bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoprene in poplar emissions: effects on new particle formation and OH concentrations
Authors: Kiendler-Scharr A. , Andres S. , Bachner M. , Behnke K. , Broch S. , Hofzumahaus A. , Holland F. , Kleist E. , Mentel T. F. , Rubach F. , Springer M. , Steitz B. , Tillmann R. , Wahner A. , Schnitzler J.-P. , Wildt J.
Published: January 2012

Abstract. Stress-induced volatile organic compound (VOC) emissions from transgenic Grey poplar modified in isoprene emission potential were used for the investigation of photochemical secondary organic aerosol (SOA) formation. In poplar, acute ozone stress induces the emission of a wide array of VOCs dominated by sesquiterpenes and aromatic VOCs. Constitutive light-dependent emission of isoprene ranged between 66 nmol m−2 s−1 in non-transgenic controls (wild type WT) and nearly zero (<0.5 nmol m−2 s−1) in isoprene emission-repressed plants (line RA22), respectively. Nucleation rates of up to 3600 cm−3 s−1 were observed in our experiments. In the presence of isoprene new particle formation was suppressed compared to non-isoprene containing VOC mixtures. Compared to isoprene/monoterpene systems emitted from other plants the suppression of nucleation by isoprene was less effective for the VOC mixture emitted from stressed poplar. This is explained by the observed high efficiency of new particle formation for emissions from stressed poplar. Direct measurements of OH in the reaction chamber revealed that the steady state concentration of OH is lower in the presence of isoprene than in the absence of isoprene, supporting the hypothesis that isoprenes' suppressing effect on nucleation is related to radical chemistry. In order to test whether isoprene contributes to SOA mass formation, fully deuterated isoprene (C5D8) was added to the stress-induced emission profile of an isoprene free poplar mutant. Mass spectral analysis showed that, despite the isoprene-induced suppression of particle formation, fractions of deuterated isoprene were incorporated into the SOA. A fractional mass yield of 2.3% of isoprene was observed. Future emission changes due to land use and climate change may therefore affect both gas phase oxidation capacity and new particle number formation.
Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igeneous Complex, South Africa
Authors: Hirsikko A. , Vakkari V. , Tiitta P. , Manninen H. E. , Gagné S. , Laakso H. , Kulmala M. , Mirme A. , Mirme S. , Mabaso D. , Beukes J. P. , Laakso L.
Published: January 2012

Abstract. South Africa holds significant mineral resources, with a substantial fraction of these reserves occurring in a large geological structure termed the Bushveld Igeneous Complex (BIC). The majority of the world's platinum group metals (PGMs) and chromium originate from the BIC. Considering the importance of PGMs in the manufacturing of automotive catalytic converters, as well as the relatively poor current state of air quality and the general lack of atmospheric research in the BIC, atmospheric related research in this geographical area is of local (South African) and of international interest. The western limb of the BIC is the most exploited, with at least eleven pyrometallurgical smelters occurring within a 55 km radius. Due to the lure of employment in the industrialised BIC, the area is populated by informal, semi-formal and formal residential developments. In order to investigate the characteristics and processes affecting sub-micron particle number concentrations and formation events, air ion and aerosol particle size distribution and concentration measurements were conducted for over two years at Marikana in the heart of the western BIC. Our results indicated that high amounts of Aitken and accumulation mode particles originated from domestic burning for heating and cooking in the morning and evening, while during daytime SO2-based nucleation (from industrial emissions) was the most probable source for large number concentrations of nucleation and Aitken mode particles. Nucleation event day frequency was extremely high, i.e. 86% of the analysed days, which to the knowledge of the authors is the highest frequency ever reported. Secondary particle formation was influenced both by local pollution sources and regional ambient conditions. Therefore, our observation of the annual cycle and magnitude of the particle formation and growth rates during nucleation events were similar to the results from a semi-clean savannah site in South Africa.
A Tropospheric ozone maximum over the equatorial southern Indian Ocean
Authors: Zhang L. , Li Q. B. , Murray L. T. , Luo M. , Liu H. , Jiang J. H. , Mao Y. , Chen D. , Gao M. , Livesey N.
Published: January 2012

Abstract. We examine the distribution of tropical tropospheric ozone (O3) from the Microwave Limb Sounder (MLS) and the Tropospheric Emission Spectrometer (TES) by using a global three-dimensional model of tropospheric chemistry (GEOS-Chem). MLS and TES observations of tropospheric O3 during 2005 to 2009 reveal a distinct, persistent O3 maximum, both in mixing ratio and tropospheric column, in May over the Equatorial Southern Indian Ocean (ESIO). The maximum is most pronounced in 2006 and 2008 and less evident in the other three years. This feature is also consistent with the total column O3 observations from the Ozone Mapping Instrument (OMI) and the Atmospheric Infrared Sounder (AIRS). Model results reproduce the observed May O3 maximum and the associated interannual variability. The origin of the maximum reflects a complex interplay of chemical and dynamic factors. The O3 maximum is dominated by the O3 production driven by lightning nitrogen oxides (NOx) emissions, which accounts for 62% of the tropospheric column O3 in May 2006. We find the contribution from biomass burning, soil, anthropogenic and biogenic sources to the O3 maximum are rather small. The O3 productions in the lightning outflow from Central Africa and South America both peak in May and are directly responsible for the O3 maximum over the western ESIO. The lightning outflow from Equatorial Asia dominates over the eastern ESIO. The interannual variability of the O3 maximum is driven largely by the anomalous anti-cyclones over the southern Indian Ocean in May of 2006 and 2008. The lightning outflow from Central Africa and South America is effectively entrained by the anti-cyclones followed by northward transport to the ESIO.
Can a global model reproduce observed trends in summertime surface ozone levels?
Authors: Koumoutsaris S. , Bey I.
Published: January 2012

