bluuebunny/crossref_metadata_2025 huggingface dataset:
Hundreds of myosin 10s are pushed to the tips of filopodia and could cause traffic jams on actin
Authors: Shangguan Julia , Rock Ronald S
Published: September 2024

Improved technology for counting proteins captures myosin-10 dynamics throughout the filopodial lifecycle, defines requirements for initiating filopodia, and reveals a crowded filopodial tip where motors frequently exceed available actin.Myosin 10 (Myo10) is a motor protein known for its role in filopodia formation. Although Myo10-driven filopodial dynamics have been characterized, there is no information about the absolute number of Myo10 molecules during the filopodial lifecycle. To better understand molecular stoichiometries and packing restraints in filopodia, we measured Myo10 abundance in these structures. We combined SDS-PAGE densitometry with epifluorescence microscopy to quantitate HaloTag-labeled Myo10 in U2OS cells. About 6% of total intracellular Myo10 localizes to filopodia, where it enriches at opposite cellular ends. Hundreds of Myo10s are in a typical filopodium, and their distribution across filopodia is log-normal. Some filopodial tips even contain more Myo10 than accessible binding sites on the actin filament bundle. Live-cell movies reveal a dense cluster of over a hundred Myo10 molecules that initiates filopodial elongation. Hundreds of Myo10 molecules continue to accumulate during filopodial growth, but accumulation ceases when retraction begins. Rates of filopodial elongation, second-phase elongation, and retraction are inversely related to Myo10 quantities. Our estimates of Myo10 molecules in filopodia provide insight into the physics of packing Myo10, its cargo, and other filopodia-associated proteins in narrow membrane compartments. Our protocol provides a framework for future work analyzing Myo10 abundance and distribution upon perturbation.
DNL343 is an investigational CNS penetrant eukaryotic initiation factor 2B activator that prevents and reverses the effects of neurodegeneration caused by the integrated stress response
Authors: Yulyaningsih Ernie , Suh Jung H , Fanok Melania , Chau Roni , Solanoy Hilda , Takahashi Ryan , Bakardjiev Anna I , Becerra Isabel , Benitez N Butch , Chiu Chi-Lu , Davis Sonnet S , Dowdle William E , Earr Timothy , Estrada Anthony A , Gill Audrey , Ha Connie , Haddick Patrick CG , Henne Kirk R , Larhammar Martin , Leung Amy W-S , Maciuca Romeo , Memarzadeh Bahram , Nguyen Hoang N , Nugent Alicia A , Osipov Maksim , Ran Yingqing , Rebadulla Kevin , Roche Elysia , Sandmann Thomas , Wang Jing , Lewcock Joseph W , Scearce-Levie Kimberly , Kane Lesley A , Sanchez Pascal E
Published: September 2024

The integrated stress response (ISR) is a conserved pathway in eukaryotic cells that is activated in response to multiple sources of cellular stress. Although acute activation of this pathway restores cellular homeostasis, intense or prolonged ISR activation perturbs cell function and may contribute to neurodegeneration. DNL343 is an investigational CNS-penetrant small-molecule ISR inhibitor designed to activate the eukaryotic initiation factor 2B (eIF2B) and suppress aberrant ISR activation. DNL343 reduced CNS ISR activity and neurodegeneration in a dose-dependent manner in two established in vivo models – the optic nerve crush injury and an eIF2B loss of function (LOF) mutant – demonstrating neuroprotection in both and preventing motor dysfunction in the LOF mutant mouse. Treatment with DNL343 at a late stage of disease in the LOF model reversed elevation in plasma biomarkers of neuroinflammation and neurodegeneration and prevented premature mortality. Several proteins and metabolites that are dysregulated in the LOF mouse brains were normalized by DNL343 treatment, and this response is detectable in human biofluids. Several of these biomarkers show differential levels in CSF and plasma from patients with vanishing white matter disease (VWMD), a neurodegenerative disease that is driven by eIF2B LOF and chronic ISR activation, supporting their potential translational relevance. This study demonstrates that DNL343 is a brain-penetrant ISR inhibitor capable of attenuating neurodegeneration in mouse models and identifies several biomarker candidates that may be used to assess treatment responses in the clinic.
Bidirectional dysregulation of synaptic glutamate signaling after transient metabolic failure
Authors: Passlick Stefan , Ullah Ghanim , Henneberger Christian
Published: September 2024

