bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate Variability and Change, Impacts and Adaptation Strategies in Dutsin-Ma Local Government Area of Katsina State, Nigeria
Authors: I. B. Abaje, , B. A. Sawa, , O. F. Ati,
Published: May 2014

This paper aimed at examining local peoples’ perceptions on climate variability and change and strategies adopted in combating the impacts of the changes in Dutsin-Ma Local Government Area of Katsina State. A total of 242 questionnaires were administered to households’ heads in the eleven wards of the Local Government Area. Descriptive statistics such as frequency distribution, percentage and mean scores were used in data analysis. The result revealed that majority of the local people have a very good knowledge of climate variability and change in terms of higher temperature, higher rainfall intensity and variability, and the occurrence of extreme weather events such as flood and drought. Findings also revealed that community disobeying God, deforestation, bush burning, combustion of fossil fuel and pollution were the major causes of climate variability and change as perceived by the respondents. The most significant impacts of climate variability and change as perceived by the local people were decline in crop yields, decline in forest resources, water shortages and decrease in soil fertility. These impacts have resulted to rural-urban migration in the area. Sustainable adaptation strategies adopted by the local people are water harvesting, the use of fertilizer/animals dung to improve crop yield, irrigation agriculture, planting of crop varieties and drought resistant crops. It is recommended that strategies for combating impacts of climate variability and change should take into account the traditional and religious beliefs of the people; and there is need to educate the local people to appreciate the scientific basis of climate variability and change.
Utilization of Space-Borne Imagery for Lithologic Mapping: A Case Study From Um Had Area, Central Eastern Desert, Egypt
Authors: Qaoud Nedal
Published: May 2014

Remote sensing data are used to discriminate between the different lithologies covering the Um Had area, Central Eastern Desert of Egypt. Image processing techniques applied to the Enhanced Thematic Mapper (ETM+) data are used for mapping and discriminating the different basement lithologies of Um Had area. Principal component analysis (PCA), minimum noise fraction (MNF) transform and band rationing techniques provide efficient data for lithological mapping. The study area is underlain by gneisses, ophiolitic melange assemblage (talc-serpentinite, metagabbro, metabasalt), granitic rocks, Dokhan volcanics, Hammamat sediments and felsites. The resulting gray-scale PC2, PC3 and PC4 images are best to clearly discriminate the Hammamat sediments, amphibolites and talc-serpentinites, respectively. The gray-scale MNF3 and MNF4 images easily discriminate the felsites and talc-serpentinites, respectively. The band ratio 5/7 and 4/5 images are able to delineate the talc-serpentinites and Hammamat sediments, respectively. Information collected from gray-scale and false color composite images led to generation of detailed lithologic map of Um Had area.
Temperature Change and Its Elevation Dependency in the Source Region of the Yangtze River and Yellow River
Authors: E Chongyi , Hu Hongchang , Xie Hong , Sun Yongjuan
Published: May 2014

The study of temperature change and its elevation dependency in the source region of the Yangtze River and Yellow River have been insufficient owing to the lack of adequate observation stations and long-term climatic data. In this study five temperature indices of 32 stations from 1961 to 2007 in and near the source region are used. The 32 stations all have experienced significant warming; the warming amplitudes are higher than the mean warming amplitude of the Qinghai-Tibetan plateau. The warming amplitudes and the numbers of stations showing significant warming trends in mean minimum temperature and extreme minimum temperature are higher than that of the mean maximum temperature and extreme maximum temperature. The elevation dependency of climatic warming and the amount of significant warming stations are not obvious; the influence of human activity and urbanization may be higher. The warming amplitudes of 26 stations above 3000 m tend to be uniform, and there is no significant law at 6 stations below 3000 m. On the contrary, the ratio of stations showing significant warming in minimum temperature above 4000 m is far less than that of the stations below 4000 m.
The Image of Australia: A Case Study on the Mental Maps of Turkish Immigrants in Sydney
Authors: Gökten Cemil , Südas Ilkay
Published: May 2014

In this study, mental representations of Australia were examined through mental maps in case of Turkish immigrants living in Sydney. The survey is based on 53 mental maps of Australia drawn by Turkish immigrants who reside in Sydney. The participants were asked to list the connotations about Australia, draw a sketch map of the continent and finally fill in an outline Australian map. A prominent difference between these two types of mental maps was in the number and in the categories (place names, natural-geographic elements and symbols) of the components that were displayed by the participants. On the other hand, a comparison of our study with similar academic works conducted from a European example shows that connotations on Australia are predominantly referred to the natural characteristics of the continent. This could be related to the physical isolation Australia as a continent and also to the political indifference tendencies of the urbanized part of the society because of a high living standard.
Space and Infrastructure Functionality in Yaounde Markets
Authors: Ndi Humphrey Ngala , Oben Emmanuel Ebai Enow
Published: May 2014

