bluuebunny/crossref_metadata_2025 huggingface dataset:
Toward a semantic web of paleoclimatology
Authors: Emile‐Geay Julien , Eshleman Jason A.
Published: February 2013

The paleoclimate record is information‐rich, yet significant technical barriers currently exist before this record can be used to answer scientific questions. Here we make the case for a universal format to structure paleoclimate data. A simple example demonstrates the scientific utility of such a self‐describing way of organizing coral data and meta‐data. This example is generalized to a universal ontology that may form the backbone of an open‐source, open‐access, and crowd‐sourced paleoclimate database. The format is designed to enable semantic searches, and is expected to accelerate discovery on topical scientific problems like climate extremes, the characteristics of natural climate variability, and climate sensitivity to various forcings.
Complementary slip distributions of the largest earthquakes in the 2012 Brawley swarm, Imperial Valley, California
Authors: Wei Shengji , Helmberger Don , Owen Susan , Graves Robert W. , Hudnut Kenneth W. , Fielding Eric J.
Published: February 2013

We investigate the finite rupture processes of two M > 5 earthquakes in the 2012 Brawley swarm by joint inversion of nearby strong motion and high‐rate GPS data. Waveform inversions up to 3 Hz were made possible by using a small event (Mw3.9) for path calibration of the velocity structure. Our results indicate that the first (Mw5.3) event ruptured a strong, concentrated asperity with offsets of ~20 cm centered at a depth of 5 km. The subsequent Mw5.4 event occurred 1.5 h later with a shallower slip distribution that surrounds and is complementary to that of the earlier event. The second event has a longer rise time and weaker high‐frequency energy release compared to the Mw5.3 event. Both events display strong rupture directivity toward the southwest and lack of very shallow (<2 km) coseismic slip. The hypocenters for these events appear to be near or in the bedrock, but most of the slip is distributed at shallower depths (<6 km) and can explain a large part of the GPS offsets for the swarm. The complementary slip distributions of the two events suggest a triggering relationship between them with no significant creep needed to explain the various data sets.
Dense bottom layers in the Scotia Sea, Southern Ocean: Creation, lifespan, and destruction
Authors: Meredith Michael P. , Brown Peter J. , Naveira Garabato Alberto C. , Jullion Loïc , Venables Hugh J. , Messias Marie‐José
Published: February 2013

The lower limb of the Atlantic overturning circulation is renewed by dense waters from the Southern Ocean, a substantial portion of which flow through the Scotia Sea. We report dense bottom layers here, with gradients in temperature and salinity comparable to those seen near the surface of the Southern Ocean. These are overlain by layers with much weaker stratification, and are caused by episodic overflows of dense waters across the South Scotia Ridge, and topographic trapping within deep trenches. One such layer was found to be at least 3–4 years older than the water immediately above. The estimated vertical diffusivity to which this layer was subject is substantially less than the strong basin‐average deep mixing reported previously. We conjecture that (a) vertical mixing in the Scotia Sea is strongly spatially inhomogeneous, and (b) the flushing of these layers, like their formation, is related to overflow events, and hence also strongly episodic.
A comparison of the suspended and dissolved matter dynamics of two large inter‐tropical rivers draining into the Atlantic Ocean: the Congo and the Orinoco
Authors: Laraque Alain , Castellanos Bartolo , Steiger Johannes , Lòpez José Luis , Pandi Albert , Rodriguez Militza , Rosales Judith , Adèle Georges , Perez Jesus , Lagane Christelle
Published: February 2013

This study compares the total suspended sediment (TSS), total dissolved solids (TDS), and dissolved organic carbon (DOC) dynamics of two major inter‐tropical rivers, the Congo in Central Africa and the Orinoco in South America, focusing on sampling undertaken during the period 2006–2010. Both rivers are characterized by similar mean annual discharges into the Atlantic Ocean, on its eastern and western margins, respectively. For both rivers, the results presented are placed in the context of the available longer‐term hydrological time series (Congo: 1903–2010; Orinoco: 1926–2010). The key features of the recent records of material flux for both rivers were established and compared with other published data from the 20th century. The available discharge time series show that the rivers are characterized by similar maximum monthly discharges (Congo: 75 500 m3 s‐1; Orinoco: 85 500 m3 s‐1) and similar inter‐annual variability (Congo: 1.69; Orinoco: 1.66). However, contrasts in low‐flow regime (minimum low flows: Congo: 23 000 m3 s‐1; Orinoco: 2300 m3 s‐1) and seasonal variability (Congo: 3.3; Orinoco: 37.2), as well as in material fluxes were identified. Specific suspended sediment yields for the Orinoco (89 t km‐2 yr‐1) were very significantly higher than those for the Congo (9.4 t km‐2 yr‐1). These differences are mainly explained by contrasts in the physiographic characteristics of the two river basins, such as their contrasting relief. The differences between the TSS fluxes calculated for the Orinoco in this study and those indicated by published data from the second half of the 20th century can be explained by the impact of the hydroelectric dams built in the foothills of the Andean Cordillera. Changes in the TSS fluxes of the Congo are mainly explained by the impact of climatic change on total runoff. Copyright © 2013 John Wiley & Sons, Ltd.
A sensitive liquid chromatography/tandem mass spectrometry method for the determination of natural and synthetic steroid estrogens in seawater and marine biota, with a focus on proposed Water Framework Directive Environmental Quality Standards
Authors: Ronan Jenny M. , McHugh Brendan
Published: February 2013

RATIONALE

Trace levels of natural and synthetic steroid estrogens estrone (E1), 17β‐estradiol (E2) and 17α‐ethynyl estradiol (EE2) have been demonstrated to exert adverse effects in exposed organisms. E2 and EE2 have been proposed for inclusion in the Water Framework Directive (WFD) list of priority pollutants; however, the detection and accurate quantification of these compounds provide significant challenges, due to the low detection limits required.

