bluuebunny/crossref_metadata_2025 huggingface dataset:
Early-Stage Precipitation Phenomena and Composition-Dependent Hardening in Al-Mg-Si-(Cu) Alloys
Authors: Fallah Vahid , Korinek Andreas , Raeisinia Babak , Gallerneault Mark , Esmaeili Shahrzad
Published: June 2014

Al-Mg-Si-(Cu), i.e. AA6xxx, alloys are widely used light alloys which can be effectively strengthened through precipitation hardening. The final microstructure, and thus properties, of these alloys after common artificial aging treatments are largely determined by the composition-dependent nano-scale clustering and precipitation that occur during the earliest stage of aging. Therefore, multi-length scale analysis of the earliest-stage of precipitation can provide critical knowledge in understanding the basis for the microstructural evolution during aging and attaining the desired microstructures and properties. Here, we investigate the effect of alloy composition on the evolution of early-stage clusters and precipitates during aging at 180°C using high resolution transmission electron microscopy. The results map a sequential evolution of clusters with an FCC structure but different morphology/orientation characteristics. GP-zones with structures other than FCC, also form in the early stages of aging. The composition-dependent kinetics of β” phase precipitation and hardening behavior are discussed in light of the results from differential scanning calorimetry experiments, microhardness measurements, and conventional transmission electron microscopy.
The Influence of Mg and Ag on the Precipitation Kinetics and the Formation of the T1 Phase in Al-Cu-Li Alloys
Authors: Gumbmann Eva , de Geuser Frederic , Lefebvre Williams , Sigli Christophe , Deschamps Alexis
Published: June 2014

Al-Cu-Li alloys are extensively used for aerospace applications. The main hardening phase is the T1 phase that precipitates as thin platelets on {111}Al planes. To facilitate its nucleation, different minor alloying elements are added and dislocations are introduced by cold deformation before the ageing treatment. The impact of these additions in combination with the presence of dislocations on precipitate nucleation and growth needs a deeper understanding. In this work, we investigated the precipitation kinetics of the T1 phase in alloys containing a common content of Cu and Li and different contents of minor solutes (Mg, Ag) where these elements are present either together or independently. A general overview on the precipitation kinetics was achieved by in-situ small-angle X-ray scattering and hardness measurements. The evaluation of precipitation kinetics reveals that magnesium plays an important role during precipitation by enhancing nucleation kinetics. Additionally, a smaller yet measureable effect of Ag, both in the presence and absence of Mg has been evidenced.
Ageing Characteristics of Al-Mg-(Ge,Si)-Cu Alloys
Authors: Liu Meng , Marioara Calin Daniel , Holmestad Randi , Banhart John
Published: June 2014

In order to elucidate some of the differences between Al-Mg-Si and Al-Mg-Ge alloys and the role of Cu, a series of Al-Mg-Ge, Al-Mg-Si and Al-Mg-Ge-Si alloys, some of them containing Cu, are investigated by positron annihilation lifetime spectroscopy during natural ageing. Al-Mg-Ge alloys show qualitatively the same evolution of positron lifetime τ1C with time as Al-Mg-Si alloys, namely an initial decrease, followed by a re-increase, after which τ1C drops to an equilibrium value. However, for alloys with equal Mg contents, Ge gives rise to a notably slower ageing kinetics than Si, pointing at effects of atomic size or solute-vacancy binding energies. Adding Cu to both Al-Mg-Ge and Al-Mg-Si alloys slows down the initial formation of clusters but promotes their further growth.
Observation of large Equilibrium Phase of Al-Mg-Si Alloys
Authors: Hida Shintaro , Mikmeková Šárka , Matsuda Kenji , Ikeno Susumu
Published: June 2014

The precipitation sequence in Al-Mg-Si alloy is generally accepted as supersaturated solid solution GP-zone β β β (Mg2Si). The effect of Ag or Cu in Al-Mg-Si alloy was reported in our previous work. There is little report about effect of Ag or Cu on the metastable phase and equilibrium phase in this alloy the system. Hexagonal plate like β-phase and Q-phase were observed the Cu added alloy. This hexagonal-shaped β-phase has unique orientation relationship to the Al matrix. This work was performed to compare the shape of effect of the additional elements on the equilibrium phase. The hexagonal shape precipitate was observed in Cu or Ag added alloys aged at 673K.
The Ground State of Innate Immune Responsiveness Is Determined at the Interface of Genetic, Epigenetic, and Environmental Influences
Authors: Huang Edward , Wells Christine Anne
Published: June 2014

Monocytes and macrophages form the major cellular component of the innate immune system, with roles in tissue development, homeostasis, and host defense against infection. Environmental factors were shown to play a significant part in determining innate immune responsiveness, and this included systemic conditions, such as circulating glucose levels, gut microflora, time of year, and even diurnal rhythm, which had a direct impact on innate immune receptor expression. Although the underlying molecular processes are just beginning to emerge, it is clear that environmental factors may alter epigenetic states of peripheral blood monocytes and resident tissue macrophages. We conclude that some measure of cellular ground state must become an essential part of the analysis of myeloid responsiveness or infectious susceptibility.
A fuzzy-based model to implement the global safety buildings index assessment for agri-food buildings
Authors: Barreca Francesco , Cardinali Giuseppe , Fichera Carmelo Riccardo , Lamberto Luigi , Modica Giuseppe
Published: June 2014