Market infrastructure plays an undeniable role in the spatial configuration of cities and is central to their efficient functioning. This paper examines the implication of the nature of the social and economic infrastructure in the efficient functioning of market spaces in Yaounde. Over 180 traders in 72.2% of main markets in Yaounde were sampled through a stratified random sampling technique and authorities of the City Council and Sub-Divisional Councils, Market Directors, Market Presidents, and fire brigade workers were equally interviewed through a purposive sampling technique. Findings indicate that an increase in the population of traders is putting a strain on the ability of the local council to provide adequate marketing infrastructure. The absence of adequate market infrastructure has implications on health, sanitation, environment as well as the aesthetic value of markets. The non-site marketability of certain markets has resulted in underutilization. This study suggest a long term commitment by the Yaounde City Council authorities to provide adequate and adapted infrastructure in markets, stronger private sector involvement in market development and the introduction of community self-help programmes and the initiative of private ‘traditional’ market establishments so as to ensure efficient market development.
Energetic electrons in dipolarization events: Spatial properties and anisotropy
Authors: Birn J. , Runov A. , Hesse M.
Published: May 2014

Using the electromagnetic fields of an MHD simulation of magnetotail reconnection, flow bursts, and dipolarization, we further investigate the acceleration of electrons to suprathermal energies. Particular emphasis is on spatial properties and anisotropies as functions of energy and time. The simulation results are compared with Time History of Events and Macroscale Interactions during Substorms observations. The test particle approach successfully reproduces several observed injection features and puts them into a context of spatial maps of the injection region(s): a dominance of perpendicular anisotropies farther down the tail and closer to the equatorial plane, an increasing importance of parallel anisotropy closer to Earth and at higher latitudes, a drop in energy fluxes at energies below ∼10keV, coinciding with the plasma density drop, together with increases at higher energy, a triple peak structure of flux increases near 0°, 90°, and 180°, and a tendency of flux increases to extend to higher energy closer to Earth and at lower latitudes. We identified the plasma sheet boundary layers and adjacent lobes as a main source region for both increased and decreased energetic electron fluxes, related to the different effects of adiabatic acceleration at high and low energies. The simulated anisotropies tend to exceed the observed ones, particularly for perpendicular fluxes at high energies. The most plausible reason is that the MHD simulation lacks the effects of anisotropy‐driven microinstabilities and waves, which would reduce anisotropies.
Thermo‐poro‐mechanics of chemically active creeping faults: 2. Transient considerations
Authors: Veveakis E. , Poulet T. , Alevizos S.
Published: May 2014

This work studies the transient behavior of a chemically active, fluid‐saturated fault zone under shear. These fault zones are displaying a plethora of responses spanning from ultrafast instabilities, like thermal pressurization, to extremely slow creep localization events on geological timescales. These instabilities can be described by a single model of a rate‐dependent and thermally dependent fault, prone to fluid release reactions at critical temperatures which was introduced in our companion work. In this study we integrate it in time to provide regimes of stable creep, nonperiodic and periodic seismic slip events due to chemical pressurization, depending on the physical properties of the fault material. It is shown that this chemically induced seismic slip takes place in an extremely localized band, several orders of magnitude narrower than the initial shear zone, which is indeed the signature field observation. Furthermore, in the field and in laboratory experiments the ultralocalized deformation is embedded in a chemical process zone that forms part of the shear zone. The width of this zone is shown here to depend on the net activation energy of the chemical reaction. The larger the difference in forward and backward activation energies, the narrower is the chemical process zone. We apply the novel findings to invert the physical parameters from a 16year GPS observation of the Cascadia episodic tremor and slip events and show that this sequence is the fundamental mode of a serpentinite oscillator defined by slow strain localization accompanying shear heating and chemical dehydration reaction at the critical point, followed by diffusion and backward reaction leading the system back to slow slip.
A modeling study of coastal circulation and landfast ice in the nearshore Beaufort and Chukchi seas using CIOM
Authors: Wang Jia , Mizobata Kohei , Bai Xuezhi , Hu Haoguo , Jin Meibing , Yu Yanling , Ikeda Moto , Johnson Walter , Perie William , Fujisaki Ayumi
Published: May 2014

This study investigates sea ice and ocean circulation using a 3‐D, 3.8 km CIOM (Coupled Ice‐Ocean Model) under daily atmospheric forcing for the period 1990–2008. The CIOM was validated using both in situ observations and satellite measurements. The CIOM successfully reproduces some observed dynamical processes in the region, including the Bering‐inflow‐originated coastal current that splits into three branches: Alaska Coastal Water (ACW), Central Channel branch, and Herald Valley branch. In addition, the Beaufort Slope Current (BSC), the Beaufort Gyre, the East Siberian Current (ESC), mesoscale eddies, and seasonal landfast ice are well simulated. The CIOM also reproduces reasonable interannual variability in sea ice, such as landfast ice, and anomalous open water (less sea ice) during the positive Dipole Anomaly (DA) years, vice versa during the negative DA years. Sensitivity experiments were conducted with regard to the impacts of the Bering Strait inflow (heat transport), onshore wind stress, and sea ice advection on sea ice change, in particular on the landfast ice. It is found that coastal landfast ice is controlled by the following processes: wind forcing, Bering Strait inflow, and sea ice dynamics.
Ten year observations of gravity waves from thunderstorms in western Africa
Authors: Blanc E. , Farges T. , Le Pichon A. , Heinrich P.
Published: May 2014