Abstract. Quantifying trends in surface ozone concentrations are critical for assessing pollution control strategies. Here we use observations and results from a global chemical transport model to examine the trends (1991–2005) in daily maximum 8-hour average concentrations in summertime surface ozone at rural sites in Europe and the United States. We find a decrease in observed ozone concentrations at the high end of the probability distribution at many of the sites in both regions. The model attributes these trends to a decrease in local anthropogenic ozone precursors, although simulated decreasing trends are overestimated in comparison with observed ones. The low end of observed distribution show small upward trends over Europe and the western US and downward trends in Eastern US. The model cannot reproduce these observed trends, especially over Europe and the western US. In particular, simulated changes between the low and high end of the distributions in these two regions are not significant. Sensitivity simulations indicate that emissions from far away source regions do not affect significantly ozone trends at both ends of the distribution. This is in contrast with previously available results, which indicated that increasing ozone trends at the low percentiles may reflect an increase in ozone background associated with increasing remote sources of ozone precursors. Possible reasons for discrepancies between observed and simulated trends are discussed.
Enhanced solar energy absorption by internally-mixed black carbon in snow grains
Authors: Flanner M. G. , Liu X. , Zhou C. , Penner J. E.
Published: January 2012

Abstract. Here we explore light absorption by snowpack containing black carbon (BC) particles residing within ice grains. Basic considerations of particle volumes and BC/snow mass concentrations show that there are generally 0.05–109 BC particles for each ice grain. This suggests that internal BC is likely distributed as multiple inclusions within ice grains, and thus the dynamic effective medium approximation (DEMA) (Chýlek and Srivastava, 1983) is a more appropriate optical representation for BC/ice composites than coated-sphere or standard mixing approximations. DEMA calculations show that the 460 nm absorption cross-section of BC/ice composites, normalized to the mass of BC, is typically enhanced by factors of 1.8–2.1 relative to interstitial BC. BC effective radius is the dominant cause of variation in this enhancement, compared with ice grain size and BC volume fraction. We apply two atmospheric aerosol models that simulate interstitial and within-hydrometeor BC lifecycles. Although only ~2% of the atmospheric BC burden is cloud-borne, 71–83% of the BC deposited to global snow and sea-ice surfaces occurs within hydrometeors. Key processes responsible for within-snow BC deposition are development of hydrophilic coatings on BC, activation of liquid droplets, and subsequent snow formation through riming or ice nucleation by other species and aggregation/accretion of ice particles. Applying deposition fields from these aerosol models in offline snow and sea-ice simulations, we calculate that 32–73% of BC in global surface snow resides within ice grains. This fraction is smaller than the within-hydrometeor deposition fraction because meltwater flux preferentially removes internal BC, while sublimation and freezing within snowpack expose internal BC. Incorporating the DEMA into a global climate model, we simulate increases in BC/snow radiative forcing of 43–86%, relative to scenarios that apply external optical properties to all BC. We show that snow metamorphism driven by diffusive vapor transfer likely proceeds too slowly to alter the mass of internal BC while it is radiatively active, but neglected processes like wind pumping and convection may play much larger roles. These results suggest that a large portion of BC in surface snowpack may reside within ice grains and increase BC/snow radiative forcing, although measurements to evaluate this are lacking. Finally, previous studies of BC/snow forcing that neglected this absorption enhancement are not necessarily biased low, because of application of absorption-enhancing sulfate coatings to hydrophilic BC, neglect of coincident absorption by dust in snow, and implicit treatment of cloud-borne BC resulting in longer-range transport.
Changes in the Adriatic oceanographic properties induced by the Eastern Mediterranean Transient
Authors: Vilibić I. , Matijević S. , Šepić J.
Published: January 2012

Abstract. Long-term time series of physical and chemical parameters collected between 1960 and 2010 along the Palagruža Sill transect, middle Adriatic Sea, have been investigated in terms of average water properties and their variability. Nutrients, especially orthophosphates, reached rather higher levels of concentration below the euphotic zone between 1991 and 1998, the highest in the investigated period. Simultaneously, the N:P ratio, which is normally larger than 25:1, decreased to values less than 16:1 in the euphotic zone, indicating a switch from typical phosphorus-limited to nitrogen-limited preconditioning of the primary production. Higher-than-usual nutrient levels, coupled with lower-than-usual temperature, salinity and dissolved oxygen, have been attributed to the intermediate inflow of the nutrient richer Western Mediterranean waters to the Adriatic, entering the Adriatic during the anticyclonic phase of the Bimodal Adriatic-Ionian Oscillation (BiOS). The BiOS and the Northern Ionian anticyclone have been uniquely strengthened by the Eastern Mediterranean Transient occurring in the early 1990s. The observed changes have a potential to impact the primary production and presumably the whole trophic chain in the Adriatic and were likely responsible for the observed fluctuation in abundances of various species and fish stock, indicating a high relevance of the observed physical processes.
The blue water footprint of electricity from hydropower
Authors: Mekonnen M. M. , Hoekstra A. Y.
Published: January 2012