The latest EU policies focus on the issue of food safety with a view to ensuring adequate and standard quality levels for the food produced and/or consumed within the EC. To that purpose, the environment where agricultural products are manufactured and processed plays a crucial role in achieving food hygiene. As a consequence, it is of the outmost importance to adopt proper building solutions which meet health and hygiene requirements as well as to use suitable tools to measure the levels achieved. Similarly, it is necessary to verify and evaluate the level of workers’ safety and welfare in their working environment. Workers’ safety has not only an ethical and social value but also an economic implication, since possible accidents or environmental stressors are the major causes of the lower efficiency and productivity of workers. Therefore, it is fundamental to design suitable models of analysis that allow assessing buildings as a whole, taking into account both health and hygiene safety as well as workers’ safety and welfare. Hence, this paper proposes an assessment model that, based on an established study protocol and on the application of a fuzzy logic procedure, allows assessing the global safety level of an agri-food building by means of a global safety buildings index. The model here presented is original since it uses fuzzy logic to evaluate the performances of both the technical and environmental systems of an agri-food building in terms of health and hygiene safety of the manufacturing process as well as of workers’ health and safety. The result of the assessment is expressed through a triangular fuzzy membership function which allows carrying out comparative analyses of different buildings. A specific procedure was developed to apply the model to a case study which tested its operational simplicity and the validity of its results. The proposed model allows obtaining a synthetic and global value of the building performance of each of its functional areas, in terms of food hygiene and workers’ safety and welfare, as well as highlighting possible weaknesses. Though the model may be applied in either the design or the operational phase of a building, this paper focuses on its application to certain buildings already operating in a specific productive context.
Productivity and quality performance of an innovative firewood processor
Authors: Cavalli Raffaele , Grigolato Stefano , Sgarbossa Andrea
Published: June 2014

The growing interest about wood as fuel regards not only wood chips and pellets but also firewood, especially in mountain and rural areas where domestic heating plants are widely used. Due to the increased demand for firewood, harvesting activities have extended on broadleaved high forests as well as coppice. As a consequence, the diameter of logs has increased requiring larger and larger splitting machines; nowadays it is not uncommon to find on the market splitters able to process logs with diameter up to 50-60 cm. In order to increase the productivity, the effort of machine producers is directed to obtain the complete splitting of the log into firewood in only one step using multiple ways splitting knives. This technical solution may cause some drawbacks especially when the splitting knives are not properly adapted to the log diameter; it happens that the size of firewood is not homogeneous and splinters are produced, which requires using screens to separate them from the main product. In order to evaluate the work quality of a firewood processor, equipped with multiple ways splitting knives, an experimental test has been carried out using a machine in which the log diameter is automatically detected through a laser device; according to the log diameter the multiple ways splitting knives (formed by fixed and mobile knives, the latter hydraulically operated) is properly set up to obtain regularly sized firewood. Furthermore the log is automatically centred on the splitting knife set-up. The results of the experimental test showed that the firewood processor is able to produce firewood with homogeneous size and with a low production of splinters, regardless of log diameter.
The early Korean Protestant Churches’ impact on Korea’s democratisation: With special reference to the Korean Presbyterian Church
Authors: Hwang Jae-Buhm
Published: June 2014

This study examines the significant influence of the early Korean Protestant churches in general and the Korean Presbyterian Church in particular on the early phases of Korea’s democratisation. Firstly, the Western Protestant mission works in general were visibly conducive for dissemination and cultivation of egalitarian and democratic ideals, with the mission churches becoming sites of do-it-yourself democracy. Secondly, the Nevius (Mission) Methods of the Korean Presbyterian Church came to foster the democratic spirit of self-support and self-government, resulting in its rapid growth. Thirdly, with the implementation of a nationwide, representative and democratic polity (presbytery) with a constitution, the church even facilitated law-binding and institutional democracy for Koreans in general and Korean Christians in particular. Fourthly, the church’s democratic working deeply inspired Korean democratic politicians, especially Mr Changho Ahn, who had an important influence on the making of the Provisional Government of Korea and its Constitution.
Persistent hyperplastic primary vitreous – The martini glass sign
Authors: Bezuidenhout Fourie A.
Published: June 2014

No abstract.
Impact of data quality and surface-to-column representativeness on the PM2.5 / satellite AOD relationship for the contiguous United States
Authors: Toth T. D. , Zhang J. , Campbell J. R. , Hyer E. J. , Reid J. S. , Shi Y. , Westphal D. L.
Published: June 2014

Abstract. Satellite-derived aerosol optical depth (AOD) observations have been used to estimate particulate matter smaller than 2.5 μm (PM2.5). However, such a relationship could be affected by the representativeness of satellite-derived AOD to surface aerosol particle mass concentration and satellite AOD data quality. Using purely measurement-based methods, we have explored the impacts of data quality and representativeness on the AOD-inferred PM2.5 / AOD relationship for the contiguous United States (CONUS). This is done through temporally and spatially collocated data sets of PM2.5 and AOD retrievals from Aqua/Terra Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging Spectroradiometer (MISR), and Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). These analyses show that improving data quality of satellite AOD, such as done with data assimilation-grade retrievals, increases their correlation with PM2.5. However, overall correlation is relatively low across the CONUS. Also, integrated extinction observed within 500 m above ground level (a.g.l.), as measured by CALIOP, is not well representative of the total column AOD. Surface aerosol in the eastern CONUS is better correlated with total column AOD than in the western CONUS. The best correlation values are found for estimated dry mass CALIOP extinction at 200–300 m a.g.l. and PM2.5, but additional work is needed to address the ability of using actively sensed AOD as a proxy for PM2.5 concentrations.
Functional characterization of the water-soluble organic carbon of size-fractionated aerosol in the southern Mississippi Valley
Authors: Chalbot M.-C. G. , Brown J. , Chitranshi P. , Gamboa da Costa G. , Pollock E. D. , Kavouras I. G.
Published: June 2014