A new study of gravity waves produced by thunderstorms was performed using continuous recordings at the IS17 (Ivory Coast) infrasound station of the International Monitoring System developed for the verification of the Comprehensive Nuclear Test‐Ban Treaty. A typical case study is presented for a large thunderstorm on 10–11 April 2006 lasting near 14 h. Comparison with cloud temperature measured by the Meteosat 6 satellite shows that wave activity is large when the cloud temperature is low inside convection cells located over the station. Statistics based on 10 year data show that the wave activity is intense throughout the year with peak periods in May and October and less intense activity in January, in good agreement with the local keraunic level. The seasonal variations of the wave azimuth highlight clear trends from northward direction from February to August to southward direction from August to December. Lightning flashes, observed from space, show a similar motion confirming that thunderstorms are the main sources of the gravity wave activity. The gravity wave azimuth follows the seasonal motion of the tropical rain belt partly related to the Intertropical Convergence Zone of the winds. The contribution of other possible sources, such as wind over relief, is weak because surface winds are weak in this region and only oceans are present south of the station. We conclude that the large observed wave activity is mainly produced by convection associated to thunderstorms.
Simultaneous evaluation of ice cloud microphysics and nonsphericity of the cloud optical properties using hydrometeor video sonde and radiometer sonde in situ observations
Authors: Seiki Tatsuya , Satoh Masaki , Tomita Hirofumi , Nakajima Teruyuki
Published: May 2014

This study utilizes hydrometeor sonde and radiometer sonde in situ observations to simultaneously evaluate ice cloud microphysics and radiative fluxes. In addition, the impact of nonsphericity and heterogeneous ice nucleation schemes on radiative fluxes are examined using a double‐moment bulk cloud microphysics scheme on a midlatitude frontal system. The distribution of simulated outgoing longwave radiation (OLR) is systematically reduced by assuming the presence of columnar ice crystals instead of planar ice crystals because of the difference in the effective radii (the projected area) between the two shapes. However, the choice of the heterogeneous ice nucleation schemes drastically changes the distribution of OLR by modifying the number concentration of the cloud ice (Ni) (more than tenfold). The observed shortwave fluxes are useful for evaluating the simulated number concentration of cloud ice when nonspherical single scattering properties are used instead of spherical single scattering properties. The dependence of the asymmetry factor on the effective radius is the key to quantitatively estimating the ice cloud radiative forcing and determining the aerosol indirect effect on ice clouds. Based on the comparison of shortwave fluxes, the cloud microphysics scheme was found to underestimate the Ni near the cloud base (a robust bias). A possible method of modifying the bias is discussed.
Rapidly changing seasonal sea levels increase flood risk
Authors: Wendel JoAnna
Published: May 2014

Coastal sea levels typically rise in the summer and recede in the winter. Variability in the seasonal sea level cycle can be due to any number of meteorological or oceanographic influences and can affect marine and estuarial habitats.
Climate‐driven changes in chemical weathering and associated phosphorus release since 1850: Implications for the land carbon balance
Authors: Goll Daniel S. , Moosdorf Nils , Hartmann Jens , Brovkin Victor
Published: May 2014

Chemical weathering and associated nutrient release act as a control on atmospheric carbon dioxide (CO2) concentration. To globally quantify the contribution of chemical weathering and associated phosphorus (P) release on the historical trend in terrestrial carbon uptake, we applied a weathering model under climate reconstructions from four Earth System Models. In these simulations, CO2 consumption and P release increased from 1850 to 2005 by 11 ± 3% and 12 ± 4%, respectively. Thereby the intensification of weathering due to climate change could have contributed to a small extent to the trend in terrestrial carbon uptake since the pre–Industrial Period. Using a back of the envelope calculation, we found a feedback strength of CO2 consumption and P release of −0.02 ± 0.01Wm−2K−1 and −0.02 ± 0.01Wm−2K−1, respectively. Although being one magnitude smaller than the carbon cycle feedback, the weathering feedbacks are comparable in strength to small second‐order feedbacks such as methane, fire, or ozone.
Symmetry, randomness, and process in the structure of branched channel networks
Authors: Shelef Eitan , Hilley George E.
Published: May 2014

The branched structure of channel networks has a primary impact on the spatial distribution of elevation, water, and life across Earth's surface from the hillslope to the continental scale and is also observed on other planets. However, the link between this dendritic multiscale structure and the erosional processes that sculpt it has remained elusive for more than six decades. In fact, many topologic measures fail to distinguish natural networks from those generated by random walks. Here we show that a fundamental multiscale topologic symmetry is ingrained into the structure of these networks and reflects the equal elevation drop spanned by flows that split at the drainage divide and meet again downslope. We demonstrate that this symmetry distinguishes random‐walk networks from natural ones, captures the temporal evolution of these networks, and divulges information about the processes that shape them.
Tropical influence independent of ENSO on the austral summer Southern Annular Mode
Authors: Ding Hui , Greatbatch Richard J. , Gollan Gereon
Published: May 2014