Abstract. Hydropower accounts for about 16% of the world's electricity supply. It has been debated whether hydroelectric generation is merely an in-stream water user or whether it also consumes water. In this paper we provide scientific support for the argument that hydroelectric generation is in most cases a significant water consumer. The study assesses the blue water footprint of hydroelectricity – the water evaporated from manmade reservoirs to produce electric energy – for 35 selected sites. The aggregated blue water footprint of the selected hydropower plants is 90 Gm3 yr−1, which is equivalent to 10% of the blue water footprint of global crop production in the year 2000. The total blue water footprint of hydroelectric generation in the world must be considerably larger if one considers the fact that this study covers only 8% of the global installed hydroelectric capacity. Hydroelectric generation is thus a significant water consumer. The average water footprint of the selected hydropower plants is 68 m3 GJ−1. Great differences in water footprint among hydropower plants exist, due to differences in climate in the places where the plants are situated, but more importantly as a result of large differences in the area flooded per unit of installed hydroelectric capacity. We recommend that water footprint assessment is added as a component in evaluations of newly proposed hydropower plants as well as in the evaluation of existing hydroelectric dams, so that the consequences of the water footprint of hydroelectric generation on downstream environmental flows and other water users can be evaluated.
Reverse flood routing with the inverted Muskingum storage routing scheme
Authors: Koussis A. D. , Mazi K. , Lykoudis S. , Argiriou A. A.
Published: January 2012

Abstract. This work treats reverse flood routing aiming at signal identification: inflows are inferred from observed outflows by orienting the Muskingum scheme against the wave propagation direction. Routing against the wave propagation is an ill-posed, inverse problem (small errors amplify, leading to large spurious responses); therefore, the reverse solution must be smoothness-constrained towards stability and uniqueness (regularised). Theoretical constrains on the coefficients of the reverse routing scheme assist in error control, but optimal grids are derived by numerical experimentation. Exact solutions of the convection-diffusion equation, for a single and a composite wave, are reverse-routed and in both instances the wave is backtracked well for a range of grid parameters. In the arduous test of a square pulse, the result is comparable to those of more complex methods. Seeding outflow data with random errors enhances instability; to cope with the spurious oscillations, the reversed solution is conditioned by smoothing via low-pass filtering or optimisation. Good-quality inflow hydrographs are recovered with either smoothing treatment, yet the computationally demanding optimisation is superior. Finally, the reverse Muskingum routing method is compared to a reverse-solution method of the St. Venant equations of flood wave motion and is found to perform equally well, at a fraction of the computing effort. This study leads us to conclude that the efficiently attained good inflow identification rests on the simplicity of the Muskingum reverse routing scheme that endows it with numerical robustness.
Serial MRI and CSF Analysis in a Dog Treated with Intrathecal Amphotericin B for Protothecosis
Authors: Young Martin , Bush William , Sanchez Melissa , Gavin Pat , Williams Mathew
Published: January 2012

A 3 yr old female spayed English setter mixed-breed dog presented with diarrhea, weight loss, side stepping to the right, and a right head tilt. Rectal and cerebrospinal fluid cytology and culture confirmed a diagnosis of Prototheca zopfii. MRI of the brain showed inflammation of the brain and meninges, ventriculomegaly, and syringomyelia. Treatment with prednisone, itraconazole, and amphotericin B lipid complex administered intrathecally yielded transient improvement. Progressive brainstem signs were noted, and a repeat MRI and cerebrospinal fluid analysis documented persistent disease. This is the first description of the MRI findings and treatment with intrathecal amphoteracin B lipid complex for protothecosis of the central nervous system. Protothecosis should be considered in dogs with chronic diarrhea and compatible MRI findings.
Unconventional Multi‐Scale Patterning of Titanium Dioxide: A New Tool for the Investigation of Cell–Topography Interactions
Authors: Biscarini Fabio , Bianchi Michele , Chelli Beatrice , Valle Francesco , Dionigi Chiara , Bystrenova Eva , Greco Pierpaolo
Published: January 2012

Titanium dioxide (TiO2) is a biocompatible material with important applications in the field of regenerative medicine. Here we show that a multi‐scale hierarchical architecture of TiO2, realized with sub‐micrometer polystyrene beads as templating agent patterned by “micromolding in capillaries” (MIMICs), is a viable functional tool for the systematic investigation of cell behavior with respect to a complex topographic texture of the substrate. TiO2 stripes of different width and interconnected porosity whose size ranges from a few hundred to a few tens nanometer, are obtained after thermal treatment of the precursors with concurrent removal of the templating agent. The adhesion and proliferation of two human secondary neural cell lines, i.e., 1321N1 astrocytoma and SH‐SY5Y neuroblastoma, on the patterns is statistically assessed with respect to the TiO2 stripe width and porosity. Our results show that cells have a strong preference for TiO2 patterns with respect to glass, the proliferation rate is not affected by cell porosity whereas adhesion is although ligthly, whereas the response of cell density to stripe width is very different in astocytoma cells with respect to neuroblastoma cells.
Palladium‐Catalyzed Direct and Site‐Selective Desulfitative Arylation of Indoles with Sodium Sulfinates
Authors: Wu Mingyue , Luo Jiaying , Xiao Fuhong , Zhang Shufeng , Deng Guo‐Jun , Luo He‐An
Published: January 2012