Abstract. The chemical content of water-soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for periods when carbonaceous aerosol was the most abundant particulate component. The WSOC accounted for 5% of particle mass for particles with dp > 0.96 μm and 10% of particle mass for particles with dp < 0.96 μm. Non-exchangeable aliphatic (H–C), unsaturated aliphatic (H–C–C=), oxygenated saturated aliphatic (H–C–O), acetalic (O–CH–O) and aromatic (Ar–H) protons were determined by proton nuclear magnetic resonance (1H-NMR). The total non-exchangeable organic hydrogen concentrations varied from 4.1 ± 0.1 nmol m−3 for particles with 1.5 < dp < 3.0 μm to 73.9 ± 12.3 nmol m−3 for particles with dp < 0.49 μm. The molar H / C ratios varied from 0.48 ± 0.05 to 0.92 ± 0.09, which were comparable to those observed for combustion-related organic aerosol. The R–H was the most abundant group, representing about 45% of measured total non-exchangeable organic hydrogen concentrations, followed by H–C–O (27%) and H–C–C= (26%). Levoglucosan, amines, ammonium and methanesulfonate were identified in NMR fingerprints of fine particles. Sucrose, fructose, glucose, formate and acetate were associated with coarse particles. These qualitative differences of 1H-NMR profiles for different particle sizes indicated the possible contribution of biological aerosols and a mixture of aliphatic and oxygenated compounds from biomass burning and traffic exhausts. The concurrent presence of ammonium and amines also suggested the presence of ammonium/aminium nitrate and sulfate secondary aerosol. The size-dependent origin of WSOC was further corroborated by the increasing δ13C abundance from −26.81 ± 0.18‰ for the smallest particles to −25.93 ± 0.31‰ for the largest particles and the relative distribution of the functional groups as compared to those previously observed for marine, biomass burning and secondary organic aerosol. The latter also allowed for the differentiation of urban combustion-related aerosol and biological particles. The five types of organic hydrogen accounted for the majority of WSOC for particles with dp > 3.0 μm and dp < 0.96 μm.
Variations of ground-level O3 and its precursors in Beijing in summertime between 2005 and 2011
Authors: Zhang Q. , Yuan B. , Shao M. , Wang X. , Lu S. , Lu K. , Wang M. , Chen L. , Chang C.-C. , Liu S. C.
Published: June 2014

Abstract. Elevated ground-level ozone (O3), reflecting atmospheric oxidative capacity, are of increasing concern. High levels of total oxidants (Ox= O3 + NO2) have been persistently observed as a feature of Beijing's air pollution. Beijing is a well-known megacity requiring the enforcement of stringent air quality controls as rapid economic growth continues. To evaluate the effect of air quality controls in recent years, ground-based on-line measurements at an urban site were conducted in summer and the variations in O3 with simultaneous changes in NOx and volatile organic compounds (VOCs) between 2005 and 2011 were analyzed. Both NOx and total VOCs in Beijing decreased over the study period, 1.4 ppbv yr−1 and 1.6 ppbv yr−1, respectively. However, VOCs reactivity, in terms of OH loss rate, showed an indistinct statistical trend due to unsteady variations from naturally emitted isoprene, though some anthropogenic species showed decreasing trends, such as pentane, benzene and toluene. Meanwhile, daytime average O3 increased rapidly at an annual rate of 2.6 ppbv yr−1, around 5% yr−1 between 2005 and 2011. Considering the influence of NO titration effect and elevated regional ozone background in the North China Plain (NCP), the main reason for such an increase in oxidants was subject to "local" photochemistry. A simplified model was used to evaluate the effect of changes in the levels of ozone precursors on ozone production. We found that between 2001 and 2006, the production rate of total oxidants, P(Ox) increased rapidly due to increased VOC levels and decreasing NO2, while from 2006 to 2011 P(Ox) remained high, though decreased slightly as a consequence of the decrease in both VOC reactivity (−5% yr−1) and NOx (−4% yr−1). Observations have shown that Beijing's efforts to control air pollution were somehow effective in cutting ozone precursors, but still left higher ground-level ozone. We surmised that it resulted from potential contributions from OVOCs and regional transport near Beijing. Therefore, Beijing needs deeper cooperation with adjacent provinces to control ozone pollution together. To impel this kind of joint prevention and control program, ground-level ozone should become a mandatory index for air quality management, and a faster reduction of VOCs, especially reactive VOCs, in urban areas, should coordinate with national NOx emission control programs.
Effect of water vapor on the determination of aerosol direct radiative effect based on the AERONET fluxes
Authors: Huttunen J. , Arola A. , Myhre G. , Lindfors A. V. , Mielonen T. , Mikkonen S. , Schafer J. S. , Tripathi S. N. , Wild M. , Komppula M. , Lehtinen K. E. J.
Published: June 2014