METHODS

A sensitive method combining ultrasonication, solid‐phase extraction (SPE) and liquid chromatography/tandem mass spectrometry, with electrospray ionisation in negative mode (LC/ESI‐MS/MS), capable of determining E1, E2 and EE2 at concentrations between 0.07 and 60 ng/L for seawater and between 0.4 and 200 ng/g wet weight in Mytilus spp. is reported. Recoveries at the limit of quantification (LOQ) ranged from 95 to 102% and 88 to 100% for water and tissue, respectively. Salinity (12 to 35‰) and typical marine particulate matter loadings (between 10 and 100 mg/L) were not found to affect analyte recoveries.

RESULTS

The first detection of E1 by LC/MS/MS in Irish marine waters (Dublin Bay, at 0.76 ng/L) is reported. Steroids were not detected in Galway Bay, or in any mussel samples from Dublin, Galway and Clare. The level of E2 detected in the dissolved water phase was below the proposed WFD Environmental Quality Standard (EQS) in other surface waters.

CONCLUSIONS

The proposed method is suitable for the detection of E1, E2 and EE2 at biologically relevant concentrations and, due to the specificity offered, is not subject to potential interferences from endogenous E1 and E2 which often complicate the interpretation of estrogenic biomarker assays. Copyright © 2013 John Wiley & Sons, Ltd.
Signatures of equatorial plasma bubbles in VHF satellite scintillations and equatorial ionograms
Authors: McNamara L. F. , Caton R. G. , Parris R. T. , Pedersen T. R. , Thompson D. C. , Wiens K. C. , Groves K. M.
Published: February 2013

Since their discovery in the 1970s, equatorial plasma bubbles (EPBs) have been invoked to explain the propagation of VHF signals on trans‐equatorial circuits at night, and blamed for highly detrimental scintillation of VHF and GHz trans‐ionospheric communications signals in equatorial regions. Over the last four decades, the properties of EPBs have been deduced by multiple techniques such as incoherent scatter radar, 630 nm airglow, depletions in GPS total electron content observations, VHF and GHz scintillations, and HF observations by ionosondes. The initiation and evolution of EPBs have by now been successfully modeled and a good understanding developed of the underlying physics. However, different communities tend to concentrate on a single observing technique, without regard to whether the different techniques provide a consistent physical picture. In contrast, this paper discusses two very different types of observations made on a night‐by‐night basis during the COPEX campaign of late 2002 in Brazil, namely, VHF scintillations and ionograms, and shows that the two methods of observation can provide a consistent interpretation of the properties of EPBs. For example, an EPB seen as an eastward drifting scintillation event can also be seen as an extra ionogram reflection trace that moves closer to and then away from the ionosonde site. The scintillations are attributed to strong gradients across the walls of an EPB, whereas the extra ionogram traces are attributed to oblique reflection of the ionosonde signals from the walls of the EPB.
Latest Quaternary paleoseismology and slip rates of the Longriba fault zone, eastern Tibet: Implications for fault behavior and strain partitioning
Authors: Ren Junjie , Xu Xiwei , Yeats Robert S. , Zhang Shimin
Published: February 2013

Although much work has been done on active tectonics of eastern Tibet, little is known about the Longriba fault zone and its role in strain partitioning. Whether its two sub‐parallel strands (Longriqu and Maoergai faults) can rupture simultaneously in a large earthquake remains unknown. We conducted trenching combined with the interpretation of satellite imagery, field investigations, topographic surveys, and radiocarbon and Optically Stimulated Luminescence (OSL) dating to reconstruct paleoseismic history, and we used displaced terrace risers to estimate geological slip rates. Our results demonstrate that the Longriba fault zone is predominantly right‐lateral with a small southeast‐verging thrust component. Four surface‐rupturing events occurred on the Longriqu fault at 5080 ± 90, 11,100 ± 380, 13,000 ± 260, and 17,830 ± 530 cal yr B.P. Together with our previous trenches on the Maoergai fault, we found that the last event probably ruptured both the Longriqu and Maoergai faults. Prior to the last event, the two strands of the Longriba fault zone experienced alternating earthquakes. The fault zone has a high potential for an earthquake larger than Mw 7. The slip rate of the Longriba fault zone decreases from ~7.5 mm/yr in latest Pleistocene to ~2.1 mm/yr in the Holocene, probably related to a slowing down of the eastern motion of the Tibetan Plateau. The comparison with slip rates at the Longmen Shan fault zone suggests that the Longriba fault zone has an equally important role in strain partitioning in eastern Tibet. This study is helpful to seismic hazard assessment and an understanding of deformation mechanism in eastern Tibet.
ECG interpretation in Brugada syndrome
Authors: Nishizaki Mitsuhiro , Yamawake Noriyoshi , Sakurada Harumizu , Hiraoka Masayasu
Published: February 2013