A link between atmospheric variability in the tropics independent of ENSO and the Southern Annular Mode (SAM) is found based on seasonal mean data for austral summer. Variations associated with El Niño Southern Oscillation (ENSO) are removed using a linear method, and a Tropics Index (TI) is defined as the zonal average of the ENSO‐removed 500 hPa geopotential height between 10°S and 10°N. Since the detrended TI shows no link to sea surface temperature variability in the tropics, it appears to be related to internal atmospheric variability. We find that the TI can explain about 40% variance of the SAM interannual variability and about 75% of the SAM long‐term trend between 1957/1958 and 2001/2002, where here the SAM includes the ENSO signal. Positive/negative values of the TI are associated with the positive/negative SAM. A possible link between the TI and global warming is noted.
Radiated energy estimations from finite‐fault earthquake slip models
Authors: Senatorski Piotr
Published: May 2014

Radiated seismic energy is expressed in terms of slip velocities by using an overdamped dynamics approximation. This formulation is used to estimate the radiated energy from earthquake finite‐fault models. A correction term is found to show that the approximation underestimates the radiated energy as defined by the full dynamics. The accuracy of the overdamped dynamics solution depends on the rupture history. Two dislocational earthquake models illustrate the dependence of the correction term on the rupture speed and slipping area size. The radiated seismic energies estimated from the finite‐fault models and from seismic waves are compared for real‐world earthquakes. The results are consistent in most cases. Discrepancies between two estimates suggest that both the finite‐fault models and energy estimations from teleseismic data should be revised.
Chorus acceleration of radiation belt relativistic electrons during March 2013 geomagnetic storm
Authors: Xiao Fuliang , Yang Chang , He Zhaoguo , Su Zhenpeng , Zhou Qinghua , He Yihua , Kletzing C. A. , Kurth W. S. , Hospodarsky G. B. , Spence H. E. , Reeves G. D. , Funsten H. O. , Blake J. B. , Baker D. N. , Wygant J. R.
Published: May 2014

The recent launching of Van Allen probes provides an unprecedent opportunity to investigate variations of the radiation belt relativistic electrons. During the 17–19 March 2013 storm, the Van Allen probes simultaneously detected strong chorus waves and substantial increases in fluxes of relativistic (2 − 4.5 MeV) electrons around L = 4.5. Chorus waves occurred within the lower band 0.1–0.5fce (the electron equatorial gyrofrequency), with a peak spectral density ∼10−4 nT2/Hz. Correspondingly, relativistic electron fluxes increased by a factor of 102–103 during the recovery phase compared to the main phase levels. By means of a Gaussian fit to the observed chorus spectra, the drift and bounce‐averaged diffusion coefficients are calculated and then used to solve a 2‐D Fokker‐Planck diffusion equation. Numerical simulations demonstrate that the lower‐band chorus waves indeed produce such huge enhancements in relativistic electron fluxes within 15 h, fitting well with the observation.
Plasmonic Internal Photoemission for Accurate Device In Situ Measurement of Metal‐Organic Semiconductor Injection Barriers
Authors: Dhanker Rijul , Chopra Neetu , Giebink Noel C.
Published: May 2014

Current injection in organic semiconductors remains difficult to predict due in large part to the challenge of characterizing the contact energy barrier and interface density of states directly in organic electronic devices. Here, resonant coupling to surface plasmon polariton modes of a metal contact is demonstrated as a means to carry out internal photoemission (IPE) accurately in disordered organic semiconductor devices and enable direct measurement of the contact injection barrier by isolating true IPE from spurious sub‐gap organic photoconductivity. The substantial increase in sensitivity afforded by resonant coupling enables measurement in the low‐field injection regime where deviation from the standard Fowler prediction is explained quantitatively by the existence of a broad distribution of interface states. This technique is broadly applicable to metals and surface treatments commonly used in organic light emitting diodes, thin film transistors, and photovoltaics, and should therefore provide a quantitative basis to understand and model current injection in these devices over their entire operational lifetime.
A Novel Route to Surface‐Enhanced Raman Scattering: Ag Nanoparticles Embedded in the Nanogaps of a Ag Substrate
Authors: Jin Zhi‐Ming , Gu Wei , Shi Xiao‐Bo , Wang Zhao‐Kui , Jiang Zuo‐Quan , Liao Liang‐Sheng
Published: May 2014

An intense surface‐enhanced Raman scattering (SERS) effect is realized by depositing Ag nanoparticles (NPs) into the nanogaps of a Ag substrate. The nanogaps are formed by the thermal annealing of a Ag film on a silicon substrate. This SERS substrate has an enhancement factor (EF) of 2.3 × 106 and a strong signal enhancement that is 20 times higher than that of substrates without the Ag NPs within the nanogaps. Moreover, the reproducibility is improved with the decreased relative standard deviation of mapping data, which falls from 23.9% down to 12.1%. Its performance is as good as commercial substrates. The electromagnetic distribution between the nanoparticles and nanogaps is simulated by the finite‐difference time‐domain method, which suggests that the additional enhancement of the SERS effect can be mainly attributed to the remarkable increase of the local electromagnetic field coupling among the Ag NPs, which is at least 12 times higher than that of conventional samples with bare Ag NPs.
Ester‐Directed Selective Olefination of Acrylates by Rhodium Catalysis
Authors: Feng Ruokun , Yu Wenlong , Wang Kai , Liu Zhanxiang , Zhang Yuhong
Published: May 2014

Ester‐directed olefination of acrylates via rhodium(III)‐catalysis was developed. Various alkenes were reacted with acrylates to give the desired products in high stereoselectivity. Mechanistic investigations revealed that ester‐directed CH bond activation was the key step to this reaction.