Ischemia leads to a severe dysregulation of glutamate homeostasis and excitotoxic cell damage in the brain. Shorter episodes of energy depletion, for instance during peri-infarct depolarizations, can also acutely perturb glutamate signaling. It is less clear if such episodes of metabolic failure also have persistent effects on glutamate signaling and how the relevant mechanisms such as glutamate release and uptake are differentially affected. We modeled acute and transient metabolic failure by using a chemical ischemia protocol and analyzed its effect on glutamatergic synaptic transmission and extracellular glutamate signals by electrophysiology and multiphoton imaging, respectively, in the mouse hippocampus. Our experiments uncover a duration-dependent bidirectional dysregulation of glutamate signaling. Whereas short chemical ischemia induces a lasting potentiation of presynaptic glutamate release and synaptic transmission, longer episodes result in a persistent postsynaptic failure of synaptic transmission. We also observed unexpected differences in the vulnerability of the investigated cellular mechanisms. Axonal action potential firing and glutamate uptake were surprisingly resilient compared to postsynaptic cells, which overall were most vulnerable to acute and transient metabolic stress. We conclude that short perturbations of energy supply lead to a lasting potentiation of synaptic glutamate release, which may increase glutamate excitotoxicity well beyond the metabolic incident.
Effect of unproctored versus proctored examinations on student performance and long-term retention of knowledge
Authors: Zhang Niu , Larose James , Franklin Megan
Published: September 2024

Objective

To compare unproctored and proctored online exams among chiropractic students.

Methods

Pre-existing data of 234 students across 4 consecutive endocrinology classes were analyzed for this study. The course was comprised of 3 lectures (50 minutes per lecture) each week. Student performance was evaluated by midterm exam and summative exam (S1). The students from 3 classes were asked to take a voluntary second summative exam (S2) approximately 7 months after the S1. Since this study was partially conducted during the COVID pandemic, some classes took the midterm and the S1 proctored in the classroom while others took them unproctored from a remote location.

Results

The mean midterm exam (p < .001) and S1 scores (p = .01) for the unproctored group (93.6 ± 7.0 and 88.8 ± 8.2) were significantly higher than the proctored group (88.1 ± 8.2 and 83.9 ± 11.2). The mean time taken by students was much greater for the unproctored exams than for the proctored exams (midterm: 40.7 ± 10.2 versus 16.7 ± 7.0, p < .001; S1: 47.0 ± 8.7 versus 21.5 ± 9.0, p < .001). By contrast, the mean unproctored S2 scores were lower than the proctored group (60.2 ± 14.7 versus 88.1 ± 8.2, p < .001). A linear regression test showed that the final exam was a statistically significant predictor of the recall exam (p < .01, R2 = 28.3%).

Conclusion

The findings suggest that student performance is significantly altered by test format.
Warming and weakening trends of the Kuroshio during 1993–2013
Authors: Wang You‐Lin , Wu Chau‐Ron , Chao Shenn‐Yu
Published: August 2016

Global warming seems leveling off somewhat during 1993–2013 despite increasing atmospheric greenhouse gases. What has happened to the Kuroshio Current system concurrently? Available independent data sets from 1993 to 2013 point to a single answer. Here we show a systemwide weakened Kuroshio during the period despite enhanced warming along its path. The Pacific warm pool upstream of the Kuroshio is still becoming warmer during the period. It injects more heat into the Current despite the weakened Kuroshio, which is associated with weakened westerlies and cyclonic trends of basin‐scale wind stress curl. The weakened Kuroshio will modulate heat and mass exchanges between the tropics and extratropics, impacting the energy balance of climate system. It will also significantly influence mass, heat, salinity, and nutrient exchanges between the Pacific and adjacent marginal seas, which in turn impacts the regional weather, fisheries, and environments.
The 2015 Wolf volcano (Galápagos) eruption studied using Sentinel‐1 and ALOS‐2 data
Authors: Xu Wenbin , Jónsson Sigurjón , Ruch Joël , Aoki Yosuke
Published: August 2016

An energetic eruption started on 25 May 2015 from a circumferential fissure at the summit of Wolf volcano on Isabela Island, western Galápagos. Further eruptive activity within the Wolf caldera followed in mid‐June 2015. As no geodetic observations of earlier eruptions at Wolf exist, this eruption provides an opportunity to study the volcano's magmatic plumbing system for the first time. Here we use interferometric synthetic aperture radar (InSAR) data from both the Sentinel‐1A and ALOS‐2 satellites to map and analyze the surface deformation at four time periods during the activity. These data allow us to identify the two eruption phases and reveal strong coeruptive subsidence within the Wolf caldera that is superimposed on a larger volcano‐wide subsidence signal. Modeling of the surface displacements shows that two shallow magma reservoirs located under Wolf at ~1 km and ~5 km below sea level explain the subsidence and that these reservoirs appear to be hydraulically connected. We also suggest that the transition from the circumferential to the intracaldera eruption may have involved ring fault activity.
Scaling relation between earthquake magnitude and the departure time from P wave similar growth
Authors: Noda Shunta , Ellsworth William L.
Published: August 2016