Abstract. The aerosol direct radiative effect (ADRE) is defined as the change in the solar radiation flux, F, due to aerosol scattering and absorption. The difficulty in determining ADRE stems mainly from the need to estimate F without aerosols, F0, with either radiative transfer modeling and knowledge of the atmospheric state, or regression analysis of radiation data down to zero aerosol optical depth (AOD), if only F and AOD are observed. This paper examines the regression analysis method by using modeled surface data products provided by the Aerosol Robotic Network (AERONET). We extrapolated F0 by two functions: a straight linear line and an exponential nonlinear decay. The exponential decay regression is expected to give a better estimation of ADRE with a few percent larger extrapolated F0 than the linear regression. We found that, contrary to the expectation, in most cases the linear regression gives better results than the nonlinear. In such cases the extrapolated F0 represents an unrealistically low water vapor column (WVC), resulting in underestimation of attenuation caused by the water vapor, and hence too large F0 and overestimation of the magnitude of ADRE. The nonlinear ADRE is generally 40–50% larger in magnitude than the linear ADRE due to the extrapolated F0 difference. Since for a majority of locations, AOD and WVC have a positive correlation, the extrapolated F0 with the nonlinear regression fit represents an unrealistically low WVC, and hence too large F0. The systematic underestimation of F0 with the linear regression is compensated by the positive correlation between AOD and water vapor, providing the better result.
The impact of aerosol hygroscopic growth on the single-scattering albedo and its application on the NO2 photolysis rate coefficient
Authors: Tao J. C. , Zhao C. S. , Ma N. , Liu P. F.
Published: June 2014

Abstract. Hygroscopic growth of aerosol particles can significantly affect their single-scattering albedo (ω), and consequently alters the aerosol effect on tropospheric photochemistry. In this study, the impact of aerosol hygroscopic growth on the ω and its application on NO2 photolysis rate coefficient (JNO2) are investigated for a typical aerosol particle population in the North China Plain (NCP). The variations of aerosol optical properties with relative humidity (RH) are calculated using a Mie-theory aerosol optical model, on the basis of field measurements of number size distribution and hygroscopic growth factor from 2009 HaChi (Haze in China) project. Results demonstrate that ambient ω has pronounced diurnal patterns and is highly sensitive to the ambient RHs. Ambient ω in the NCP can be described by a dry state ω value of 0.863, increasing with the RH following a characteristic RH dependence curve. The Monte Carlo simulation shows that the uncertainty of ω from the propagation of uncertainties in the input parameters decreases from 0.03 (at dry state) to 0.01 (RHs > 90%). The impact of hygroscopic growth on ω is further applied in the calculation of the radiative transfer process. Hygroscopic growth of the studied aerosol particle population generally inhibits the photolysis of NO2 at the ground level, whereas accelerates it above the upper boundary layer. Compared with dry state, the calculated JNO2 at RH of 98% at the height of 1 km increases by 30.4%, because of the enhancement of ultraviolet radiation by the humidified scattering-dominant aerosol particles. The increase of JNO2 due to the aerosol hygroscopic growth above the upper boundary layer may affect the tropospheric photochemical processes and this needs to be taken into account in the atmospheric chemical models.
Measurements of diurnal variations and Eddy Covariance (EC) fluxes of glyoxal in the tropical marine boundary layer: description of the Fast LED-CE-DOAS instrument
Authors: Coburn S. , Ortega I. , Thalman R. , Blomquist B. , Fairall C. W. , Volkamer R.
Published: June 2014

Abstract. Here we present first Eddy Covariance (EC) measurements of fluxes of glyoxal, the smallest α-dicarbonyl product of hydrocarbon oxidation, and a precursor for secondary organic aerosol (SOA). The unique physical and chemical properties of glyoxal, i.e., high solubility in water (Henry's Law constant, KH = 4.2 × 105 M atm−1) and short atmospheric lifetime (~2 h at solar noon) make it a unique indicator species for organic carbon oxidation in the marine atmosphere. Previous reports of elevated glyoxal over oceans remain unexplained by atmospheric models. Here we describe a Fast Light Emitting Diode Cavity Enhanced Differential Optical Absorption Spectroscopy (Fast LED-CE-DOAS) instrument to measure diurnal variations and EC fluxes of glyoxal, and inform about its unknown sources. The fast in situ sensor is described, and first results are presented from a cruise deployment over the Eastern tropical Pacific Ocean (20° N to 10° S; 133° W to 85° W) as part of the Tropical Ocean Troposphere Exchange of Reactive Halogens and OVOC (TORERO) field experiment (January to March 2012). The Fast LED-CE-DOAS is a multispectral sensor that selectively and simultaneously measures glyoxal (CHOCHO), nitrogen dioxide (NO2), oxygen dimers (O4) and water vapor (H2O) with ~2 Hz time resolution, and a precision of ~40 pptv Hz−0.5 for glyoxal. The instrument is demonstrated to be a "white-noise" sensor suitable for EC flux measurements; further, highly sensitive and inherently calibrated glyoxal measurements are obtained from temporal averaging of data (~2 pptv detection limit over 1 h). The campaign averaged mixing ratio in the Southern Hemisphere (SH) is found to be 43 ± 9 pptv glyoxal, and is higher than in the Northern Hemisphere (NH: 32 ± 6 pptv; error reflects variability over multiple days). The diurnal variation of glyoxal in the MBL is measured for the first time, and mixing ratios vary by ~8 ppt (NH) and ~12 pptv (SH) over the course of 24 h. Consistently, maxima are observed at sunrise (NH: 35 ± 5 pptv; SH: 47 ± 7 pptv) and minima at dusk (NH: 27 ± 5 pptv; SH: 35 ± 8 pptv). Ours are the first EC flux measurements of glyoxal. In both hemispheres, the daytime flux was directed from the atmosphere into the ocean, indicating that the ocean is a net sink for glyoxal during the day. After sunset the ocean was a source for glyoxal to the atmosphere (positive flux) in the SH; this primary ocean source was operative throughout the night. In the NH, the nighttime flux was positive only shortly after sunset, and negative during most of the night. Positive EC fluxes of soluble glyoxal over oceans indicate the presence of an ocean surface organic microlayer (SML), and locate a glyoxal source within the SML. The origin of atmospheric glyoxal, and possibly other oxygenated hydrocarbons over tropical oceans warrants further investigation.
Forest conversion to poplar plantation in a Lombardy floodplain (Italy): effects on soil organic carbon stock
Authors: Ferré C. , Comolli R. , Leip A. , Seufert G.
Published: June 2014

