4,4,4‐hexafluorobutyl methacrylate)‐graft‐poly(SPEG) and DNA
Authors: Li Ling , Xiong Shengdong , Wang Yingxi , Song Gongwu , Wu Shuilin , Chu Paul K. , Xu Zushun
Published: May 2010

A synthesized copolymer, synthesized from HFMA (hexaflurobutyl methacrylate) and SPEG (PHFMA‐g‐PSPEG), was synthesized. PHFMA‐g‐PSPEG intercalated to the DNA base pair via a strong hydrophobic force, and this was conformed by ultraviolet spectroscopy, transmittance measurements, micropolarity measurements, resonance light scattering (RLS) spectroscopy, and particle size measurements. The copolymer was used as a new probe to detect DNA according to the RLS technique. The hydrophobic interaction between PHFMA‐g‐PSPEG and DNA significantly enhanced the RLS signal, and the enhanced RLS intensity at 422 nm was proportional to the nucleic acid concentration within the range of 0.09–0.90 mg/L with a detection limit (3σ) of 4.0 μg/L. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of the electrospun nanofibers loaded with clarithromycin
Authors: Wei Anfang , Wang Juan , Wang Xueqian , Wei Qufu , Ge Mingqiao , Hou Dayin
Published: May 2010

Electrospinning was applied to prepare the drug‐loaded nanofibers for potential use in drug delivery and wound healing. Clarithromycin (CLM) was selected as the model drug, whereas poly(l‐lactic acid) (PLLA) was used as the biodegradable and biocompatible polymer carrier. The low toxicity solvents were tested, and the morphology and structures of the nanofibers were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and X‐ray diffraction (XRD). PLLA and its composite of CLM were electrospun using the solvents of dichloromethane and acetone. SEM images showed that the diameters of the electrospun PLLA fibers were about 1000 nm, decreased to about 400 nm when 5 wt % CLM was loaded. With the increase of the amount the drug loaded, the diameters of the fibers gradually decreased and their distributions varied. The drug aggregates of any kind were not observed on the surfaces of the fibers. FTIR spectra revealed that CLM was incorporated into the macromolecular carrier of PLLA by formation of the hydrogen bonds but no new functional groups in the structure of the composite nanofibers were formed. XRD patterns indicated that the drug distributed in the composite nanofibers existed in the noncrystalline form. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Melt density and volume flow rate of polypropylene/Al(OH)3/Mg(OH)2 flame retardant composites
Authors: Liang J. Z. , Tang C. Y. , Zhang Y. J.
Published: May 2010

Polypropylene (PP) flame retardant composites filled with aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2) as well as zinc borate (ZB) were prepared with a twin‐screw extruder. The melt volume flow rate (MVR) and density of the composites were measured by means of a melt flow rate instrument under experimental conditions with temperature of 180°C and load varying from 2.16 to 5 kg, to identify the effects of the particle size and content. The results showed that MVR of the composites decreased with an increase of the filler weigh fraction (ϕf) when ϕf was more than 10 phr. The MVR decreased first and then increased with an increase of the filler diameter (d). The melt density (ρm) of the composites increased linearly with an increase of ϕf and decreased linearly with the increase of d. In addition, the ρm increased with an increase of load. Under the same experimental conditions, the MVR decreased slightly while the ρm increased somewhat with addition of ZB for the PP/Al(OH)3/Mg(OH)2 composite systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on the structure‐mechanical properties relationship and antistatic characteristics of SSBR composites filled with SiO2/CB
Authors: Wang Lei , Zhao Suhe
Published: May 2010

The composites of solution polymerized styrene‐butadiene rubber (SSBR) filled with SiO2/carbon black (CB) were prepared by reaction blending. The mechanical and antistatic properties were studied. The morphology and dispersion of the two kinds of nano‐fillers in the composites were observed. The results showed that CB presented 30 nm spherical particles and formed filler networks in the SSBR/CB composite. Payne effect of the SSBR/CB composite was large and the antistatic property was excellent; SiO2 powder presented 20–40 nm irregular particles and also formed filler networks in the SSBR/SiO2 composite. The internal friction of the SSBR/SiO2 composite was low, however, the static accumulation was obviously large; SSBR/SiO2/CB composites exhibited good filler dispersion, high mechanical properties and low internal friction. The rolling resistance, wet‐skid resistance and wear resistance are well balanced. Among these, the composite filled with SiO2/CB in 20/50 achieved the best overall performances. The surface and volume resistivity of the composites was increased with increasing amount of SiO2. For the researched formulation, the ratio of SiO2/CB in 35/35 was the percolation threshold for the antistatic property of the composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Enhanced photodegradation efficiency of polyethylene‐TiO2 nanocomposite film with oxidized polyethylene wax
Authors: Fa Wenjun , Yang Changjun , Gong Chuqing , Peng Tianyou , Zan Ling
Published: May 2010