An efficient method was developed for the desulfitative arylation of indoles with sodium sulfinates using palladium as catalyst and copper chloride dihydrate as oxidant. The direct arylation occurred exclusively in the C‐2 position of indoles and proceeded well for a range of different substrates.
Occupational injury and work organization among immigrant Latino residential construction workers
Authors: Grzywacz Joseph G. , Quandt Sara A. , Marín Antonio , Summers Phillip , Lang Wei , Mills Thomas , Evia Carlos , Rushing Julia , Donadio Katherine , Arcury Thomas A.
Published: January 2012

Background

Rates of occupational injury among immigrant workers are widely believed to be underestimated. The goal of this study was to enhance understanding of the burden of occupational injury and the work organization factors underlying injury among immigrant Latino residential construction workers.

Methods

Prospective data were obtained from a community‐based sample of Latino residential construction workers (N = 107) over a 3‐month period.

Results

Twenty‐eight participants were injured, resulting in an injury incidence rate of 55.0/100 FTE (95% CI = 41.4–71.6) during the 3‐month observation period. The injury rate involving days away from work during the observation period was 3.9/100 FTE (CI = 0.2–7.2). Injuries were elevated among roofers relative to framers and general construction workers. Roofers had elevated exposure to a variety of deleterious work organization factors.

Conclusions

Although imprecise given the small sample, our results suggest a threefold to fourfold underestimate of the injury burden to immigrant Latino construction workers. Work organization may contribute to elevated rates of non‐fatal occupational injury, particularly among roofers. Am. J. Ind. Med. 55:698–706, 2012. © 2012 Wiley Periodicals, Inc.
The effect of mixing process on linear viscoelastic and electrical properties of ABS/MWNT nanocomposites
Authors: Mousavi Leila , Nazockdast Hossein , Mohammadi Yousef , Azizi Hamed , Saleh Zahra
Published: January 2012

The aim of this article was to study the microstructure development and the linear melt viscoelastic properties of ABS/MWNT nanocomposites. The nanocomposite samples varying in nanotube concentration (1, 2, 4, and 8 wt %) were prepared using two different methods; solution method and direct melt compounding. Results of the melt linear viscoelastic measurements performed on the nanocomposite samples prepared by both methods showed a pronounced low frequency nonterminal behavior in storage modulus along with the viscosity upturn with greater extent for the samples prepared by the solution method. The values of low frequency storage modulus for the solution processed samples were found to be increased with increasing the nanotube content up to 3 wt % above which it is increased more significantly. These results could be related to a 3D microstructure development, the extent of which was found to be enhanced in the samples prepared by the solution method due to the improving interfacial interaction and promoting the nanotube dispersion in ABS matrix. This was supported by the SEM results of the samples. Dynamic mechanical thermal analysis results of the melt‐mixed and solution‐processed samples showed that Tg of the SAN is increased about 20°C at the presence of nanotube. The results are related to the chain mobility restrictions caused by physical interaction between carbon nanotubes (CNT) and polymer chains. The electrical conductivity versus CNT content for the nanocomposite samples prepared by solution method showed a percolation behavior with CNT concentration above 4 wt % which attributed to the 3D network between nanotubes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
CO2 bubble nucleation in polystyrene: Experimental and modeling studies
Authors: Guo Zhihua , Burley Adam C. , Koelling Kurt W. , Kusaka Isamu , Lee L. James , Tomasko David L.
Published: January 2012

Polymer foams are used extensively in a variety of applications. A firm understanding of bubble nucleation is vital to predict foam properties based on process conditions. However, a number of theoretical and experimental challenges have thus far limited progress in this area. We propose the use of a scaling theory to connect nucleation behavior to well understood bulk phase behavior of polystyrene‐CO2 systems, which can be predicted by equations of state, such as the Sanchez–Lacombe equation of state. Scaling theory of nucleation asserts that when the reversible work of critical nucleus formation is properly normalized and plotted against the normalized degree of supersaturation, the resulting scaling curve is insensitive to temperature and the materials being used. Once the form of the scaling function is known, it can be used to predict the nucleation barrier knowing only the initial foaming conditions and calculating only bulk thermodynamic values. Using an extension of diffuse interface theory, we determined the slope of the scaling curve near saturation. This initial slope allows us to constrain the scaling function for better predictions of the reversible work. We also performed a series of experiments to help verify the accuracy of the scaling theory. The scaled free energy barriers determined from our experiments are consistent with the scaling function so constructed, and our theoretical results qualitatively agree with those found previously. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
2‐Amino‐3‐cyano‐4‐(5‐arylisoxazol‐3‐yl)‐4H‐chromenes: Synthesis and In Vitro Cytotoxic Activity
Authors: Akbarzadeh Tahmineh , Rafinejad Ali , Mollaghasem Javad Malekian , Safavi Maliheh , Fallah‐Tafti Asal , Pordeli Mahboobeh , Ardestani Sussan Kabudanian , Shafiee Abbas , Foroumadi Alireza
Published: January 2012