Abstract. Effects of forest conversion to poplar plantation on soil organic carbon (SOC) stocks were investigated by sampling paired plots in an alluvial area of the Ticino river in Northern Italy. According to land registers and historical aerial photographs, the two sites were part of a larger area of a 200 years-old natural forest that was partly converted to poplar plantation in 1973. The soil sampling of three layers down to a depth of 100 cm was performed at 90 and 70 points in the natural forest (NF) and in the nearby poplar plantation (PP), respectively. The substitution of the natural forest with the poplar plantation strongly modified soil C stock down to a depth of 55 cm, although the management practices at PP were not intensive. By evaluation of equivalent soil masses, the comparison of C stocks (organic layer included) between the different land uses showed a decrease in SOC of 5.7 kg m−2 after 37 years of poplar cultivation, corresponding to more than 1/3 of the initial organic carbon content. The land use change from NF to PP not only affected the stock but also the vertical distribution of SOC: ploughing led to the transfer of SOC from soil surface into the deeper layers resulting in a more uniform allocation of organic carbon in the ploughed layer and disappearance of the SOC stratification observed in the forest.
Evaluating Southern Ocean biological production in two ocean biogeochemical models on daily to seasonal time-scales using satellite surface chlorophyll and O2/Ar observations
Authors: Jonsson B. F. , Doney S. , Dunne J. , Bender M. L.
Published: June 2014

Abstract. We assess the ability of ocean biogeochemical models to represent seasonal structures in biomass and net community production (NCP) in the Southern Ocean. Two models are compared to observations on daily to seasonal time scales in four different sections of the region. We use daily satellite fields of Chlorophyll (Chl) as a proxy for biomass, and in-situ observations of O2 and Ar supersaturation (ΔO2Ar) to estimate NCP. ΔO2Ar is converted to the flux of biologically generated O2 from sea to air ("O2 bioflux"). All data are aggregated to a climatological year with a daily resolution. To account for potential regional differences within the Southern Ocean, we conduct separate analyses of sections south of South Africa, around the Drake Passage, south of Australia, and south of New Zealand. We find that the models simulate the upper range of Chl concentrations well, underestimate spring levels significantly, and show differences in skill between early and late parts of the growing season. While there is a great deal of scatter in the bioflux observations in general, the four sectors each have distinct patterns that the models pick up. Neither model exhibit a significant distinction between the Australian and New Zealand sectors, and between the Drake Passage and African sectors. South of 60° S, the models fail to predict the observed extent of biological O2 undersaturation. We suggest that this shortcoming may be due either to problems with the ecosystem dynamics or problems with the vertical transport of oxygen. Overall, the bioflux observations are in general agreement with the seasonal structures in satellite chlorophyll, suggesting that this seasonality represent changes in carbon biomass and not Chl : C ratios. This agreement is shared in the models and allows us to interpret the seasonal structure of satellite chlorophyll as qualitatively reflecting the integral of biological production over time for the purposes of model assessment.
Soil properties and pre-Columbian settlement patterns in the Monumental Mounds Region of the Llanos de Moxos, Bolivian Amazon
Authors: Lombardo U. , Denier S. , Veit H.
Published: June 2014

Abstract. In the present paper we explore to what degree soil properties might have influenced pre-Columbian settlement patterns in the Monumental Mounds Region (MMR) of the Llanos de Moxos (LM), Bolivian Amazon. Monumental mounds are pre-Hispanic earth buildings and were preferentially built on mid to late Holocene paleo levees of the Grande River (here denominated PR1), while levees of older paleorivers (PR0) were only sparsely occupied. We dug two transects across PR0 and PR1 levee-backswamp catenas and analysed them for grain size, pH, CEC and Corg. Our data show that PR1 soils, where the density of mounds is higher, have far greater agricultural potential than PR0 soils, which are affected by aluminium toxicity in the backswamps and by high levels of exchangeable sodium in the levees. This study provides new data on the soil properties of the south-eastern Bolivian Amazon and reinforces the thesis that environmental constraints and opportunities exerted an important role on pre-Columbian occupation patterns and the population density reached in the Bolivian Amazon.
Bomb dating, age validation and quality control of age determinations of monodontids and other marine mammals
Authors: Campana Steven E , Stewart Robert EA
Published: June 2014