Type 1 ST‐segment elevation is diagnostic of Brugada syndrome and its presence may be associated with a high risk of arrhythmic events. However, similar changes on electrocardiogram (ECG) are observed in various normal and abnormal conditions. A type 1 ECG can also be unmasked by administration of sodium channel blockers in equivocal or suspected cases of Brugada syndrome, and this drug challenge test is frequently used in the diagnosis of symptomatic patients showing non‐type 1 ECG patterns. The presence of a transient spontaneous type 1 ECG rather than a drug‐induced type I ECG is an important sign for risk prediction of arrhythmia events, even in asymptomatic patients. In asymptomatic individuals, multiple and repeated ECG recordings rather than drug testing are recommended for detecting the transient appearance of a spontaneous type 1 ECG, which may indicate the future development of arrhythmic events. There is little doubt that ECG interpretation, including diagnostic criteria and differential diagnosis, constitutes the hallmark of Brugada syndrome.
FLUTE: A versatile linac-based THz source
Authors: Nasse M. J. , Schuh M. , Naknaimueang S. , Schwarz M. , Plech A. , Mathis Y.-L. , Rossmanith R. , Wesolowski P. , Huttel E. , Schmelling M. , Müller A.-S.
Published: February 2013

A new compact versatile linear accelerator named FLUTE is currently being designed at the Karlsruhe Institute of Technology. This paper presents the status of this 42 MeV machine. It will be used to generate strong (several 100 MV/m) ultra-short (∼1 ps) THz pulses (up to ∼4–25 THz) for photon science experiments, as well as to conduct a variety of accelerator studies. The latter range from comparing different coherent THz radiation generation schemes to compressing electron bunches and studying the electron beam stability. The bunch charge will cover a wide range (∼100 pC–3 nC). Later we plan to also produce ultra-short x-ray pulses from the electron bunches, which, for example, could then be combined for THz pump–x-ray probe experiments.
High power terahertz radiation source based on electron beam wakefields
Authors: Antipov Sergey , Jing Chunguang , Schoessow Paul , Kanareykin Alexei , Yakimenko Vitaly , Zholents Alexander , Gai Wei
Published: February 2013

A table top device for producing high peak power (tens of megawatts to a gigawatt) T-ray beams is described. An electron beam with a rectangular longitudinal profile is produced out of a photoinjector via stacking of the laser pulses. The beam is also run off-crest of the photoinjector rf to develop an energy chirp. After passing through a dielectric loaded waveguide, the beam's energy becomes modulated by its self-wake. In a chicane beamline following the dielectric energy-bunching section this energy modulation is converted to a density modulation—a bunch train. The density modulated beam can be sent through a power extraction section, like a dielectric loaded accelerating structure, or simply can intercept a foil target, producing THz radiation of various bandwidths and power levels.
Coarse-grained simulations of DNA overstretching
Authors: Romano Flavio , Chakraborty Debayan , Doye Jonathan P. K. , Ouldridge Thomas E. , Louis Ard A.
Published: February 2013

We use a recently developed coarse-grained model to simulate the overstretching of duplex DNA. Overstretching at 23 °C occurs at 74 pN in the model, about 6–7 pN higher than the experimental value at equivalent salt conditions. Furthermore, the model reproduces the temperature dependence of the overstretching force well. The mechanism of overstretching is always force-induced melting by unpeeling from the free ends. That we never see S-DNA (overstretched duplex DNA), even though there is clear experimental evidence for this mode of overstretching under certain conditions, suggests that S-DNA is not simply an unstacked but hydrogen-bonded duplex, but instead probably has a more exotic structure.
Tunneling investigation of the electron scattering effect on the momentum-dependent energy gap distribution in MgB2
Authors: Dai Wenqing , Chen Ke , Xi X. X. , Li Qi
Published: February 2013

We have studied the effect of electron scattering on the momentum-dependent energy gap distributions in MgB2 by measuring planar tunnel junctions made from epitaxial MgB2 thin films on different substrates, of different thicknesses, with different junction interface properties, and different counter-electrode materials. The phonon features in the tunneling spectra indicated that the native oxide barrier is mainly MgO with estimated barrier thickness ranging from 1.1 to 1.5 nm and the average barrier height from 1.7 to 2.6 eV. When tunneling into the ab-plane occurred in very clean films, both the π (∼1.8 meV) and σ (∼7.2 meV) gaps were observed with fine structures in the conductance peaks, indicating a distribution of gap values due to anisotropic electron-phonon interaction. The σ gap was enhanced (∼7.9 meV) in MgB2 thin films on SiC substrates which had Tc values over 40 K due to epitaxial tensile strain. As the MgB2 film thickness decreased from 100 nm to 33 nm, the π gap distribution range was narrowed from ∼1.7 meV to ∼1.4 meV, and the fine peak structures disappeared due to the reduced electron mean free path limited by the film thickness. The fine peak structures were also gradually smeared out when the junction resistance increased. The results show that the electron scattering, either from the MgB2 film or the junction interface or barrier, can smear out the gap distribution structures in the tunneling spectra. Deterioration of the MgB2 film surface was also found to cause an increase in the π gap value, likely due to an enhancement of interband scattering.
Coupling the valley degree of freedom to antiferromagnetic order
Authors: Li Xiao , Cao Ting , Niu Qian , Shi Junren , Feng Ji
Published: February 2013