We introduce a new scaling relation between earthquake magnitude (M) and a characteristic of initial P wave displacement. By examining Japanese K‐NET data averaged in bins partitioned by Mw and hypocentral distance, we demonstrate that the P wave displacement briefly displays similar growth at the onset of rupture and that the departure time (Tdp), which is defined as the time of departure from similarity of the absolute displacement after applying a band‐pass filter, correlates with the final M in a range of 4.5 ≤ Mw ≤ 7. The scaling relation between Mw and Tdp implies that useful information on the final M can be derived while the event is still in progress because Tdp occurs before the completion of rupture. We conclude that the scaling relation is important not only for earthquake early warning but also for the source physics of earthquakes.
Short‐range, overpressure‐driven methane migration in coarse‐grained gas hydrate reservoirs
Authors: Nole Michael , Daigle Hugh , Cook Ann E. , Malinverno Alberto
Published: August 2016

Two methane migration mechanisms have been proposed for coarse‐grained gas hydrate reservoirs: short‐range diffusive gas migration and long‐range advective fluid transport from depth. Herein, we demonstrate that short‐range fluid flow due to overpressure in marine sediments is a significant additional methane transport mechanism that allows hydrate to precipitate in large quantities in thick, coarse‐grained hydrate reservoirs. Two‐dimensional simulations demonstrate that this migration mechanism, short‐range advective transport, can supply significant amounts of dissolved gas and is unencumbered by limitations of the other two end‐member mechanisms. Short‐range advective migration can increase the amount of methane delivered to sands as compared to the slow process of diffusion, yet it is not necessarily limited by effective porosity reduction as is typical of updip advection from a deep source.
Radiative forcing from anthropogenic sulfur and organic emissions reaching the stratosphere
Authors: Yu Pengfei , Murphy Daniel M. , Portmann Robert W. , Toon Owen B. , Froyd Karl D. , Rollins Andrew W. , Gao Ru‐Shan , Rosenlof Karen H.
Published: August 2016

Stratospheric aerosols cool the Earth by scattering sunlight. Although sulfuric acid dominates the stratospheric aerosol, this study finds that organic material in the lowermost stratosphere contributes 30–40% of the nonvolcanic stratospheric aerosol optical depth (sAOD). Simulations indicate that nonvolcanic sAOD has increased 77% since 1850. Stratospheric aerosol accounts for 21% of the total direct aerosol radiative forcing (which is negative) and 12% of the total aerosol optical depth (AOD) increase from organics and sulfate. There is a larger stratospheric influence on radiative forcing (i.e., 21%) relative to AOD (i.e., 12%) because an increase of tropospheric black carbon warms the planet while stratospheric aerosols (including black carbon) cool the planet. Radiative forcing from nonvolcanic stratospheric aerosol mass of anthropogenic origin, including organics, has not been widely considered as a significant influence on the climate system.
Ceres: Sulfur deposits and graphitized carbon
Authors: Hendrix Amanda R. , Vilas Faith , Li Jian‐Yang
Published: August 2016

We report new results from observations of the dwarf planet Ceres using the Hubble Space Telescope in the spectral range 1160–5700 Å. Comparisons between Ceres' UV‐visible spectra and laboratory measurements indicate that both sulfur species and graphitized carbon are important on Ceres' surface. We find a latitudinal gradient in UV absorption, with northern latitudes being more UV absorbing than southern latitudes, a trend that can be explained by increasing abundances of sulfur and SO2 toward northern latitudes. The presence of graphitized carbon is consistent with the surface of this airless body being carbonized in response to processes such as charged particle bombardment. The presence of volatile sulfur species is consistent with the idea that Ceres exhibits geothermal activity. Spectral differences with previous UV observations are likely due to the changing sulfurous and carbonaceous surface of Ceres.
On a flawed conclusion that the 1255 A.D. earthquake ruptured 800 km of the Himalayan Frontal Thrust east of Kathmandu
Authors: Pierce Ian , Wesnousky Steven G.
Published: August 2016

A reexamination of the observations and analysis recently reported to conclude that an 800 km section of the Himalayan Frontal Thrust ruptured in 1255 A.D. shows that the conclusion is flawed and without merit because of misinterpretations of trench logs and incorrect interpretation of radiocarbon statistics.
The suppression of surfzone cross‐shore mixing by alongshore currents
Authors: Spydell Matthew S.
Published: August 2016