A new series of 4‐aryl‐4H‐chromenes bearing a 5‐arylisoxazol‐3‐yl moiety at the C‐4 position were prepared as potential anticancer agents. The in vitro cytotoxic activity of the synthesized compounds was investigated against a panel of tumor cell lines including MCF‐7 (breast cancer), KB (nasopharyngeal epidermoid carcinoma), Hep‐G2 (liver carcinoma), MDA‐MB‐231 (breast cancer), and SKNMC (human neuroblastoma) using the MTT colorimetric assay. Doxorubicin, a well‐known anticancer drug, was used as positive standard drug. Among the synthesized compounds, the 5‐(3‐methylphenyl)isoxazol‐3‐yl analog (7j) showed the most potent cytotoxic activity against all five human tumor cell lines.
Synthesis and Characterization of Boranate Ionic Liquids (BILs)
Authors: Bürchner Mara , Erle Anna M. T. , Scherer Harald , Krossing Ingo
Published: January 2012

Straightforward access to hydridoborate‐based ionic liquids (BILs) is provided. They fall into a barely developed area of research and are of interest as, for example, reagents for organic synthesis. A series of pure [BH4]− ILs with 1‐butyl‐2,3‐dimethylimidazolium (BMMIM), 1‐ethyl‐3‐methylimidazolium (EMMIM), 1‐propyl‐1‐methylpiperidinium (PropMPip), and1‐butyl‐1‐methylpyrrolidinium (BMP) cations were prepared. All synthesized ILs are well soluble in CH2Cl2. We developed a procedure that gives clean products with correct elemental analyses. In contrast to earlier reports, which when conducted by us yielded only mixtures of the boranate anion with major halide contamination (maximum [BH4]− content: 77.5 %). These materials can be viewed as the starting material for the (hypothetical) hydrogen‐storage redox shuttling sequence between [BH4]− and [B12H12]2−, in which the triboranate anion [B3H8]− is a formal intermediate. Here we also developed a facile route to [B3H8]− ILs with [BMMIM]+, [EMMIM]+, [PropMPip]+, and [NBu4]+, in which Na[BH4] reacts in situ (enhanced by ultrasound) with the solvent CH2Cl2 as the oxidizing agent to give the triboranate IL in high yield and purity according to the equation: 3 [BH4]−+2 CH2Cl2+[Cat]+→[B3H8]−[Cat]++H2+2 CH3Cl+2 Cl−. We further investigated this reaction path by additional NMR spectroscopic experiments, powder‐XRD analysis, and quantum chemical DFT calculations.
Supramolecular Dendrimers: Convenient Synthesis by Programmed Self‐Assembly and Tunable Thermoresponsivity
Authors: Ghosh Partha S. , Hamilton Andrew D.
Published: January 2012

We report here the noncovalent synthesis of thermosensitive dendrimers. Short oligoguanosine strands were linked to the focal point of a dendron by using “click chemistry”, and quadruplex formation was used to drive the self‐assembly process in the presence of metal ions. The dynamic nature of these noncovalent assemblies can be exploited to create combinatorial libraries of dendrimers as demonstrated by the co‐assembly of two components. These supramolecular dendrimers showed thermoresponsive behavior that can be tuned by varying the templating cations or the number of guanines in the oligonucleotide strand.
Subspecialty Training in Preventive Cardiology: The Current Status and Discoverable Fellowship Programs
Authors: Pack Quinn R. , Keteyian Steven J. , McBride Patrick E.
Published: January 2012

Background:

Preventive cardiology is currently not an American Board of Medical Specialties‐recognized subspecialty. However, several programs offer nonaccredited fellowships throughout the country. No source currently exists listing all available programs, and finding programs requires time‐intensive search strategies. Our aim was to find all current preventive cardiology fellowships in the United States and describe their basic structure, duties, and faculty.

Methods:

We searched the Internet, contacted national organizations, and networked through any institution thought likely to have a fellowship.

Results:

We found 15 programs currently offering subspecialty training in preventive cardiology but with considerably different styles, structures, duties, clinical time, lengths, and hosting departments.

Conclusions:

We provided a list of these programs and discussed the implications for the future of formal subspecialty preventive cardiology education. © 2012 Wiley Periodicals, Inc.