A novel photodegradable polyethylene‐oxidized polyethylene wax‐TiO2 (PE‐OPW‐TiO2) nanocomposite film was prepared by embedding the organically modified TiO2 nanoparticles into commercial PE in the presence of OPW. The photocatalytic degradation behavior under ultraviolet light or solar light was investigated by examining the weight loss of the composite films, UV–vis transmittance spectrum, scanning electron microscope (SEM), and gel permeation chromatogram (GPC). The results show that OPW, as a dispersant and a compatibiliser, markedly improves the dispersion and compatibility of TiO2 nanoparticles in PE resins. The PE‐OPW‐TiO2 composite film demonstrates much higher photodegradation efficiency and much better mechanical property than either the PE‐TiO2 composite film or the pure PE film. The weight‐average molecular weight (Mw) of the PE‐OPW‐TiO2 composite film decreased 94.3% and the number‐average molecular weight (Mn) decreased 84.5% after 38 days solar light irradiation. The photocatalytic degradation mechanism of the film is briefly discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Postnatal Development of the Lamina Reticularis in Primate Airways
Authors: Evans Michael J. , Fanucchi Michelle V. , Plopper Charles G. , Hyde Dallas M.
Published: May 2010

The basement membrane zone (BMZ) appears as three component layers: the lamina lucida, lamina densa, and lamina reticularis. The laminas lucida and densa are present during all stages of development. The lamina reticularis appears during postnatal development. Collagens I, III, and V form heterogeneous fibers that account for the thickness of the lamina reticularis. Additionally, there are three proteoglycans considered as integral components of the BMZ: perlecan, collagen XVIII, and bamacan. Perlecan is the predominant heparan sulfate proteoglycan in the airway BMZ. It is responsible for many of the functions attributed to the BMZ, in particular, trafficking of growth factors and cytokines between epithelial and mesenchymal cells. Growth factor binding sites on perlecan include FGF‐1, FGF‐2, FGF‐7, FGF‐10, PDGF, HGF, HB‐EGF, VEGF, and TGF‐β. Growth factors pass through the BMZ when moving between the epithelial and mesenchymal cell layers. They move by rapid reversible binding with sites on both the heparan sulfate chains and core protein of perlecan. In this manner, perlecan regulates movement of growth factors between tissues. Another function of the BMZ is storage and regulation of FGF‐2. FGF‐2 has been shown to be involved with normal growth and thickening of the BMZ. Thickening of the BMZ is a feature of airway remodeling in asthma. It may have a positive effect by protecting against airway narrowing and air trapping. Conversely, it may have a negative effect by influencing trafficking of growth factors in the epithelial mesenchymal trophic unit. However, currently the significance of BMZ thickening is not known. Anat Rec, 293:947–954, 2008. © 2008 Wiley‐Liss, Inc.
Heparan Sulfates in the Lung: Structure, Diversity, and Role in Pulmonary Emphysema
Authors: Smits Nicole C. , Shworak Nicholas W. , Dekhuijzen P.N. Richard , van Kuppevelt Toin H.
Published: May 2010

There is an emerging interest in the extracellular matrix (ECM) of the lung, especially in the role it plays in development and disease. There is a rapid change from the classical view of the ECM as a supporting structure towards a view of the ECM as a regulatory entity with profound effects on proliferation, migration, and differentiation of pulmonary cells. In the ECM, a variety of molecules is present in a highly organized pattern. Next to the abundant fiber‐forming molecules such as collagens and elastin, a large number of less abundant molecules are part of the ECM, including proteoglycans. In this review, we will focus on one class of proteoglycans, the heparan sulfate proteoglycans. We will particularly address the structure, biosynthesis, and function of their saccharide moiety, the heparan sulfates, including their role in development and (patho)physiology. Anat Rec, 293:955–967, 2010. © 2010 Wiley‐Liss, Inc.
RFLP analysis and allelic discrimination with real‐time PCR using the human lactase persistence trait
Authors: Weinlander Kenneth M. , Hall David J. , De Stasio Elizabeth A.
Published: May 2010