Mixing by horizontal surfzone eddies is important to the cross‐shore exchange of material through the surfzone. Surfzone cross‐shore mixing for normally and obliquely incident waves, with very similar incident significant wave heights and directional spreads, is quantified using Boussinesq modeled drifter trajectories. For t < 100 s, surfzone cross‐shore diffusivities K(t) are independent of incident wave angle
owing to similar eddy velocities
 m s−1. For 600 < t < 10,000 s, K(t) is maximum for normally incident waves and decreases with incident wave angle. Thus, the mixing parameterization
is not completely applicable to the surfzone, because
and LE do not change for these experiments. Reduced mixing for obliquely incident waves results from large eddies (wavelengths >200 m) propagating at a velocity C different than the mean current velocity V(x)—the same mechanism that reduces mixing for mesoscale eddies.
Kinematic rupture scenarios and synthetic displacement data: An example application to the Cascadia subduction zone
Authors: Melgar Diego , LeVeque Randall J. , Dreger Douglas S. , Allen Richard M.
Published: August 2016

Scenario ruptures and ground motion simulation are important tools for studies of expected earthquake and tsunami hazards during future events. This is particularly important for large (Mw8+) and very large (Mw8.5+) events for which observations are still limited. In particular, synthetic waveforms are important to test the response of earthquake and tsunami warning systems to large events. These systems are not often exercised in this manner. We will show an application of the Karhunen‐Loève (K‐L) expansion to generate stochastic slip distributions of large events with an example application to the Cascadia subduction zone. We will discuss how to extend the static slip distributions obtained from the K‐L expansion to produce kinematic rupture models and generate synthetic long‐period displacement data at the sampling rates of traditional Global Navigation Satellite Systems (GNSS) stations. We will validate the waveforms produced by this method by comparison to a displacement‐based ground motion prediction equation obtained from GNSS measurements of large earthquakes worldwide.
Variability of oceanic deep convective system vertical structures observed by CloudSat in Indo‐Pacific regions associated with the Madden‐Julian oscillation
Authors: Yuan Jian
Published: August 2016

Vertical structures of deep convective systems during the Madden‐Julian oscillation (MJO) are investigated using CloudSat radar measurements in Indo‐Pacific oceanic areas. In active phases of the MJO, relatively more large systems and connected mesoscale convective systems (CMCSs) occur. The occurrence frequency of CMCSs peaks in the onset phase, a phase earlier than separated mesoscale convective systems (SMCSs). Compared with SMCSs, CMCSs of all sizes have weaker reflectivity above 8 km in their deep precipitating portions and thick anvil clouds closely linked to them, suggesting more “stratiform” physics associated with them. SMCSs and CMCSs together produce relatively the least anvil clouds in the onset phase, while their deep precipitating portions show stronger/weaker reflectivity above 8 km before/after the onset phase. Thus, after the onset phase of the MJO, mesoscale convective systems shift toward a more “convective” organization because SMCSs maximize after the onset, while their internal structures appear more stratiform because internally they have weaker reflectivity above 8 km. CMCSs coincide with a more humid middle troposphere spatially, even at the same locations a few days before they occur. Middle‐tropospheric moistening peaks in the onset phase. Moistening of the free troposphere around deep convective systems shows relatively stronger moistening/drying below 700 hPa before/after the onset phase than domain‐mean averages. Low‐topped clouds occur most frequently around CMCSs and in active phases, consistent with the presence of a moister free troposphere. Coexistence of these phenomena suggests that the role of middle troposphere moisture in the formation of CMCSs should be better understood.
Analysis of land surface parameters and turbulence characteristics over the Tibetan Plateau and surrounding region
Authors: Wang Yinjun , Xu Xiangde , Liu Huizhi , Li Yueqing , Li Yaohui , Hu Zeyong , Gao Xiaoqing , Ma Yaoming , Sun Jihua , Lenschow Donald H. , Zhong Shiyuan , Zhou Mingyu , Bian Xindi , Zhao Ping
Published: August 2016

Based on the results from 11 flux sites during the third Tibetan Plateau (TP) Experiment (TIPEX III), land surface parameters and the turbulence characteristics of the atmospheric surface layer over the TP and surrounding region are analyzed. Monin‐Obukhov similarity theory has been used to calculate the aerodynamic roughness length z0m and the excess resistance to heat transfer kB− 1 = ln(z0m/z0h), and the factors that cause variations of z0m and kB− 1 are investigated. The main drivers for the diurnal variations of surface albedo (α) at different sites are solar elevation, solar radiation, and soil moisture. The eddy correlation method is utilized to inversely calculate bulk transfer coefficients for momentum (CD) and heat (CH) at different sites. The relationships between CD and CH and the wind speed at 10 m follow a power law for unstable stratification. For stable stratification, both CD and CH increase with increasing wind speed when wind speed is less than 5 m/s. Diurnal variations of turbulent fluxes are compared at different sites, and the relationships between turbulent fluxes and other variables are analyzed. Wind speed variance normalized by the friction velocity (σu/u*, σv/u*, σw/u*) for neutral stratification (Cu1, Cv1, Cw1), and temperature and humidity variance normalized by a temperature and humidity scale (σT/T*, σq/q*) under free convection (z/L < −0.1) (CT, Cq) are fitted with similarity relations. The differences in similarity constants (Cu1, Cv1, Cw1, CT, Cq) at different sites are discussed. For stable stratification, cases are divided into weakly stable conditions and intermittent turbulence, and the critical values for these two states are determined. Shear and buoyancy terms in the turbulence kinetic energy equation for different stratifications are analyzed.
New Drug‐Structure‐Directing Agent Concept: Inherent Pharmacological Activity Combined with Templating Solid and Hollow‐Shell Mesostructured Silica Nanoparticles
Authors: Morales Victoria , Gutiérrez‐Salmerón María , Balabasquer Moisés , Ortiz‐Bustos Josefa , Chocarro‐Calvo Ana , García‐Jiménez Custodia , García‐Muñoz Rafael A.
Published: August 2016