Dr. McBride is codirector of one of the fellowship programs listed, but otherwise has no relevant disclosures. The authors have no funding, financial relationships, or conflicts of interest to disclose.
Assessment of surface water resources and evapotranspiration in the Haihe River basin of China using SWAT model
Authors: Sun Chen , Ren Li
Published: January 2012

Quantitative assessment of surface water resources (SWRs) and evapotranspiration (ET) is essential and significant for reasonably planning and managing water resources in the Haihe River basin which is facing severe water shortage. In this study, a distributed hydrological model of the Haihe River basin was constructed using the Soil and Water Assessment Tool, well considering the reservoirs and agricultural management practices for reasonable simulation. The crop parameters were independently calibrated with the observed crop data at six experimental stations. Then, sensitivity ranks of hydrological parameters were analysed, which suggested the important parameters used for calibration. The model was successfully calibrated using the monthly observed data of discharge in around 1970–1991 and actual ET (ETa) in 2002–2004 for the mountainous area and Haihe plain, respectively. Meanwhile, good agreements between the simulated and statistical crop yields in 1985–2005 further verified the model's appropriateness. Finally, the calibrated model was used to assess SWRs and ETa in time and space during 1961–2005. Results showed that the average annual natural SWRs and the ETa were about 17.5 billion cubic metre and 542 mm, respectively, both with a slight downward trend. The spatial distributions of both SWRs and ETa were significantly impacted by variations of precipitation and land use. Moreover, the reservoir in operation was the main factor for the noticeable decline of actual SWRs. In the Haihe plain, the ETa with irrigation was increased by 46% compared with that under rainfed conditions. In addition, this study identified the regions with potential to improve the irrigation effects on water use. Copyright © 2012 John Wiley & Sons, Ltd.
GENERALIZED AUTOREGRESSIVE SCORE MODELS WITH APPLICATIONS
Authors: Creal Drew , Koopman Siem Jan , Lucas André
Published: January 2012

We propose a class of observation‐driven time series models referred to as generalized autoregressive score (GAS) models. The mechanism to update the parameters over time is the scaled score of the likelihood function. This new approach provides a unified and consistent framework for introducing time‐varying parameters in a wide class of nonlinear models. The GAS model encompasses other well‐known models such as the generalized autoregressive conditional heteroskedasticity, autoregressive conditional duration, autoregressive conditional intensity, and Poisson count models with time‐varying mean. In addition, our approach can lead to new formulations of observation‐driven models. We illustrate our framework by introducing new model specifications for time‐varying copula functions and for multivariate point processes with time‐varying parameters. We study the models in detail and provide simulation and empirical evidence. Copyright © 2012 John Wiley & Sons, Ltd.
Freeze‐dried human serum albumin improves the adherence and proliferation of mesenchymal stem cells on mineralized human bone allografts
Authors: Weszl Miklós , Skaliczki Gábor , Cselenyák Attila , Kiss Levente , Major Tibor , Schandl Károly , Bognár Eszter , Stadler Guido , Peterbauer Anja , Csönge Lajos , Lacza Zsombor
Published: January 2012

Mineralized scaffolds are widely used as bone grafts with the assumption that bone marrow derived cells colonize and remodel them. This process is slow and often unreliable so we aimed to improve the biocompatibility of bone grafts by pre‐seeding them with human mesenchymal stem cells from either bone marrow or dental pulp. Under standard cell culture conditions very low number of seeded cells remained on the surface of freeze‐dried human or bovine bone graft or hydroxyapatite. Coating the scaffolds with fibronectin or collagen improved seeding efficiency but the cells failed to grow on the surface until the 18th day. In contrast, human albumin was a very potent facilitator of both seeding and proliferation on allografts which was further improved by culturing in a rotating bioreactor. Electron microscopy revealed that cells do not form a monolayer but span the pores, emphasizing the importance of pore size and microstructure. Albumin coated bone chips were able to unite a rat femoral segmental defect, while uncoated ones did not. Micro‐hardness measurements confirmed that albumin coating does not influence the physical characteristics of the scaffold, so it is possible to introduce albumin coating into the manufacturing process of lyophilized bone allografts. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:489–496, 2012
Mechanically induced calcium signaling in chondrocytes in situ
Authors: Han Sang‐Kuy , Wouters Wim , Clark Andrea , Herzog Walter
Published: January 2012

Changes in intracellular calcium (Ca2+) concentration, also known as Ca2+ signaling, have been widely studied in articular cartilage chondrocytes to investigate pathways of mechanotransduction. Various physical stimuli can generate an influx of Ca2+ into the cell, which in turn is thought to trigger a range of metabolic and signaling processes. In contrast to most studies, the approach used in this study allows for continuous real time recording of calcium signals in chondrocytes in their native environment. Therefore, interactions of cells with the extracellular matrix (ECM) are fully accounted for. Calcium signaling was quantified for dynamic loading conditions and at different temperatures. Peak magnitudes of calcium signals were greater and of shorter duration at 37°C than at 21°C. Furthermore, Ca2+ signals were involved in a greater percentage of cells in the dynamic compared to the relaxation phases of loading. In contrast to the time‐delayed signaling observed in isolated chondrocytes seeded in agarose gel, Ca2+ signaling in situ is virtually instantaneous in response to dynamic loading. These differences between in situ and in vitro cell signaling responses might provide crucial insight into the role of the ECM in providing pathways of mechanotransduction in the intact cartilage that are absent in isolated cells seeded in gel constructs. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:475–481, 2012
Compact dual‐mode bandpass filter using slotline resonator and stubs
Authors: Liu H. W. , Fan Y. C. , Wei G. W. , Xu W. Y. , Zhang Z. C. , Gui Z. P. , Huang D. C.
Published: January 2012