Methods for confirming the accuracy of age determination methods are reasonably well established in fishes, but the millions of routine age determinations which take place every year require their own quality control protocols. In contrast, methods for ensuring accuracy in age determination of monodontids and other marine mammals are still being developed. Here we review the basis and application of bomb radiocarbon to marine mammal age validation, highlighting its value for providing unambiguous estimates of age for belugas and other long-lived animals which form growth bands. Bomb radiocarbon is particularly useful for marine mammals, given that the age of an individual animal can be determined to within ±1-3 years, as long as it was alive during the 1960s. However, ongoing age determinations require careful monitoring to ensure that age interpretations remain consistent across ages and through time. Quality control protocols using reference collections of ageing material, in conjunction with age bias plots and measures of precision, are capable of detecting virtually all of the systematic ageing errors that often occur once age determinations of an animal become routine.
Scale‐dependent energy conservation and its connection to flow field instability in porous media
Authors: Deinert M. R.
Published: June 2014

It has been known for decades that isothermal flow fields in porous media can become unstable, resulting in the growth of preferential flow paths and nonmonotonic moisture profiles. The standard approach to modeling isothermal fluid transport in a porous systems is to use Richards equation with equilibrium relationships for the driving potential and monotonic transport coefficients. However, it is well known that under these conditions, solutions to Richards' equation are unconditionally stable. This has left open the question of whether Richards' equation could predict the onset of flow field instability, and what is required to model it. Importantly, past work has shown that pore scale processes can actually cause nonequilibrium driving potentials to arise in unsaturated media. How these can lead to flow field instability can be understood using a form of spectral perturbation theory. Here the driving potential is represented using a Fourier expansion, which is then substituted into Richards equation. The result shows that the evolution of perturbations to the flow field are affected by the interaction between different wavelength components in the Fourier expansion. In particular, there are situations where nonequilibrium driving potentials can set up conditions that would allow the onset of instability in solutions to Richards' equation.
Understanding Lattice Strain‐Controlled Charge Transport in Organic Semiconductors: A Computational Study
Authors: Zheng Xiaoyan , Geng Hua , Yi Yuanping , Li Qikai , Jiang Yuqian , Wang Dong , Shuai Zhigang
Published: June 2014

The softness and anisotropy of organic semiconductors offer unique properties. Recently, solution‐sheared thin‐films of 6,13‐bis(triisopropylsilylethynyl) pentacene (TIPS‐P) with nonequilibrium single‐crystal domains have shown much higher charge mobilities than unstrained ones (Nature2011, 480, 504). However, to achieve efficient and targeted modulation of charge transport in organic semiconductors, a detailed microscopic understanding of the structure–property relationship is needed. In this work, motivated by the experimental studies, the relationship between lattice strain, molecular packing, and charge carrier mobility of TIPS‐P crystals is elucidated. By employing a multiscale theoretical approach combining nonequilibrium molecular dynamics, first‐principles calculations, and kinetic Monte Carlo simulations using charge‐transfer rates based on the tunneling enabled hopping model, charge‐transport properties of TIPS‐P under various lattice strains are investigated. Shear‐strained TIPS‐P indeed exhibits one‐dimensional charge transport, which agrees with the experiments. Furthermore, either shear or tensile strain lead to mobility enhancement, but with strong charge‐transport anisotropy. In addition, a combination of shear and tensile strains could not only enhance mobility, but also decrease anisotropy. By combining the shear and tensile strains, almost isotropic charge transport could be realized in TIPS‐P crystal with the hole mobility improved by at least one order of magnitude. This approach enables a deep understanding of the effect of lattice strain on charge carrier transport properties in organic semiconductors.
ScFv‐Decorated PEG‐PLA‐Based Nanoparticles for Enhanced siRNA Delivery to Her2+ Breast Cancer
Authors: Dou Shuang , Yang Xian‐Zhu , Xiong Meng‐Hua , Sun Chun‐Yang , Yao Yan‐Dan , Zhu Yan‐Hua , Wang Jun
Published: June 2014

Patients with Her2‐overexpressing (Her2+) breast cancers generally have a poorer prognosis due to the high aggressiveness and chemoresistance of the disease. Small interfering RNA (siRNA) targeting the gene encoding polo‐like kinase 1 (Plk1; siPlk1) has emerged as an efficient therapeutic agent for Her2+ breast cancers. Poly(ethylene glycol)‐block‐poly(d,l‐lactide) (PEG‐PLA)‐based nanoparticles for siRNA delivery were previously developed and optimized. In this study, for targeted delivery of siPlk1 to Her2+ breast cancer, anti‐Her2 single‐chain variable fragment antibody (ScFvHer2)‐decorated PEG‐PLA‐based nanoparticles with si Plk1 encapsulation (ScFvHer2‐NPsi Plk1) are developed. With the rationally designed conjugation site, ScFvHer2‐NPsiRNA can specifically bind to the Her2 antigen overexpressed on the surface of Her2+ breast cancer cells. Therefore, ScFvHer2‐NPsi Plk1 exhibits improved cellular uptake, promoted Plk1 silencing efficiency, and induced enhanced tumor cell apoptosis in Her2+ breast cancer cells, when compared with nontargeted NPsi Plk1. More importantly, ScFvHer2‐NPsiRNA markedly enhances the accumulation of siRNA in Her2+ breast tumor tissue, and remarkably improves the efficacy of tumor suppression. Dose‐dependent anti‐tumor efficacy further demonstrates that ScFvHer2‐decorated PEG‐PLA‐based nanoparticles with siPlk1 encapsulation can significantly enhance the inhibition of Her2+ breast tumor growth and reduce the dose of injected siRNA. These results suggest that ScFvHer2‐decorated PEG‐PLA‐based nanoparticles show great potential for targeted RNA interference therapy of Her2+ breast tumor.
Modular Hydroxyamide and Thioamide Pyranoside‐Based Ligand Library from the Sugar Pool: New Class of Ligands for Asymmetric Transfer Hydrogenation of Ketones
Authors: Coll Mercè , Pàmies Oscar , Diéguez Montserrat
Published: June 2014