Conventional electronics are based invariably on the intrinsic degrees of freedom of an electron, namely its charge and spin. The exploration of novel electronic degrees of freedom has important implications in both basic quantum physics and advanced information technology. Valley, as a new electronic degree of freedom, has received considerable attention in recent years. In this paper, we develop the theory of spin and valley physics of an antiferromagnetic honeycomb lattice. We show that by coupling the valley degree of freedom to antiferromagnetic order, there is an emergent electronic degree of freedom characterized by the product of spin and valley indices, which leads to spin–valley-dependent optical selection rule and Berry curvature–induced topological quantum transport. These properties will enable optical polarization in the spin–valley space, and electrical detection/manipulation through the induced spin, valley, and charge fluxes. The domain walls of an antiferromagnetic honeycomb lattice harbors valley-protected edge states that support spin-dependent transport. Finally, we use first-principles calculations to show that the proposed optoelectronic properties may be realized in antiferromagnetic manganese chalcogenophosphates (MnPX
3
, X = S, Se) in monolayer form.
Restless legs syndrome in combined hormonal contraception users
Authors: Kamsheh Lyla , Ambrogi Ilana , Rambally Cherridan , Attarian Hrayr
Published: February 2013

The goal of the study was to estimate the prevalence of restless legs syndrome (RLS) among women of childbearing age taking combined hormonal or combined oral contraception (CHC). A survey that included demographic information, contraceptive use history, the four criteria necessary for RLS diagnosis and an International RLS study group severity scale was distributed to 145 women taking CHC and 169 matched control women not on CHC. A high prevalence of moderate to severe RLS of 20.7% was found. A significant correlation between CHC use and RLS was not found (p = 0.53). RLS severity was not significantly associated with CHC use either (p = 0.2127). Women with RLS were significantly heavier compared with those without RLS (p = 0.0015). RLS severity weakly correlated with body mass index (R = 0.26, p = 0.044). Hormonal contraceptive therapy does not increase the risk of developing RLS symptoms.
A Causal Model for Joint Evaluation of Placebo and Treatment‐Specific Effects in Clinical Trials
Authors: Zhang Zhiwei , Kotz Richard M. , Wang Chenguang , Ruan Shiling , Ho Martin
Published: February 2013

Evaluation of medical treatments is frequently complicated by the presence of substantial placebo effects, especially on relatively subjective endpoints, and the standard solution to this problem is a randomized, double‐blinded, placebo‐controlled clinical trial. However, effective blinding does not guarantee that all patients have the same belief or mentality about which treatment they have received (or treatmentality, for brevity), making it difficult to interpret the usual intent‐to‐treat effect as a causal effect. We discuss the causal relationships among treatment, treatmentality and the clinical outcome of interest, and propose a causal model for joint evaluation of placebo and treatment‐specific effects. The model highlights the importance of measuring and incorporating patient treatmentality and suggests that each treatment group should be considered a separate observational study with a patient's treatmentality playing the role of an uncontrolled exposure. This perspective allows us to adapt existing methods for dealing with confounding to joint estimation of placebo and treatment‐specific effects using measured treatmentality data, commonly known as blinding assessment data. We first apply this approach to the most common type of blinding assessment data, which is categorical, and illustrate the methods using an example from asthma. We then propose that blinding assessment data can be collected as a continuous variable, specifically when a patient's treatmentality is measured as a subjective probability, and describe analytic methods for that case.
EGFR and MYC gene copy number aberrations are more common in squamous cell carcinoma than keratoacanthoma: a FISH study
Authors: Jacobs Melissa S. , Persons Diane L. , Fraga Garth R.
Published: February 2013

Epidermal growth factor receptor (EGFR) and MYC genomic aberrations have been described in cutaneous squamous cell carcinoma (SCC) but have not been widely investigated in keratoacanthoma (KA). EGFR and MYC were evaluated by fluorescence in situ hybridization and immunohistochemistry in 8 verrucae, 19 involuting KA (IKA), 23 classic KA (CKA), 6 atypical KA (AKA) and 19 SCC. Increased EGFR gene copy number was seen in 9 of 23 CKA and 14 of 19 SCC (p = 0.03). Increased MYC gene copy number was observed in 7 of 23 CKA and 17 of 19 SCC (p = 0.0001). MYC gene amplification was more common in SCC than CKA (p = 0.005), while EGFR gene amplification was rare and not significant. MYC protein overexpression was identified in 6 of 23 CKA and 14 of 19 SCC (p = 0.005). There was no statistical difference in EGFR protein overexpression in SCC and CKA (p = 0.06). EGFR and MYC aberrations were rare in IKA. AKA showed EGFR and MYC anomalies at an incidence intermediate between CKA and SCC. EGFR and MYC gene copy number aberrations are more common in SCC than KA. The incidence of aberrations parallels the degree of cytologic atypia in KA.
Perception of the motion trajectory of objects from moving cast shadows in infant Japanese macaques (Macaca fuscata)
Authors: Imura Tomoko , Adachi Ikuma , Hattori Yuko , Tomonaga Masaki
Published: February 2013

The shadows cast by moving objects enable human adults and infants to infer the motion trajectories of objects. Nonhuman animals must also be able to discriminate between objects and their shadows and infer the spatial layout of objects from cast shadows. However, the evolutionary and comparative developmental origins of sensitivity to cast shadows have not been investigated. In this study, we used a familiarity/novelty preferential looking procedure to assess the ability of infant macaques, aged 7–24 weeks, to discriminate between a ‘depth’ display containing a ball and cast shadow moving diagonally and an ‘up’ display containing a ball with a diagonal trajectory and a shadow with a horizontal trajectory. The infant macaques could discriminate the trajectories of the balls based on the moving shadows. These findings suggest that the ability to perceive the motion trajectory of an object from the moving shadow is common to both humans and macaques.
Influence of a Nanoporous Zirconia Implant Surface of on Cell Viability of Human Osteoblasts
Authors: Aboushelib Moustafa N. , Osman Essam , Jansen Ineke , Everts Vincent , Feilzer Albert J.
Published: February 2013

Purpose: The dense nonretentive surface of zirconia implants was modified into a nanoporous surface using selective infiltration etching surface treatment. The aim of this study was to investigate the influence of such a nanoporous modified zirconia surface on the attachment of human osteoblasts.