We describe here two open‐ended laboratory investigations for an undergraduate laboratory course that uses students' DNA as templates for quantitative real‐time PCR and for traditional PCR followed by RFLP analysis. Students are captivated by the immediacy of the application and the relevance of the genotypes and traits, lactase persistence or nonpersistence, under study. Concepts ranging from nucleotide polymorphisms to natural selection can be demonstrated and reinforced by these laboratories. Students have a high degree of success with the laboratories and both objective and self‐assessments of student learning indicate that concepts and techniques are better understood following implementation of these laboratory investigations.
A research‐based laboratory course designed to strengthen the research‐teaching nexus
Authors: Parra Karlett J. , Osgood Marcy P. , Pappas Donald L.
Published: May 2010

We describe a 10‐week laboratory course of guided research experiments thematically linked by topic, which had an ultimate goal of strengthening the undergraduate research‐teaching nexus. This undergraduate laboratory course is a direct extension of faculty research interests. From DNA isolation, characterization, and mutagenesis, to protein expression and structural analysis, the research protocols were adapted to suit the weekly 3‐hour biochemistry course. The experiments described are flexible and hypothesis driven, allowing original research to be conducted. Students gain practice in some of the most common techniques used in biochemistry and molecular biology, including minipreps and DNA spectrophometric analysis, DNA restriction digestion and agarose gel electrophoresis, PCR mutagenesis, DNA sequencing analyses, E. coli transformations, whole cell protein extractions, SDS‐PAGE, immunoblots, molecular modeling, and bioinformatics. The studies that begun in the classroom were continued in the research laboratory by undergraduate students, and eventually, the results were published in peer reviewed research articles. This research‐educational program effectively integrated basic research endeavors into the undergraduate curriculum. It proved to be synergistic by nature: research stimulated teaching and teaching supported research. In our experience, this is an effective mechanism to conduct productive research while satisfying teaching duties in undergraduate institutions, where scholarly research is expected but teaching is the primary mission.
Assessing how science faculty learning communities promote scientific teaching
Authors: Sirum Karen L. , Madigan Dan
Published: May 2010

Although there is a need for continued pedagogical advancement in science undergraduate education, what is needed more urgently is more widespread adaptation of pedagogical practices that research has already shown to promote learning. Those practices include interactive engagement pedagogies such as active learning and inquiry‐based learning. The need now is to find ways to integrate and institutionalize these evidence‐based strategies for teaching science and to help science faculty learn about and implement them. Scientific Teaching Learning Communities (STLCs) create a culture that values scholarly teaching within science departments, important for bridging the gap between science and education and for improving undergraduate science learning. Evidence for the impact of STLCs on the student‐learning environment was obtained through the development and use of the Participant Assessment of Learning Gains survey, an adaptation of the online Student Assessment of Learning Gains survey originally developed by Seymour et al. (Available at: http://www.wcer.wisc.edu/salgains/instructor/SALGains.asp, 1997 and Paper presented at the National Meeting of the American Chemical Society, 2000). Data reveal how STLCs are transforming faculty behavior and directly affecting what they do in their science classrooms.
Designing laboratory exercises for the undergraduate molecular biology/biochemistry student: Techniques and ethical implications involved in personalized medicine
Authors: Weinlander Kenneth M. , Hall David J.
Published: May 2010

Personalized medicine refers to medical care that involves genetically screening patients for their likelihood to develop various disorders. Commercial genome screening only involves identifying a consumer's genotype for a few single nucleotide polymorphisms. A phenotype (such as an illness) is greatly influenced by three factors: genes, gene expression levels, and the environment. The information supplied by personal genomics companies only involves genes and as such is not always indicative of a particular phenotype. Here, we propose a method for developing modular undergraduate laboratories that examine each contributing factor for a single gene. Although each module is suitable as an individual laboratory exercise, every module may be used in the same class to examine a single phenotype of interest, give students a more complete understanding of how a phenotype is produced and allow students to understand the science behind personalized medicine.
Problem‐based test: Functional analysis of mutant 16S rRNAs
Authors: Szeberényi József
Published: May 2010

Terms to be familiar with before you start to solve the test: ribosome, ribosomal subunits, antibiotics, point mutation, 16S, 5S, and 23S rRNA, Shine‐Dalgarno sequence, mRNA, tRNA, palindrome, hairpin, restriction endonuclease, fMet‐tRNA, peptidyl transferase, initiation, elongation, termination of translation, expression plasmid, transformation, β‐galactosidase, and ribosome translocation.