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Application of Taguchi Method to Investigate the Drug Release Behavior of Poly(Acrylamide‐co‐Maleic Acid)/Montmorillonite Nanocomposite Hydrogels
Authors: Dadkhah Daniyal , Navarchian Amir H. , Aref Latif , Tavakoli Naser
Published: May 2014

The pH‐sensitive poly(acrylamide‐co‐maleic acid)/montmorillonite (P(AAm‐MA)/MMT) nanocomposite hydrogels were synthesized through in situ polymerization. The chemical structure and morphology of nanocomposites were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscopy. The resulted disks were then loaded by caffeine, a moderately soluble model drug, using soaking method. The swelling and the drug release experiments were carried out in enzyme‐free simulated gastric and intestinal fluids. The release experiments showed that with the addition of MMT, the burst effect is well controlled, and the barrier property of nanocomposite hydrogels is improved. The effects of some compositional parameters including maleic acid to acrylamide (MA/AAm) molar ratio (MAR), weight percent of MMT (MMT%), cross‐linker/AAm molar ratio (CR), and also the influence of pH of medium on the equilibrium swelling ratio (Q) as well as caffeine release behavior of disks were studied by Taguchi method. The results indicated that shifting the pH value from 1.2 to 7.4 leads to a greater Q. The Q value and the release percentage (P%) increased with increasing the MAR in the structure of disks at pH 7.4. The amounts of P% and Q in both external media decreased with increasing both MMT% and CR. Mathematical behavior of release process was well represented by Peppas Power law model (at short times) and a two‐dimensional Fickian mass transfer model (at long times). The caffeine release behavior in both media was corresponded to the non‐Fickian transport mechanism.
Universal Design Principles for Cascade Heterojunction Solar Cells with High Fill Factors and Internal Quantum Efficiencies Approaching 100%
Authors: Barito Adam , Sykes Matthew E. , Huang Bingyuan , Bilby David , Frieberg Bradley , Kim Jinsang , Green Peter F. , Shtein Max
Published: May 2014

Cascade heterojunction (CHJ) organic solar cells have recently emerged as an alternative to conventional bulk heterojunctions and series‐connected tandems due to their significant promise for high internal quantum efficiency (IQE) and broad spectral coverage. However, CHJ devices thus far have also exhibited poor fill factor (FF), resulting in minimal enhancements (or even decreases) in power conversion efficiency (PCE) when compared with single heterojunction (SHJ) cells. In this study, the major variables controlling the CHJ maximum power point and FF are determined using a combinatorial approach. By matching the maximum power point voltage (VMPP) of the constituent parallel‐connected heterojunctions (subjunctions) and minimizing the injection barriers intrinsic to CHJs, high FF and PCE can be achieved. Optimized CHJ devices are demonstrated with >99% IQE in the interlayer and a 46% increase in PCE compared to a SHJ reference (4.1% versus 2.8%). Devices with a transparent exciton dissociation layer (EDL)/interlayer/acceptor structure are employed, such that each CHJ has absorption efficiency identical to its interlayer/acceptor SHJ counterpart. Using these results, a clear map of performance as a function of material parameters is developed, providing straightforward, universal design rules to guide future engineering of molecules and layer architectures for CHJ organic photovoltaic devices.
The formation and breakup of molten oxide jets under periodic excitation
Authors: Wegener Mirco , Muhmood Luckman , Sun Shouyi , Deev Alex V.
Published: May 2014

The experiments on the capillary breakup of slag jets at high temperatures are presented in this article. The impact of external excitations on the disintegration process was investigated in a furnace with optical access filmed at frame rates up to 10,000 fps. A synthetic calcia‐alumina slag was used to form jets at different temperatures (1570–1660°C) and jet velocities (0.6–1.4 ms−1). The impact of external vibration on the breakup was evident: for low jet velocities, the jet length decreased, the droplet size increased, satellite droplet formation was hindered, and a distinct “pumping mechanism” was observed. For jets with higher velocity, the jet length decreased by 30%, the droplet generation frequency increased from 20 to 250 droplets per second, the drop sizes were uniform, and satellite formation was also suppressed. In this case, the ideal case in which the volume of one wave instability forms one droplet was achieved. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3350–3361, 2014
Exercise tolerance, lung function abnormalities, anemia, and cardiothoracic ratio in sickle cell patients
Authors: van Beers Eduard J. , van der Plas Mart N. , Nur Erfan , Bogaard Harm‐Jan , van Steenwijk Reindert P. , Biemond Bart J. , Bresser Paul
Published: May 2014