A large library of pyranoside‐based hydroxyamide and thioamide ligands has been synthesized for asymmetric transfer hydrogenation in an attempt to expand the scope of the substrates to cover a broader range of challenging heteroaromatic and aryl/fluoroalkyl ketones. These ligands have the advantage that they are prepared from commercial D‐glucose, D‐glucosamine and α‐amino acids, inexpensive natural chiral feedstocks. By carefully selecting the ligand components (substituents/configurations at the amide/thioamide moiety, the position of amide/thioamide group and the configuration at C‐2), we found that pyranoside‐based thioamide ligands provided excellent enantioselectivities (in the best cases, ees of >99% were achieved) in a broad range of ketones, including the less studied heteroaromatics and challenging aryl/fluoroalkyls. Note that both enantiomers of the reduction products can be obtained with excellent enantioselectivities by simply changing the absolute configuration of the thioamide substituent.

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Synthesis of Polyacrylonitrile Fiber‐Supported Poly(ammonium methanesulfonate)s as Active and Recyclable Heterogeneous Brønsted Acid Catalysts
Authors: Shi Xian‐Lei , Xing Xiaoli , Lin Huikun , Zhang Wenqin
Published: June 2014

A new polyacrylonitrile fiber‐supported Brønsted acid catalyst has been developed and verified to efficiently (high yield, 10 cycles) mediate Biginelli reactions in ethanol, Pechmann condensations in toluene, Friedel–Crafts alkylations of indoles in water and conversion of fructose in dimethyl sulfoxide (DMSO) and mixed‐aqueous system.

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Continuous Synthesis of Organozinc Halides Coupled to Negishi Reactions
Authors: Alonso Nerea , Miller L. Zane , de M. Muñoz Juan , Alcázar Jesus , McQuade D. Tyler
Published: June 2014

The Negishi cross‐coupling is a powerful CC bond forming reaction. The method is less commonly used relative to other cross‐coupling methods in part due to lack of availability of organozinc species. While organozinc species can be prepared, problems with reproducibility and handling of these sensitive species can complicate these reactions. Herein, we describe the continuous formation, using an activated packed‐bed of metallic zinc, and subsequent use of organozinc halides. We demonstrate that a single column of zinc can provide excellent yields of organozinc halides and that they can be used downstream in subsequent Negishi cross‐couplings. The preparation of the zinc column and the scope of the reaction are discussed.

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One‐Pot Sandmeyer Trifluoromethylation and Trifluoromethylthiolation
Authors: Bayarmagnai Bilguun , Matheis Christian , Risto Eugen , Goossen Lukas J.
Published: June 2014

Practical one‐pot procedures were developed for both Sandmeyer‐type trifluoromethylations and trifluoromethylthiolations. Starting from broadly available (hetero)aromatic amines, various benzotrifluorides were synthesized in high yields via in situ diazotization and copper‐mediated trifluoromethylation using the inexpensive Ruppert–Prakash trifluoromethylating reagent. In the presence of sodium thiocyanate as a sulfur source, aryl trifluoromethyl thioethers are exclusively formed.

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Methionine and Buthionine Sulfoximines: Syntheses under Mild and Safe Imidation/Oxidation Conditions
Authors: Buglioni Laura , Bizet Vincent , Bolm Carsten
Published: June 2014

Methionine and buthionine sulfoximines (MSO and BSO) are non‐natural amino acids known to inhibit the biosynthesis of glutathione (GSH). The current syntheses of these biologically active molecules involve harsh reaction conditions and the use of hazardous reagents for the sulfur imidation. Here, improved syntheses of MSO and BSO are presented including safe and mild one‐pot imidation/oxidation sequences and single‐step deprotections of three different functionalities.

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Temperature‐Sensitive Composite Films: Synthesis and Characterization of Poly(vinyl acetate)/Polystyrene/ Polypyrrole Ternary Composites
Authors: Eşsİz Serpİl , Sari Bekİr
Published: June 2014

In this study, polypyrrole (PPy) and poly(vinyl acetate)/polystyrene/polypyrrole (PVAc/PS/PPy) ternary composites were synthesized by chemical polymerization using FeCl3 as an oxidant agent. Temperature‐sensitive folding films of PVAc/PS/PPy ternary composites were prepared by casting on glass Petri dishes. The formation of polymer and ternary composites was supported by Fourier transform infrared spectroscopy, and electronic transitions of polymers were determined by ultraviolet–visible spectroscopy. The conductivities of polymers were measured by a four‐probe technique and were found in the range of 10−3 to 10−4 S cm−1. Morphological studies show that all composite films have a smooth surface. The root‐mean‐square (rms) roughness of all films is found to be in the range of 0.145–0.212 nm. The results of thermal gravimetric analysis show that incorporation of PPy in composites improves the thermal stability. X‐ray diffraction analysis demonstrated the amorphous nature of PPy and its ternary composites.
Overcoming Efficiency Limitations of SnS‐Based Solar Cells
Authors: Sinsermsuksakul Prasert , Sun Leizhi , Lee Sang Woon , Park Helen Hejin , Kim Sang Bok , Yang Chuanxi , Gordon Roy G.
Published: June 2014