Materials and Methods: Human osteoblasts were cultured for 21 days on (i) selective infiltration etched zirconia (nanoporous surface), (ii) polished zirconia, (iii) polished titanium, or (iv) airborne particle abraded acid etched (SLA) titanium disks. After the culture period the following parameters were assessed: number of cells, the morphology of the cells, the attachment of the cells, alkaline phosphatase activity, and the level of total protein (α= 0.05).

Results: Statistical analysis revealed a significantly higher cell count on the third (F = 17.4, p < 0.001) and eighth day (F = 163, p < 0.001) for nanoporous zirconia and SLA titanium surfaces compared to polished specimens. The number of cells (nanoporous zirconia 160 ± 20/mm2, SLA titanium 133 ± 15/mm2) and cell size (nanoporous zirconia 50.7 ± 3 μm, SLA titanium 42.5 ± 4 μm) were significantly higher than polished specimens. Nanoporous zirconia specimens demonstrated comparable alkaline phosphatase activity (0.0036 ± 0.0035 ng/μl) and intracellular protein content (72.7 ± 0.9 ng/μl) compared to other tested groups. Scanning electron microscopy revealed that cells attached on the polished surface using finger‐like processes, whereas on the nanoporous surface, finger‐like processes were not observed, as the cell membrane appeared to be in close proximity to the underlying surface.

Conclusion: The findings of this study suggest that a nanoporous zirconia surface favors cell growth and attachment compared to a polished surface. It was proposed that a nanoporous zirconia surface may improve clinical performance of zirconia implants.
Stress‐induced brain histone H3 phosphorylation: contribution of the intensity of stressors and length of exposure
Authors: Rotllant David , Pastor‐Ciurana Jordi , Armario Antonio
Published: February 2013

Expression of c‐fos is used for the characterization of brain areas activated by stressors. Recently, some epigenetic markers associated with enhanced transcription have been identified that may be also useful to detect neuronal populations important for the processing of stressors: phosphorylation of histone H3 in serine 10 or 28 (pH3S10 or pH3S28). Then, we compared in rats the response to stress of c‐fos and these epigenetic changes. More specifically, we studied the influence of the type of stressor (novel environment vs. immobilization, IMO) and the dynamics of the response to IMO. Stress increased pH3S10 positive neurons, with a more restricted pattern than that of c‐fos, both in terms of brain areas activated and number of positive neurons. Changes in pH3S10 showed a maximum at 30 min, then progressively declining in most areas in spite of the persistence of IMO. Moreover, the decline was in general more sensitive than c‐fos to the termination of IMO. The pattern of pH3S28 was even more restricted that of pH3S10, but they showed co‐localization. The present data demonstrate a more selective pattern of stress‐induced histone H3 phosphorylation than c‐fos. The factors determining such a selectivity and its biological meaning remain to be studied.
Analysis of the ferromagnetic contribution to the susceptibility by low field and high field methods in sedimentary rocks of the Southern Pyrenees and Northern Ebro foreland basin (Spain)
Authors: Anchuela Óscar Pueyo , Casas‐Sainz Antonio M. , Pueyo Emilio L. , Juan Andrés Pocoví , Imaz Andrés Gil
Published: February 2013

Magnetic susceptibility in rocks is the sum of the contributions of different magnetic particles (paramagnetic, diamagnetic and ferromagnetic s.l.). These contributions can be measured at variable temperatures or at variable fields (hysteresis loops). Both are time‐consuming techniques that cannot be routinely used in magnetic fabrics analysis. In this study, we propose a simplified method to determine the ferro‐ and paramagnetic contributions to the susceptibility, based on the discrete measurement of susceptibility at two different fields (near 0 and 2.5 T). The results obtained in samples from the Southern Pyrenees and Ebro Basin indicate that the ferromagnetic contribution vary considerably within homogeneous susceptibility values and within the expected range of paramagnetic values. Standard bulk susceptibilities higher than 200 10−6 SI contribute significantly to the ferromagnetic fraction (>50% on average).
Active Heat Transfer Enhancement in Single-Phase Microchannels by Using Synthetic Jets
Authors: Fang Ruixian , Khan Jamil A.
Published: February 2013

The present work experimentally investigates the effect of synthetic jets on the heat transfer performance in a microchannel heat sink. The heat sink consists of five parallel rectangular microchannels measuring 500 μm wide, 500 μm deep, and 26 mm long each. An array of synthetic jets with 100 μm diameter orifices is placed right above the microchannel with a total of eight jet orifices per channel. Microjets are synthesized from the fluid flowing through the microchannel. Periodic disturbances are generated when the synthetic jets interact with the microchannel flow. Heat transfer performance is enhanced as local turbulence is generated and penetrates the thermal boundary layer near heated channel wall. The effects of synthetic jets on microchannels heat transfer performance are studied for several parameters including the channel stream flow rate, the synthetic jets strength and operating frequency. It shows that the synthetic jets have higher heat transfer enhancement for microchannel flow at lower channel flow rates. A maximum of 130% heat transfer enhancement is achieved for some test cases. The pressure dynamics introduced by the synthetic jets are also investigated. The synthetic jets cause a minor increase in the pressure drop.
Numerical Investigation on Lock-In Condition and Convective Heat Transfer From an Elastically Supported Cylinder in a Cross Flow
Authors: Baratchi F. , Saghafian M. , Baratchi B.
Published: February 2013