One of the major challenges in medicine is the delivery and control of drug release over time. Current approaches take advantage of mesostructured silica nanoparticles (MSNs) as carriers but suffer several problems including complex synthesis that requires sequential steps for (1) removal of surfactants and (2) functionalization of MSNs to allow upload of the drugs. Here, a novel solution is presented to these restrictions: the design of drug‐structure‐directing agents (DSDAs) with dual inherent pharmacological activity and ability to direct the formation of solid and hollow‐shell MSNs. Pharmacologically active DSDAs obtained by amidation of drugs with fatty acids are allowed to form micelles, around which the inorganic species self‐assembled to form MSNs. Since the DSDAs direct the formation of MSNs, the steps to remove surfactants, functionalization, and drug upload are not required. The MSNs thus prepared provide sustained release of the drug over more than six months, as well as rapid cellular internalization by both physiological and tumoral human colon cells without affecting cell viability. Moreover, the gradual intracellular release of both, the active drug and lipid moiety with potential nutraceutical properties is proved. MSN particles designed with this approach are promising vehicles for controlled and sustained intra‐or extracellular drug‐delivery.
Spatio‐Temporal Control of Dynamic Topographic Patterns on Azopolymers for Cell Culture Applications
Authors: Rianna Carmela , Rossano Lucia , Kollarigowda Ravichandran H. , Formiggini Fabio , Cavalli Silvia , Ventre Maurizio , Netti Paolo A.
Published: August 2016

Cell response to exogenous cues is the result of a complex integration of multiple biochemical/biophysical signals, which might occur simultaneously and might be characterized by specific spatial and temporal patterns. Among these signals, surface topography plays an important role in affecting cell functions and fate. However, the current understanding of the interplay between cells and topography relies on static environment. Here the intrinsic light‐responsive properties of azopolymers and the versatility of laser‐based confocal microscope technique is exploited, aiming to induce spatio‐temporal dynamic topographic changes in situ during cell culture. Diverse patterns can be designed on cell‐populated azopolymer films with high control on time, space, and on‐off signal modification. The technique proposed in this study enables the development of synthetic platforms that finely control cell orientation and migration both in time and space. The results may pave the way to unravel complex processes involved in cell‐topography interactions, thus allowing to define the spatio‐temporal features that most effectively influence cell functions.
Direct Optical Fabrication of Fluorescent, Multilevel 3D Nanostructures for Highly Efficient Chemosensing Platforms
Authors: Park Junyong , Seo Jangwon , Jung Ho Kuk , Hyun Gayea , Park Soo Young , Jeon Seokwoo
Published: August 2016

Development of fast and intuitive detection techniques for explosive vapors is highly desired for security applications. Among those techniques, fluorescence quenching has advantages in terms of portability and maintenance cost compared to electrically driven platforms. One of the challenging issues is the restricted sensitivity (i.e., low initial quenching and quenching saturation) caused by hindered diffusion of gaseous analytes inside a dense, solid film, and resulting limited surface area, where the target molecules are reacting. Here, multilevel 3D porous nanostructures are introduced, which possess strong fluorescence and enhanced sensing abilities, produced by a rapid and scalable lithographic technique. The cyanostilbene fluorophore with low‐absorption around patterning wavelengths (≈355 nm) is newly designed to be incorporated into transparent photopolymer. The emission color and intensity of the composite films under excitation can be precisely controlled by adjusting the concentration of fluorophore based on intermolecular effects. The patterned, monolithic film with low‐volume fraction (<40%) offers efficient diffusion paths inside a film and a large number of reaction sites for detecting gaseous analytes, enabling fast fluorescence quenching at an early stage (≈7.5 times higher than the solid film at 30 s) and fully suppressed fluorescence without quenching saturation, which cannot be achieved by conventional solid films.
Benzophenone vs. Copper/Benzophenone in Light‐Promoted Atom Transfer Radical Additions (ATRAs): Highly Effective Iodoperfluoroalkylation of Alkenes/Alkynes and Mechanistic Studies
Authors: Beniazza Redouane , Atkinson Rachel , Absalon Christelle , Castet Frédéric , Denisov Sergey A. , McClenaghan Nathan D. , Lastécouères Dominique , Vincent Jean‐Marc
Published: August 2016