A compact elliptic‐function‐response bandpass filter using slotline resonators and stubs is designed in this letter. This slotline resonator is composed by one loop resonator with four corner‐patch perturbation and stubs. The nature of coupling between the degenerate modes is investigated with respect to the perturbation size. Also, slotline stubs are applied to miniature the filter's size by keeping excellent performance. Results verify that the central frequency and the fractional bandwidth of the proposed filter are 5.23 GHz and 7.45%, respectively. A good agreement between simulation and measurement verifies the validity of this design methodology. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:641–644, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26603
An improved multilevel simple sparse method with adaptive cross approximation for scattering from target above lossy half space
Authors: Hu Xiaoqing , Zhang Chi , Xu Yuan , Ding Dazhi , Chen Rushan
Published: January 2012

The adaptive cross approximation (ACA) algorithm has been used to reduce memory requirements and matrix‐vector product (MVP) time since it was proposed to solve electric field integral equation of electromagnetic problems. In this letter, we firstly introduce an improved multilevel simple sparse method (MLSSM). Based on the improved MLSSM, the impedance matrix resulting from ACA algorithm can be represented very sparsely. In the sparse representation, the far‐field interaction parts of impedance matrix can be represented by multiplication of three sparse matrices in recursive manner. Moreover, an efficient MVP operation is implemented by using the sparse representation. Numerical experiments demonstrate that our improved MLSSM with ACA algorithm outperforms original ACA algorithm in terms of memory requirement of far‐field interactions and the time per MVP operation. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:573–577, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26606
Design of a wideband 377 Ω E‐shaped patch antenna for RF energy harvesting
Authors: Devi Kavuri K. A. , Sadasivam S. , Din Norashidah Md. , Chakrabarthy C.K. , Rajib S. K.
Published: January 2012

The design of a 377 Ω E‐shaped patch antenna with partial ground plane is presented and discussed in this article. Two parallel slots are introduced into the conventional patch antenna, and it was investigated by the currents through the patch to enhance its bandwidth. The antenna is designed, fabricated, and measured for downlink frequency band of GSM 900, which shows an impedance bandwidth of 29.03% (277 MHz) at 954 MHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:569–573, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26607
Fiber bragg grating current sensor based on birefringence effect
Authors: Zhao Yong , Song Ting‐Ting
Published: January 2012

A novel DC current sensor configuration by combining the sensing theory of fiber Bragg grating (FBG) with the birefringence effect is proposed.Electromagnet force will occur when the measured current is applied due to the sensor configuration of a magnetic coil and a permanent magnet. A sensing FBG and a supporting fiber with the same diameter and material are inserted between two glass sheets. The electromagnet force will act on the glass sheets, resulting in a radial load on the sensing FBG. This transverse load will lead to the birefringence effect because of the different strain or refractive index variation of the two orthogonal axes of the sensing fiber. Thus, two orthogonal polarization modes will be reflected by the sensing FBG with different wavelengths. The theoretical model between Bragg wavelength shifts versus the applied current is derived. Preliminary experiments and simulation results show that current measurement sensitivity can reach 2 nm/A, and measurement resolution is about 0.5 mA. Cross‐sensitivity of temperature can be compensated by the differential method. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:822–826, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26609
Microstrip dual I‐band bandpass filter with symmetrical twin‐inductor resonators
Authors: Maharjan Ram Krishna , Kim Nam‐Young
Published: January 2012

A novel compact microstrip dual‐mode dual‐band bandpass filter using two symmetrical twin‐inductor resonators for I‐band application is proposed.Double twin symmetrical rectangular‐shaped inductors are connected with the stepped‐impedance resonator terminals for matching 50 Ω impedance. The two twin‐inductor ends are connected to ground with via connections. The two opposite inductors are joined and become twin‐inductor structure that also behaves as an inductor‐interdigital coupling. The combination of the two those twin‐inductor interdigital structures give strong inductive couplings between the two ports and develop a fixed resonance frequency. This filter is designed to operate at 8.1 GHz and 10.7 GHz resonant frequency with a 20.98 and 13.08% effective bandwidth, respectively, at the 3‐dB passband. More than 20 dB spurious suppression was measured in between two distinct bands. The measured insertion loss (S21) was less than 1 dB recorded for both bands and return loss (S11) was more than 21 dB measured at center operating frequencies of both bands. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:638–641, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26617
Compact and high selectivity triple‐band dual‐mode microstrip BPF with two short‐circuited stub‐loaded SIRs
Authors: Deng Hong‐wei , Liu Bing , Zhao Yong‐jiu , Chen Wen , Zhang Xue‐shun
Published: January 2012

In this letter, a compact and high selectivity triple‐band dual‐mode microstrip bandpass filter (BPF) is proposed using two short‐circuited stub‐loaded stepped‐impedance resonators (SIRs), which are same type but different size, that is, the SIR I and the SIR II with smaller size. The SIR I is designed to operate at the first and third passbands and the SIR II at the second passband. The passband frequencies can be conveniently tuned to desired values. Because of the intrinsic characteristics of the SIRs and the source–load coupling, six transmission zeros can be created to improve the selectivity of the triple‐band BPF. Finally, a filter prototype located at 1.57 (GPS application), 2.4, and 5.2 GHz (WLAN application) is designed, fabricated, and measured. The simulated and measured results are presented and an excellent agreement is obtained. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:719–721, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26654
Novel formulation of efficiency measure for multifilar transformers in generalized multiport configurations of integrated passive devices
Authors: Huang Chien‐Hsiang , Chen Chien‐Hsun , Horng Tzyy‐Sheng
Published: January 2012