In this numerical study, flow-induced vibrations of a heated elastically supported cylinder in a laminar flow with Re = 200 and Pr = 0.7 are simulated using the moving overset grids method. This work is carried out for a wide range of natural frequencies of the cylinder, while for all cases mass ratio and reduced damping coefficient, respectively, are set to 1 and 0.01. Here we study lock-in condition and its effects on force coefficients, the amplitude of oscillations, vortex shedding pattern, and Nusselt number and simultaneously investigate the effect of in-line oscillations of the cylinder on these parameters. Results show that for this cylinder, soft lock-in occurs for a range of natural frequencies and parameters like Nusselt number, and the amplitude of oscillation reach their maximum values in this range. In addition, this study shows that in-line oscillations of the cylinder have an important effect on its dynamic and thermal behavior, and one-degree-of-freedom simulation, for an elastic cylinder, which can vibrate freely in a flow field, is only valid for cases far from soft lock-in range.
Maximum Drag Reduction Asymptote for Surfactant-Based Fluids in Circular Coiled Tubing
Authors: Kamel Ahmed H. , Shah Subhash N.
Published: February 2013

Surfactants are superior to polymers in reducing drag and their advantages are very well established. As drag reducers, several factors, such as concentration, temperature, salinity, shear rate, etc., can affect their behavior. Other unique factors relevant to surfactants may include tubing diameter (scale-up effect), head group structure, counterion, charge, etc. Although, drag reduction envelope is customarily employed to investigate drag reduction phenomena, it is defined only for polymeric fluids in both straight and coiled tubing and for surfactant-based (SB) fluids in straight tubing. No such envelope is available for SB fluids in coiled tubing. The present research aims at experimentally investigating the drag reduction characteristics of the most widely used Aromox APA-T surfactant-based fluids. It is a highly active surfactant used as gelling agent in aqueous and brine base fluids. Flow data are gathered using small and large scale flow loops. Straight and coiled tubing with various sizes (1.27 cm to 7.30 cm o.d.) and curvature ratios (0.01 to 0.031) covering the field application range are utilized. The results show that SB fluids exhibit superior drag reduction characteristics. Their behavior is significantly affected by surfactant concentration, shear, tubing size, and geometry. Higher drag reduction is seen in straight tubing than in coiled tubing and increasing curvature ratio yields higher friction pressure losses. In coiled tubing, SB fluids exhibit better drag reduction characteristics than Shah and Zhou maximum drag reduction (MDR) asymptote for polymeric fluids. Therefore, a new maximum drag reduction asymptote is developed using data gathered in 1.27 cm o.d. tubing. The proposed correlation agrees with Zakin MDR asymptote for SB fluids in straight tubing where the curvature ratio is set to be zero. Employing the proposed correlation, a modified drag reduction envelope can be used to evaluate drag reduction characteristics of SB fluids.
Numerical Prediction of Fluid-Elastic Instability in Normal Triangular Tube Bundles With Multiple Flexible Circular Cylinders
Authors: Houri Jafari Hamed , Ghadiri Dehkordi Behzad
Published: February 2013

Prediction of fluid-elastic instability onset is a great matter of importance in designing cross-flow heat exchangers from the perspective of vibration. In the present paper, the threshold of fluid-elastic instability has been numerically predicted by the simulation of incompressible, unsteady, and turbulent cross flow through a tube bundle in a normal triangular arrangement. In the tube bundle under study, there were single or multiple flexible cylinders surrounded by rigid tubes. A finite volume solver based on a Cartesian-staggered grid was implemented. In addition, the ghost-cell method in conjunction with the great-source-term technique was employed in order to directly enforce the no-slip condition on the cylinders' boundaries. Interactions between the fluid and the structures were considered in a fully coupled manner by means of intermittence solution of the flow field and structural equations of motion in each time step of the numerical modeling algorithm. The accuracy of the solver was validated by simulation of the flow over both a rigid and a flexible circular cylinder. The results were in good agreement with the experiments reported in the literatures. Eventually, the flow through seven different flexible tube bundles was simulated. The fluid-elastic instability was predicted and analyzed by presenting the structural responses, trajectory of flexible cylinders, and critical reduced velocities.
Field emission from nanometer-scale tips of crystalline PbZrxTi1−xO3
Authors: Fletcher Patrick C. , Mangalam Vengadesh Kumara R. , Martin Lane W. , King William P.
Published: February 2013