Iodoperfluooralkylation of terminal alkenes and alkynes is effectively photo‐promoted by benzophenone 2 (BP) or the photoreducible copper(II) complex 1. In particular, BP at 1 mol% in methanol upon 365 nm irradiation with a low‐pressure mercury lamp (type TLC=thin layer chromatography, 6 W) results in a fast reaction with excellent reaction yields. Complex 1 and BP 2 exhibited very similar reactivity, suggesting that the reactions involving 1 are likely to be governed by the benzophenone photoactivation processes, rather than copper(I)/(II) redox processes. Mechanistic investigations using transient absorption spectroscopy revealed that a deactivation pathway of the benzophenone triplet (3BP*) is via its reaction with the methanol solvent. We propose that the generated radicals, in particular .CH2OH, play a key role in the initiation step forming Rf. by reacting with RfI, Rf. then entering a radical chain cycle. 1H NMR studies provided evidence that a substantial amount (∼7% NMR yield) of the hemiacetal CH3OCH2OH is formed, i.e., the possible by‐product of the reaction between .CH2OH and RfI. Finally, DFT calculations indicate that a triplet‐triplet energy transfer (TTET) process from 3BP* to perfluorooctyl iodide (C8F17I) is unlikely or should be rather slow under the reaction conditions, consistent with the transient absorption studies.

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Oxidative Alkoxycarbonylation of Alkynes by Means of Aryl α‐Diimine Palladium(II) Complexes as Catalysts
Authors: Beltrani Michela , Carfagna Carla , Milani Barbara , Mancuso Raffaella , Gabriele Bartolo , Fini Francesco
Published: August 2016

The straightforward in situ synthesized bis(2,6‐diisopropyl)acenaphthenequinonediimine palladium triflate catalyst was generally employed for both the mono‐alkoxycarbonylation of terminal alkynes, and the bis‐alkoxycarbonylation of 1,2‐disubstituted alkynes by using mild reaction conditions [carbon monoxide pressure (PCO)=4 bar, temperature=20 °C]. Utilizing low catalyst loading (down to 0.5 mol%), a variety of propiolic esters were synthesized with good to excellent isolated yields. Most importantly the system was very efficient not only with methanol but also with a range of different alcohols, starting from the less hindered benzyl alcohol to the most hindered ones, such as isopropyl alcohol and tert‐butyl alcohol. In addition, aromatic and aliphatic 1,2‐disubstituted alkynes were converted into maleic acid derivatives, together with an acid‐catalyzed isomerization reaction, showing modest to good selectivity and excellent combined yields. In particular 3‐hexyne showed a satisfactory degree of selectivity for the maleic diesters of methanol and benzyl alcohol, obtaining the corresponding products with good isolated yields.

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Construction of Functionalized Azapolycyclic Architectures via Formal Amide Insertion at a Low Catalyst Loading of Copper Trifluoroacetylacetonate
Authors: Harada Shingo , Kato Ryosuke , Nemoto Tetsuhiro
Published: August 2016

A formal amide insertion reaction for the synthesis of nitrogen‐bridged polycyclic frameworks with diverse functionalities was developed using a sustainable copper catalyst as an advantageous alternative to precious rhodium catalysts. The remarkable feature of this methodology is the amount of catalyst loading (0.05 mol%). The optimized reaction conditions enable access to aromatic ring‐fused 8‐azabicyclo[3.2.1]octane, 9‐azabicyclo[3.3.1]nonane, and 6‐azabicyclo[3.2.2]nonane derivatives in moderate to excellent yields.

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Spin Orbit Coupling Controlled Spin Pumping and Spin Hall Magnetoresistance Effects
Authors: Ma Li , Zhou Heng‐An , Wang Lei , Fan Xiao‐Long , Fan Wei‐Jia , Xue De‐Sheng , Xia Ke , Wang Zhe , Wu Ru‐Qian , Guo Guang‐Yu , Sun Li , Wang Xiao , Cheng Xue‐Mei , Zhou Shi‐Ming
Published: August 2016