This article formulates generalized transformer efficiency associated with the application of above‐IC multifilar transformers to multiport integrated passive devices (IPDs). The formulation derives the power‐loss ratio for a multifilar transformer in a multiport configuration based on a terminated microwave network, leading to the expression of passive efficiency using the concept of power conservation. For demonstration, the S‐parameters for several different types of three‐port transformers have been measured to compute their passive efficiency and, further, predict the minimum available insertion loss of three‐port IPDs such as baluns and combiners that use these three‐port transformers. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:656–661, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26656
Dual‐band bandstop frequency selective surfaces with gosper prefractal elements
Authors: Silva Paulo H. da F. , dos Santos Albanisa F. , Cruz Rossana M.S. , D'Assunção Adaildo G.
Published: January 2012

Self‐similarity property of Gosper island prefractals is exploited to design frequency selective surfaces (FSSs) for dual‐band bandstop filter operation. The use of Gosper prefractal patch elements enables the adjustment of FSS parameters (resonant frequency and −10 dB bandwidth) according to the number of fractal iterations but without modifying their original size. Transmission properties of proposed FSSs are characterized by means of simulations and measurements. Four FSS prototypes were fabricated and measured. The obtained results show an interesting dual‐band behavior. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:771–775, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26663
SET‐RAFT of MMA mediated by ascorbic acid‐activated copper oxide
Authors: Zhang Qin , Zhang Zhengbiao , Wang Wenxiang , Zhu Jian , Cheng Zhenping , Zhou Nianchen , Zhang Wei , Zhu Xiulin
Published: January 2012

In this work, cupric oxide (CuO) or cuprous oxide (Cu2O) was used as the catalyst for the single electron transfer‐reversible addition‐fragmentation chain transfer (SET‐RAFT) polymerization of methyl methacrylate in the presence of ascorbic acid at 25 °C. 2‐Cyanoprop‐2‐yl‐1‐dithionaphthalate (CPDN) was used as the RAFT agent. The polymerization occurred smoothly after an induction period arising from the slow activation of CuO (or Cu2O) and the “initialization” process in RAFT polymerization. The polymerizations conveyed features of “living”/controlled radical polymerizations: linear evolution of number‐average molecular weight with monomer conversion, narrow molecular weight distribution, and high retention of chain end fidelity. From the polymerization profile, it was deduced that the polymerization proceeded via a conjunct mechanism of single electron transfer‐living radical polymerization (SET‐LRP) and RAFT polymerization, wherein CPDN acting as the initiator for SET‐LRP and chain transfer agent for RAFT polymerization. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Clarithromycin therapy for patients with Cystic Fibrosis: A randomized controlled trial
Authors: Robinson P. , Schechter Michael S. , Sly Peter D. , Winfield Kaye , Smith Julie , Brennan Siobhain , Shinkai Masaharu , Henke Markus O. , Rubin Bruce K.
Published: January 2012

The clinically significant actions of oral azithromycin in modifying progressive cystic fibrosis (CF) lung disease have been well documented. In vitro and clinical data suggests that clarithromycin has immunomodulatory properties similar to other 14‐member macrolides, however two previously reported short term, open label trials of clairthromycin in small numbers of patients with CF failed to show significant benefits in modifying lung function or inflammation. We performed an international double blind, cross‐over trial in which 63 subjects with CF were studied while receiving either placeo or 500 mg oral clarithromycin twice daily for 5 months, with a 1‐month wash‐out. The primary efficacy end point was the change in lung function (FEV1 and FVC) during the clarithromycin treatment period compared to placebo treatment. Secondary efficacy end points included; quality of life, number of pulmonary exacerbations, height and weight, sputum inflammatory mediator content, sputum transportability and surface properties, bacterial flora, nasal potential difference, and breath condensate. No significant difference in either the primary efficacy end point or any secondary end point was seen during the period of clarithromycin treatment compared to those seen during placebo administration. We conclude that clarithromycin is not effective in treating CF lung disease. Pediatr Pulmonol. 2012; 47:551–557. © 2012 Wiley Periodicals, Inc.
L2 stability, H∞ control of switched homogeneous nonlinear systems and their semi‐tensor product of matrices representation
Authors: Zhang Lijun , Zhang Kuize
Published: January 2012

This paper investigates the problems of L2 stability and H∞ control of switched homogeneous nonlinear systems. This paper gives that if a switched homogeneous nonlinear system with disturbance is internally homogeneously asymptotically stable, then it has a finite L2 gain, and if a switched homogeneous nonlinear system with disturbance and controls is homogeneously stabilizable under the zero disturbance condition, its H∞ control problem is solvable under some mild conditions, and a homogeneous solution is given. Then, via the semi‐tensor product of matrices method, the aforementioned obtained results are transformed to linear‐like forms, and the aforementioned obtained Hamilton–Jacobi–Isaacs inequality is transformed to a linear‐like matrix inequality, which makes it feasible to compute the solutions by computer. Copyright © 2012 John Wiley & Sons, Ltd.