Many patients with sickle cell disease (SCD) have a reduced exercise capacity and abnormal lung function. Cardiopulmonary exercise testing (CPET) can identify causes of exercise limitation. Forty‐four consecutive SCD patients (27 HbSS, 11 HbSC, and 6 HbS‐beta thalassemia) with a median age (interquartile range) of 26 (21–41) years underwent pulmonary function tests, CPET, chest x‐ray, and echocardiography to further characterize exercise limitation in SCD. Peak oxygen uptake (V′O2‐peak), expressing maximum exercise capacity, was decreased in 83% of the studied patients. V′O2‐peak correlated with hemoglobin levels (R = 0.440, P = 0.005), forced vital capacity (FVC) (R = 0.717, P < 0.0001). Cardiothoracic ratio on chest x‐ray inversely correlated with FVC (R = −0.637, P < 0.001). According to criteria for exercise limitation, the patients were limited in exercise capacity due to anemia (n = 17), cardiovascular dysfunction (n = 2), musculoskeletal function (n = 10), pulmonary ventilatory abnormalities (n = 1), pulmonary vascular exercise limitation (n = 1), and poor effort (n = 3). In the present study we demonstrate that anemia is the most important determinant of reduced exercise tolerance observed in SCD patients without signs of pulmonary hypertension. We found a strong correlation between various parameters of lung volume and cardiothoracic ratio and we hypothesize that cardiomegaly and relative small chest size may be important causes of the impairment in pulmonary function, that is, reduced long volumes and diffusion capacity, in SCD. Taking into account anthropomorphic differences between SCD patients and controls could help to interpret lung function studies in SCD better. Am. J. Hematol. 89:819–824, 2014. © 2014 Wiley Periodicals, Inc.
Use of autologous hematopoietic cell transplantation as initial therapy in multiple myeloma and the impact of socio‐geo‐demographic factors in the era of novel agents
Authors: Al‐Hamadani Mohammed , Hashmi Shahrukh K. , Go Ronald S.
Published: May 2014

Very effective combination chemotherapy using novel agents has become available in multiple myeloma (MM). Its impact on the use of high‐dose chemotherapy and autologous hematopoietic stem cell transplantation (AHCT) as part of initial therapy is unknown. Using the National Cancer Data Base, we studied the rate of upfront AHCT use among 137,409 newly diagnosed MM patients from 1998 to 2010 in the United States and determined whether disparity exists among various sociodemographic as well as geographic subgroups. Overall, 12,378 (9.0%) patients received AHCT as part of initial treatment. The use of upfront AHCT increased steadily from 5.2% in 1998 to 12.1% in 2010 (trend test, P < 0.001), with no sign of plateau. This was seen across all socio‐geo‐demographic subgroups except among patients treated in the Northeast where the rate fell from 8.7% in 1998 to 6.6% in 2010. In multivariable analysis, patients with the following characteristics were the least likely to receive AHCT (odds ratio): year of diagnosis from 1998 to 2003 before the era of novel agents (0.67), older age (0.35), Black race (0.58), Hispanic ethnicity (0.78), low level of education or annual household income (0.55), residence in a metro area (0.66), no or unknown medical insurance (0.30), treatment at a community cancer center (0.16), and treatment facility located in the Northeast region (0.54). Even after the introduction of novel agents, the rate of upfront AHCT in MM continues to increase annually. Significant disparities exist dependent on demographic, social, and geographic factors. Am. J. Hematol. 89:825–830, 2014. © 2014 Wiley Periodicals, Inc.
Locals, resettlers, and pilgrims: A genetic portrait of three pre‐Columbian Andean populations
Authors: Baca Mateusz , Molak Martyna , Sobczyk Maciej , Węgleński Piotr , Stankovic Anna
Published: May 2014

The common practice of resettlement and the development of administrative and ceremonial systems shaped the population landscape of the Andean region under the Inca rule. The area surrounding Coropuna and Solimana volcanoes, in the Arequipa region (Peru), carried a high‐density, multiethnic population. We studied the genetic variation among three pre‐Columbian populations from three functionally diverse archaeological sites excavated in this region. By analyzing the genetic composition of a large ceremonial center (Acchaymarca), an isolated pastoral settlement (Tompullo 2), and an agricultural settlement characterized by architectural features rare in the region (Puca), we investigated the patterns of population movements and the distribution of genetic diversity. We obtained mitochondrial DNA sequences for 25 individuals and autosomal microsatellite profiles for 20 individuals from Acchaymarca and Puca sites. These were compared with previously published genetic data for Tompullo 2 and other pre‐Columbian populations. We found differences among the genetic portraits of the three populations, congruent with the archaeologically described functions and characteristics of the sites. The Acchaymarca population had the highest genetic diversity and possessed the lowest number of unique mtDNA haplotypes. The Tompullo 2 population exhibited the lowest level of genetic diversity. The Puca population was distinct from the other two populations owing to a high frequency of haplogroup A haplotypes, what potentially explains the non‐local character of the burial architecture. Our analyses of microsatellite data suggest that gene flow between sites was mostly mediated by females, which is consistent with ethnohistorical knowledge of the social organization of the pre‐Columbian communities. Am J Phys Anthropol 154:402–412, 2014. © 2014 Wiley Periodicals, Inc.
Neue chemische Strukturen durch Mikrofluidiksysteme
Authors: Rodrigues Tiago , Schneider Petra , Schneider Gisbert
Published: May 2014