Effective spin mixing conductance (ESMC) across the nonmagnetic metal (NM)/ferromagnet interface, spin Hall conductivity (SHC), and spin diffusion length (SDL) in the NM layer govern the functionality and performance of pure spin current devices. It is shown that all three parameters can be tuned significantly via the spin orbit coupling (SOC) strength of the NM layer by virtue of the unique Pd1‐xPtx/Y3Fe5O12 system. Surprisingly, the ESMC is observed to increase significantly with x changing from 0 to 1.0, due to the enhanced local density of states for Pt‐rich alloys. The SHC in PdPt alloys turns out to be dominated by the skew scattering term. In particular, the skew scattering parameter has for the first time been rigorously demonstrated to increase with increasing SOC strength. Meanwhile, the SDL is found to decrease when Pd atoms are replaced by heavier Pt atoms, validating the SOC induced spin flip scattering model in polyvalent PdPt alloys. A thorough grasp of the dependence of these parameters on the SOC strength in the present work can help to develop a better theoretical graph on the physics of SOC and spin orbit torque switching, relevant to next generation spintronic devices.
Novel Fe/MnK‐CNTs nanocomposites as catalysts for direct production of lower olefins from syngas
Authors: Wang Di , Ji Jian , Chen Bingxu , Chen Wenyao , Qian Gang , Duan Xuezhi , Zhou Xinggui , Holmen Anders , Chen De , Walmsley John C.
Published: August 2016

Novel Fe/MnK‐CNTs nanocomposites are developed as catalysts for direct production of lower olefins from syngas, delivering a high iron time yield of 337.2 μmolCO·
·s−1 with 51.3%C selectivity toward C2C4 olefins under the optimal reaction conditions (270°C, 2.0 MPa, 30,000 mL h−1
). These catalysts are optimized by varying calcination temperature from 150 to 400°C. Multiple techniques including transmission electron microscopy, Elemental mapping, X‐ray diffraction, X‐ray photoelectron spectroscopy, H2‐temperature‐programmed reduction, and Raman were employed to reveal the relationship between the catalyst nature and unique catalytic behavior. In particular, the resultant catalyst from the calcination temperature of 220°C exhibits the highest selectivity of C2C4 olefins as well as good stability, which are enabled by the trade‐off among the effects of iron particle sizes, promoters, metal‐support interaction and support surface chemistry. Moreover, influences of reaction temperature, reaction pressure and space velocity are also investigated. © 2016 American Institute of Chemical Engineers AIChE J, 63: 154–161, 2017
Reversal of cigarette smoke extract‐induced sinonasal epithelial cell barrier dysfunction through Nrf2 Activation
Authors: Tharakan Anuj , Halderman Ashleigh A. , Lane Andrew P. , Biswal Shyam , Ramanathan Murugappan
Published: August 2016

Background

Environmental factors such as inhaled pollutants like cigarette smoke may play a significant role in diseases of the upper airway including chronic rhinosinusitis (CRS). Recent studies have shown that cigarette smoke causes impaired airway epithelial cell barrier function likely through environmental oxidative stress related pathways. The purpose of this study is to explore whether enhancing nuclear factor erythroid 2 [NF‐E2]‐related factor 2 [Nrf2], the body's master antioxidant system, can ameliorate cigarette smoke–induced sinonasal epithelial cell (SNEC) barrier dysfunction.

Methods

Human SNECs (HSNECs) were grown from control patients at the air‐liquid interface (ALI). HSNECs were stimulated with cigarette smoke extract (CSE) with and without pharmacologic activation of Nrf2. HSNECs were then stained for the epithelial cell junctional proteins zonula occludens 1 (ZO‐1) and junctional adhesion molecule A (JAM‐A) using confocal microscopy. In addition, transepithelial electrical resistance (TER) was measured in cultures before and after stimulation with CSE.

Results

CSE stimulation caused a global disruption of the epithelial junctional proteins ZO‐1 and JAM‐A along with an associated decrease in TER levels. Enhancing Nrf2 levels prior to stimulation with CSE was associated with increased localization of ZO‐1 and JAM‐A levels at the cell surface and statistically significant increases in TER levels.

Conclusion

This is the first study to demonstrate that cigarette smoke induced SNEC barrier dysfunction is reversible by Nrf2 activation. The Nrf2 antioxidant pathway may represent a potential therapeutic target for cigarette smoke–associated sinonasal inflammation.
Successful repair of intraoperative cerebrospinal fluid leaks improves outcomes in endoscopic skull base surgery
Authors: Shahangian Arash , Soler Zachary M. , Baker Andrew , Wise Sarah K. , Rereddy Shruthi K. , Patel Zara M. , Oyesiku Nelson M. , DelGaudio John M. , Hadjipanayis Constantinos G. , Woodworth Bradford A. , Riley Kristen O. , Lee John , Cusimano Michael D. , Govindaraj Satish , Khan Mohemmed N. , Psaltis Alkis , Wormald Peter J. , Santoreneos Stephen , Sindwani Raj , Trosman Samuel , Stokken Janalee K. , Woodard Troy D. , Recinos Pablo F. , Vandergrift W. Alexander , Boling Caitlin , Schlosser Rodney J.
Published: August 2016

Background

The impact of failed cerebrospinal fluid leak (CSF) leak repair in endoscopic skull base surgery has not been adequately studied.