Thin‐film solar cells are made by vapor deposition of Earth‐abundant materials: tin, zinc, oxygen and sulfur. These solar cells had previously achieved an efficiency of about 2%, less than 1/10 of their theoretical potential. Loss mechanisms are systematically investigated and mitigated in solar cells based on p‐type tin monosulfide, SnS, absorber layers combined with n‐type zinc oxysulfide, Zn(O,S) layers that selectively transmit electrons, but block holes. Recombination at grain boundaries is reduced by annealing the SnS films in H2S to form larger grains with fewer grain boundaries. Recombination near the p‐SnS/n‐Zn(O,S) junction is reduced by inserting a few monolayers of SnO2 between these layers. Recombination at the junction is also reduced by adjusting the conduction band offset by tuning the composition of the Zn(O,S), and by reducing its free electron concentration with nitrogen doping. The resulting cells have an efficiency over 4.4%, which is more than twice as large as the highest efficiency obtained previously by solar cells using SnS absorber layers.
Atherosclerosis in mummified human remains from Vilnius, Lithuania (18th–19th centuries AD): A computed tomographic investigation
Authors: Piombino‐Mascali Dario , Jankauskas Rimantas , Tamošiūnas Algirdas , Valančius Ramūnas , Thompson Randall C. , Panzer Stephanie
Published: June 2014

Objective

Through the study of preserved human remains, it is now known that atherosclerosis, commonly thought to be a modern disease, also existed in historic and prehistoric periods. To date, however, little evidence of atherosclerosis has been reported in samples of tissues from spontaneously mummified bodies that are often found in European crypts and churches.

Methods

Within the framework of the Lithuanian Mummy Project, whole‐body computed tomographic scans of seven spontaneous mummies from a crypt in Vilnius were obtained and assessed for indications of atherosclerosis.

Results

Three of the mummies investigated showed clear evidence of atherosclerosis, which was at times quite severe. Atherosclerosis is believed to have been prevalent among affluent members of Lithuanian society, which is corroborated by historical sources.

Conclusions

In accordance with recent, significant data, this study further demonstrates the antiquity of this disease. Documentary and ethnographic data suggest that lifestyle may have played a role in the onset of atherosclerosis in these individuals. Am. J. Hum. Biol. 26:676–681, 2014. © 2014 Wiley Periodicals, Inc.
The economic burden of disease by industry: Differences in quality‐adjusted life years and associated costs
Authors: Tolbert Davina V. , McCollister Kathryn E. , LeBlanc William G. , Lee David J. , Fleming Lora E. , Muennig Peter
Published: June 2014

Background

This study compares differences in quality‐adjusted life expectancy across the eight original National Occupational Research Agenda (NORA) industry sectors.

Methods

Data from the 1997 to 2012 National Health Interview Survey (NHIS) were used to estimate quality‐adjusted life years (QALYs) for all workers and by NORA sector. Differences in QALYs were calculated and translated into economic values using estimates of the societal willingness‐to‐pay per QALY.

Results

Mean QALYs across workers was 29.17 years. Among NORA sectors, wholesale, and retail trade workers had the highest average QALYs remaining (35.88), while mining workers had the lowest QALYs (31.4). The economic value of this difference ranges from $604,843 to $1,155,287 per worker depending on the societal willingness‐to‐pay per QALY.

Conclusion

The value of life lost within some industries is very high relative to others. Additional investments in occupational safety, benefits, and health promotion initiatives may reduce these losses, but experimental research is needed to assess the effectiveness of such programs. Am. J. Ind. Med. 57:757–763, 2014. © 2014 Wiley Periodicals, Inc.
Heat‐related illness in Washington State agriculture and forestry sectors
Authors: Spector June T. , Krenz Jennifer , Rauser Edmund , Bonauto David K.
Published: June 2014

Background

We sought to describe heat‐related illness (HRI) in agriculture and forestry workers in Washington State.

Methods

Demographic and clinical Washington State Fund workers' compensation agriculture and forestry HRI claims data (1995–2009) and Washington Agriculture Heat Rule citations (2009–2012) were accessed and described. Maximum daily temperature (Tmax) and Heat Index (HImax) were estimated by claim date and location using AgWeatherNet's weather station network.

Results

There were 84 Washington State Fund agriculture and forestry HRI claims and 60 Heat Rule citations during the study period. HRI claims and citations were most common in crop production and support subsectors. The mean Tmax (HImax) was 95°F (99°F) for outdoor HRI claims. Potential HRI risk factors and HRI‐related injuries were documented for some claims.

Conclusions

Agriculture and forestry HRI cases are characterized by potential work‐related, environmental, and personal risk factors. Further work is needed to elucidate the relationship between heat exposure and occupational injuries. Am. J. Ind. Med. 57:881–895, 2014. © 2014 Wiley Periodicals, Inc.