The authors report field emission from nanometer-sharp tips of polarized PbZrxTi1−xO3 (PZT), silicon, and platinum. The PZT nanoemitters are fabricated in a batch fabrication process from single-crystal silicon tips that are coated with a 30 nm thick film of crystalline PZT. The nanoemitters start to emit electrons at fields as low as 2 V/μm and reach threshold emission, or turn-on, at fields as low as 3.9 V/μm. The turn-on field is 3.9 V/μm for PbZr0.2Ti0.8O3, 6.8 V/μm for PbZr0.52Ti0.48O3, and 10.75 V/μm for PbZr0.8Ti0.2O3. The silicon nanoemitters have an electron emission turn-on field of 7.2 V/μm, and the platinum nanoemitters have an electron emission turn-on field of 5.75 V/μm. Using a Fowler-Nordheim analysis, the calculated effective work function of the PbZr0.2Ti0.8O3 film is 1.00 eV, and the field amplification factor is ∼1526.
Characterization of the Achromobactin Iron Acquisition Operon in Sodalis glossinidius
Authors: Smith Caitlin L. , Weiss Brian L. , Aksoy Serap , Runyen-Janecky Laura J.
Published: February 2013

Sodalis glossinidius
is a facultative, extra- and intracellular symbiont found in most tissues of the tsetse fly (
Glossinia
sp.).
Sodalis
has a putative achromobactin siderophore iron acquisition system on the pSG1 plasmid. Reverse transcription (RT)-PCR analysis revealed that the achromobactin operon is transcribed as a single polycistronic molecule and is expressed when
Sodalis
is within the tsetse fly. Expression of the achromobactin operon was repressed under iron-replete conditions; in a mutant that lacks the iron-responsive transcriptional repressor protein Fur, expression was aberrantly derepressed under these iron-replete conditions, indicating that the Fur protein repressed achromobactin gene expression when iron was plentiful. A putative Fur binding site within the
Sodalis
achromobactin promoter bound Fur in
Escherichia coli
Fur titration assays. Wild-type
Sodalis
produced detectable siderophore
in vitro
, but a mutation in the putative achromobactin biosynthesis gene
acsD
eliminated detectable siderophore production in
Sodalis
. Reduced growth of the siderophore synthesis mutant was reconstituted by addition of exogenous achromobactin, suggesting the strain retains a functional siderophore transport system; however, reduced growth of a
Sodalis
ferric-siderophore outer membrane receptor mutant with a mutation in
acr
was not reconstituted by exogenous siderophore due to its defective transporter. The
Sodalis
siderophore synthesis mutant showed reduced growth in tsetse that lacked endogenous symbionts (aposymbiotic) when the flies were inoculated with
Sodalis
intrathoracically, but not when inoculated
per os
. Our findings suggest that
Sodalis
siderophores play a role in iron acquisition in certain tsetse fly tissues and provide evidence for the regulation of iron acquisition mechanisms in insect symbionts.
Campylobacter jejuni Dps Protein Binds DNA in the Presence of Iron or Hydrogen Peroxide
Authors: Huergo Luciano F. , Rahman Hossinur , Ibrahimovic Adis , Day Christopher J. , Korolik Victoria
Published: February 2013

Iron is an essential cofactor for many enzymes; however, this metal can lead to the formation of reactive oxygen species. Ferritin proteins bind and oxidize Fe
2+
to Fe
3+
, storing this metal in a nonreactive form. In some organisms, a particular subfamily of ferritins, namely, Dps proteins, have the ability to bind DNA. Here we show that the
Campylobacter jejuni
Dps has DNA binding activity that is uniquely activated by Fe
2+
or H
2
O
2
at below neutral pH. The Dps-DNA binding activity correlated with the ability of Dps to self-aggregate. The Dps-DNA interaction was inhibited by NaCl and Mg
2+
, suggesting the formation of ionic interactions between Dps and DNA. Alkylation of cysteines affected DNA binding in the presence of H
2
O
2
but not in the presence of Fe
2+
. Replacement of all cysteines in
C. jejuni
Dps with serines did not affect DNA binding, excluding the participation of cysteine in H
2
O
2
sensing. Dps was able to protect DNA
in vitro
from enzymatic cleavage and damage by hydroxyl radicals. A
C. jejuni dps
mutant was less resistant to H
2
O
2
in vivo
. The concerted activation of Dps-DNA binding in response to low pH, H
2
O
2
, and Fe
2+
may protect
C. jejuni
DNA during host colonization.
Sympathetic activation increases NO release from eNOS but neither eNOS nor nNOS play an essential role in exercise hyperemia in the human forearm
Authors: Shabeeh Husain , Seddon Michael , Brett Sally , Melikian Narbeh , Casadei Barbara , Shah Ajay M. , Chowienczyk Phil
Published: February 2013

Nitric oxide (NO) release from endothelial NO synthase (eNOS) and/or neuronal NO synthase (nNOS) could be modulated by sympathetic nerve activity and contribute to increased blood flow after exercise. We examined the effects of brachial-arterial infusion of the nNOS selective inhibitor S-methyl-l-thiocitrulline (SMTC) and the nonselective NOS inhibitor NG-monomethyl-l-arginine (l-NMMA) on forearm arm blood flow at rest, during sympathetic activation by lower body negative pressure, and during lower body negative pressure immediately after handgrip exercise. Reduction in forearm blood flow by lower body negative pressure during infusion of SMTC was not significantly different from that during vehicle (−28.5 ± 4.02 vs. −34.1 ± 2.96%, respectively; P = 0.32; n = 8). However, l-NMMA augmented the reduction in forearm blood flow by lower body negative pressure (−44.2 ± 3.53 vs. −23.4 ± 5.71%; n = 8; P < 0.01). When lower body negative pressure was continued after handgrip exercise, there was no significant effect of either l-NMMA or SMTC on forearm blood flow immediately after low-intensity exercise ( P = 0.91 and P = 0.44 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10) or high-intensity exercise ( P = 0.46 and P = 0.68 for l-NMMA vs. saline and SMTC vs. saline, respectively; each n = 10). These results suggest that sympathetic activation increases NO release from eNOS, attenuating vasoconstriction. Dysfunction of eNOS could augment vasoconstrictor and blood pressure responses to sympathetic activation. However, neither eNOS nor nNOS plays an essential role in postexercise hyperaemia, even in the presence of increased sympathetic activation.
Localized Immunotherapy via Liposome-Anchored Anti-CD137 + IL-2 Prevents Lethal Toxicity and Elicits Local and Systemic Antitumor Immunity
Authors: Kwong Brandon , Gai S. Annie , Elkhader Jamal , Wittrup K. Dane , Irvine Darrell J.
Published: February 2013