Mikrofluidiksysteme werden für viele Anwendungen im Bereich der chemischen Forschung und Entwicklung eingesetzt, einschließlich der Miniaturisierung von (bio)organischen Synthese‐ und (Bio)analysemethoden. Gegenwärtig beobachten wir den stetig wachsenden Einsatz von Mikrofluidikverfahren bei der Erforschung neuer chemischer Substanzen. Diese neuen Techniken haben bereits einen spürbaren Einfluss auf die chemische Biologie und molekulare Medizin. In diesem Kurzaufsatz beschreiben wir den aktuellen Stand der Forschung und stellen die jüngsten Fortschritte für die Anwendung von Mikrochip‐Reaktoren sowie kleinen und mittelgroßen Coil‐Reaktoren in der Synthese bioaktiver Substanzen vor und geben einen Ausblick auf mögliche künftige Anwendungen dieser vielversprechenden Technologie.
Effect of geometry and loading fractions on energy absorbing properties of fiberglass polymer composite under quasi‐static and low‐velocity impact loadings
Authors: Kim Hyung‐Ick , Jang Hong‐Kyu , Lee Stephanie K. , Suhr Jonghwan
Published: May 2014

The focus of this study is to experimentally investigate the mechanical properties of fiberglass reinforced composite with various aspect ratios and loading fractions in the quasi‐static and low‐velocity impact loading conditions. In this study, short fiberglass reinforced polycarbonate composite materials were fabricated via a solution mixing method and characterized for their tensile properties by varying both fiberglass loading fraction and aspect ratio. The tensile properties including tensile toughness of the fiberglass reinforced composites were characterized and compared. It was observed in this study that the toughness of the composite was dramatically improved whereas the tensile strength and Young's modulus were moderately enhanced over the neat polymer, which were measured to be only up to 15% and 70% increase, respectively. The low‐velocity impact behaviors of the fiberglass composites were also investigated and compared to the tensile toughness of the corresponding composites. Besides, the effect of thickness on their low‐velocity impact properties was investigated. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40821.
Effects of an itaconic acid comonomer on the structural evolution and thermal behaviors of polyacrylonitrile used for polyacrylonitrile‐based carbon fibers
Authors: Fu Zhongyu , Gui Yu , Liu Shuang , Wang Zhe , Liu Baijun , Cao Chunlei , Zhang Huixuan
Published: May 2014

The influence of an acid comonomer on the structural evolution and thermal behaviors of a polyacrylonitrile (PAN) terpolymer containing about 4.19 wt % methyl methacrylate and 0.98 wt % itaconic acid (IA) during a heating treatment were studied by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetry (TG) and compared with the PAN homopolymer. From the results of FTIR spectroscopy and DSC, we found that the presence of the IA comonomer promoted cyclization reactions at a faster rate and broadened the exothermic peak; this eased the concentration of heat release. By comparing the results of the TG data, we found that the presence of the IA comonomer promoted dehydrogenation reactions and the formation of a large quantity of better ladder structures. In additional, the better ladder structures that formed were easier to convert from ladder structures into graphitelike structures. The activation energy of random scissions at about 300°C was calculated by the Kissinger method. The results show that the presence of the IA comonomer inhibited the random scission reactions to some extent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40834.
Fundamental influences on quasistatic and cyclic material behavior of short glass fiber reinforced polyamide illustrated on microscopic scale
Authors: Brunbauer Julia , Mösenbacher Andreas , Guster Christoph , Pinter Gerald
Published: May 2014

In this work, the influences of fiber orientation and weld lines on the morphological structures and the mechanical behavior of polyamide 6.6 (PA6.6‐GF35) are investigated. In quasistatic and fatigue tests tensile and 3‐point‐bending loads are applied. Test temperatures vary between RT and 150°C. Two different specimen types are produced by using injection moulding process to create different fiber orientations as well as weld lines. Fiber orientations are determined using computer tomography. Scanning electron microscopy is used to investigate fracture surfaces of tested specimens. Results show that mechanical properties and morphological structures depend highly on fiber orientation and temperature. Transversely oriented fibers in weld lines result in brittle failure mechanisms and decreased mechanical properties. Different stress distributions in the specimens under tensile and flexural loads have influence on the material behavior as well. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40842.
Effect of 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide on liquid oxygen compatibility of bisphenol a epoxy resin
Authors: Wu Zhanjun , Li Jialiang , Chen Yingpu , Wang Zhi , Li Shichao
Published: May 2014

In this study, bisphenol A epoxy resin (DGEBA) was chemically modified by 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), and the molecular structure of the modified epoxy resin was characterized by Fourier transform infrared spectra. The effects of DOPO on liquid oxygen compatibility of DGEBA were calculated using mechanical impact method. The results indicated that epoxy resin (EP‐P1)/4,4‐diaminobisphenol sulfone (DDS) was compatible with liquid oxygen. When compared with EP/DDS, differential scanning calorimetry and thermogravimetry analyses showed that EP‐P1/DDS and EP‐P2/DDS had much higher glass transition temperatures and char yield. X‐ray photoelectron spectroscopic analysis suggested that phosphorus atoms on the surface of EP‐P1/DDS and EP‐P2/DDS could act in the solid phase to restrain the incompatible reaction, which was in accordance with the flame‐retardant mechanism of phosphorus‐containing compounds. The compatibility mechanism of EP‐P1/DDS was further proposed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40848.
Effect of cross‐linked polycarboxylate‐type superplasticizers on the properties in cementitious system
Authors: Liu Hailu , Pang Hao , Ou Juhua , Zhang Lei , Dai Yongqiang , Liao Bing
Published: May 2014