Immunostimulatory agonists such as anti-CD137 and interleukin (IL)-2 have elicited potent antitumor immune responses in preclinical studies, but their clinical use is limited by inflammatory toxicities that result upon systemic administration. We hypothesized that by rigorously restricting the biodistribution of immunotherapeutic agents to a locally accessible lesion and draining lymph node(s), effective local and systemic antitumor immunity could be achieved in the absence of systemic toxicity. We anchored anti-CD137 and an engineered IL-2Fc fusion protein to the surfaces of PEGylated liposomes, whose physical size permitted dissemination in the tumor parenchyma and tumor-draining lymph nodes but blocked entry into the systemic circulation following intratumoral injection. In the B16F10 melanoma model, intratumoral liposome-coupled anti-CD137 + IL-2Fc therapy cured a majority of established primary tumors while avoiding the lethal inflammatory toxicities caused by equivalent intratumoral doses of soluble immunotherapy. Immunoliposome therapy induced protective antitumor memory and elicited systemic antitumor immunity that significantly inhibited the growth of simultaneously established distal tumors. Tumor inhibition was CD8+ T-cell–dependent and was associated with increased CD8+ T-cell infiltration in both treated and distal tumors, enhanced activation of tumor antigen–specific T cells in draining lymph nodes, and a reduction in regulatory T cells in treated tumors. These data suggest that local nanoparticle-anchored delivery of immuno-agonists represents a promising strategy to improve the therapeutic window and clinical applicability of highly potent but otherwise intolerable regimens of cancer immunotherapy. Cancer Res; 73(5); 1547–58. ©2012 AACR.
The Unromantic Rousseauian: Scanlon on Justice, Value Coherence and Freedom
Authors: Hussain Waheed
Published: February 2013

Scanlon differs from many liberals – Isaiah Berlin, for example – in that he rejects deep value pluralism. He thinks that the requirements of social justice actually cohere with the requirements of other political values. But like many other liberals, Scanlon does not think that value coherence has any implications for the kind of freedom that we should care about in assessing social and political institutions. In this paper, I take issue with Scanlon’s view of the relation between value coherence and freedom. Following Rousseau, I argue that value coherence does in fact contribute to our freedom, and that we should structure our basic institutions so as to increase value coherence and thereby enhance our freedom overall.
On the Possibility of Corporate Apologies
Authors: Cohen Andrew I. , Samp Jennifer A.
Published: February 2013

This paper argues against an individualist challenge to the possibility of corporate apologies. According to this challenge, corporations always and only act through their members; thus they are not the sorts of entities that can apologize. Consequently there can be no corporate apologies. Against this challenge, this paper argues that even if corporate acts can be analyzed as acts by individuals within certain relationships, there can still be corporate apologies. This paper offers a noneliminative individualist account of such apologies. The paper also responds to various substantive objections to the possibility of such apologies.
The investigation of a traditional Chinese medicine, Guizhi Fuling Wan (GFW) as an intravesical therapeutic agent for urothelial carcinoma of the bladder
Authors: Lu Chi-Chen , Lin Mei-Yi , Chen Syue-Yi , Shen Cheng-Huang , Chen Lih-Geeng , Hsieh Hsiao-Yen , Chan Michael WY , Hsu Cheng-Da
Published: February 2013

Background

The high risk of recurrence faced by patients with bladder cancer has necessitated the administration of supplemental intravesical chemotherapy; however, such treatments often result in severe side effects. As a result, novel intravesical agents with enhanced efficacy and minimal toxicity are urgently required for the treatment of bladder cancer.

Methods

Guizhi Fuling Wan (GFW) is a traditional Chinese medicine shown to inhibit the growth of hepatocellular carcinoma. This study evaluated the growth inhibition of GFW using normal human urothelial cells and bladder cancer cells; the efficacy of GFW treatment was further compared with mitomycin C, epirubicin, and cisplatin. We also examined the progression of cell cycle and apoptosis in bladder cancer cells in response to GFW treatment. CCK-8 was employed to analyze cell viability and flow cytometry was used to study the cell cycle and apoptosis. The mechanisms underlying GFW-induced cell cycle arrest were determined by Western blot analysis.

Results

Our data demonstrate the potent inhibitory effect of GFW in the proliferation of bladder cancer cell lines, BFTC 905 and TSGH 8301. GFW presented relatively high selectivity with regard to cancer cells and minimal toxicity to normal urothelial cells. Our results also demonstrate that GFW interferes with cell cycle progression through the activation of CHK2 and P21 and induces apoptosis in these bladder cancer cells.

Conclusions

Our results provide experimental evidence to support GFW as a strong candidate for intravesicle chemotherapy against bladder cancer.