Fluidity and slump loss are main technical indicators for the quality of concrete. They are related to the dispersion of cement and hydration process, and are greatly affected by the structure of superplasticizers (SPs). For the purpose of obtaining SPs with excellent fluidity and slump retention, water‐soluble cross‐linked polycarboxylate ether copolymers (CLPCs) of acrylic acid and alkenyl alcohol type polyoxyethylene ether were synthesized. In order to gain full understanding of the effect of cross‐linked SPs on the properties in cementitious system, properties of the new SPs in cement paste were compared to those of traditional ones without cross‐linking agents. Mortar tests showed that CLPC performed obvious slow‐release function and kept about 10 mm higher than its initial paste flow after 150 min, while PC incurred loss of 15 mm after 150 min. Adsorption of CLPC on cement resulted in zeta potential being roughly the same as that in the case of PC, and enabled more effective slump retention to cement suspensions by rheological property tests. Ettringite peaks disappeared for CLPC on 1‐day curve and reappeared after 35 days, and the intensity of CH peaks for CLPC appeared weaker than Blank and PC after 1 day. The microstructure of CLPC after 1 day showed a very dense structure of smaller and thinner crystallites, which indicated that the early hydration was greatly delayed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40856.
Polyurethane coatings from liquefied wood containing remains of a copper‐, chromium‐, and boron‐based wood preservative
Authors: Hrastnik David , Humar Miha , Kričej Borut , Pavlič Matjaž , Pori Pavel , Cheumani Yona Arnaud M. , Petrič Marko
Published: May 2014

Preparation of polyurethane wood coatings based on copper‐, chromium‐, and boron (CCB) containing liquefied wood was performed, as an alternative way to manage postconsumed preservative‐contaminated wood. Additionally, we examined the possibility of improvement of selected properties of the liquefied wood‐based coatings by an addition of silica nanoparticles. The constituents of the CCB wood preservative do not exhibit an influence on a liquefaction process and on composition of the liquefied mixture. CCB also does not affect curing of the formulations containing liquefied wood and an isocyanate‐type hardener. Furthermore, influence of CCB on adhesion strength of liquefied wood‐based coatings on a wooden substrate, their hardness, and resistance to scratching and to water, acetone, and alcohol, is not exhibited. However, apart from these, from the applicative point of view, positive results, any improvement of the coating properties by the addition of silica nanoparticles is not shown. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40865.
Recent advances in engineering proteins for biocatalysis
Authors: Li Ye , Cirino Patrick C.
Published: May 2014

Protein engineers are increasingly able to rely on structure‐function insights, computational methods, and deeper understanding of natural biosynthesis processes, to streamline the design and applications of enzymes. This review highlights recent successes in applying new or improved protein engineering strategies toward the design of improved enzymes and enzymes with new activities. We focus on three approaches: structure‐guided protein design, computational design, and the use of novel scaffolding and compartmentalization techniques to improve performance of multienzyme systems. Examples described address problems relating to enzyme specificity, stability, and/or activity, or aim to balance sequential reactions and route intermediates by co‐localizing multiple enzymes. Specific applications include improving production of biofuels using enzymes with altered cofactor specificity, production of high‐value chiral compounds by enzymes with tailored substrate specificities, and accelerated cellulose degradation via multi‐enzyme scaffold assemblies. Collectively, these studies demonstrate a growing variety of computational and molecular biology tools. Continued advances on these fronts coupled with better mindfulness of how to apply proteins in unique ways offer exciting prospects for future protein engineering and biocatalysis research. Biotechnol. Bioeng. 2014;111: 1273–1287. © 2014 Wiley Periodicals, Inc.
Evidence‐Based Anatomy
Authors: Yammine Kaissar
Published: May 2014

Anatomy is a descriptive basic medical science that is no longer considered a research‐led discipline. Many publications in clinical anatomy are prevalence studies treating clinically relevant anatomical variations and reporting their frequencies and/or associations with variables such as age, sex, side, laterality, and ancestry. This article discusses the need to make sense of the available literature. A new concept, evidence‐based anatomy (EBA), is proposed to find, appraise, and synthetize the results reported in such publications. It consists in applying evidence‐based principles to the field of epidemiological anatomy research through evidence synthesis using systematic reviews and meta‐analyses to generate weighted pooled results. Pooled frequencies and associations based on large pooled sample size are likely to be more accurate and to reflect true population statistics and associations more closely. A checklist of a typical systematic review in anatomy is suggested and the implications of EBA for practice and future research, along with its scope, are discussed. The EBA approach would have positive implications for the future preservation of anatomy as a keystone basic science, for sound knowledge of anatomical variants, and for the safety of medical practice. Clin. Anat. 27:847–852, 2014. © 2014 Wiley Periodicals, Inc.