Methods

In this investigation we reviewed patients who had undergone endoscopic skull base surgery between 2002 and 2014 at 7 international centers. Demographic variables, comorbidities, tumor characteristics, and repair techniques were evaluated to determine association with successful repair of CSF leak. Postoperative complications and length of stay were compared among groups.

Results

Data were collected on 2097 patients who were divided into 3 groups: (1) those with no intraoperative leak (n = 1533); (2) those with successful repair of their intraoperative leak (n = 452); and (3) those with failed repair (n = 112). Compared with successful repair, failed repair was associated with an increased risk of intracranial infection (odds ratio [OR], 5.6; 95% confidence interval [CI], 5.3‐13.15), pneumocephalus (OR, 16; 95% CI, 5.8‐44.4), 30‐day readmission (OR, 8.4; 95% CI, 5.3‐13.5), reoperation (OR, 115.4; 95% CI, 56.3‐236.8), and prolonged hospital stay (14.9 vs 7.0 days, p < 0.01). Outcomes in patients who had successful repairs of intraoperative leaks were similar to those who never had leakage. Intraoperative use of pedicled nasoseptal flaps was associated with successful repair (OR, 0.60; 95% CI, 0.34‐0.92).

Conclusion

Intraoperative CSF leaks are a frequent and expected occurrence during endoscopic skull base surgery. Failed CSF leak repair has a significant impact on patient outcomes, with increased rates of postoperative pneumocephalus, intracranial infections, reoperation, deep vein thrombosis, readmission, and prolonged hospital stay. Recognition and repair of intraoperative CSF leaks reduces postoperative complications. Use of pedicled nasoseptal flaps improves outcomes in reconstructing defects at higher risk for postoperative leak.
A Soluble Dynamic Complex Strategy for the Solution‐Processed Fabrication of Organic Thin‐Film Transistors of a Boron‐Containing Polycyclic Aromatic Hydrocarbon
Authors: Matsuo Kyohei , Saito Shohei , Yamaguchi Shigehiro
Published: August 2016

The solution‐processed fabrication of thin films of organic semiconductors enables the production of cost‐effective, large‐area organic electronic devices under mild conditions. The formation/dissociation of a dynamic B−N coordination bond can be used for the solution‐processed fabrication of semiconducting films of polycyclic aromatic hydrocarbon (PAH) materials. The poor solubility of a boron‐containing PAH in chloroform, toluene, and chlorobenzene was significantly improved by addition of minor amounts (1 wt % of solvent) of pyridine derivatives, as their coordination to the boron atom suppresses the inherent propensity of the PAHs to form π‐stacks. Spin‐coating solutions of the thus formed Lewis acid–base complexes resulted in the formation of amorphous thin films, which could be converted into polycrystalline films of the boron‐containing PAH upon thermal annealing. Organic thin‐film transistors prepared by this solution process displayed typical p‐type characteristics.
Palaeogeographic Reconstruction in the Transition Zone: The Role of Geophysical Forward Modelling in Ground Investigation Surveys
Authors: Bates Charles R. , Bates Martin R.
Published: August 2016

Geophysical survey techniques are commonly used as part of studies to reconstruct past geographies in archaeological and palaeoenvironmental landscape investigations onshore and offshore. However, their use across the intertidal zone for constructing contiguous models is far more challenging. In order to enhance the interpretation of the recovered data forward modelling is used here to demonstrate the effective use of a staged approach to site investigation. Examples of data from electrical and electromagnetic techniques have been modelled and tested with ground truth measurements including trial pits, coring and cone penetrometer testing. This combination of forward modelling and testing has proved to be particularly effective at mapping key geological situations of archaeological interest. The approach is demonstrated by reference to varying subsurface sediment types exemplified by two field examples from the UK coast where typical palaeolandscape features, namely incised channels and deeply buried topographies are encountered. These palaeogeographic features were chosen as they have high potential for association with the evidence of past human activity. Copyright © 2016 John Wiley & Sons, Ltd.
Iodoalkyne‐Based Catalyst‐Mediated Activation of Thioamides through Halogen Bonding
Authors: Matsuzawa Akinobu , Takeuchi Shiho , Sugita Kazuyuki
Published: August 2016

Halogen bonding catalysis has recently gained increasing attention as a powerful tool to activate organic molecules. However, the variety of the catalyst structure has been quite limited so far. Herein, we report the first example of the use of an iodoalkyne as a halogen bond donor catalyst. By using an iodoalkyne bearing a pentafluorophenyl group as a catalyst, thioamides were efficiently activated and reacted with 2‐aminophenol to generate benzoxazoles in good yield. Mechanistic studies, including 13C NMR spectroscopic analysis and several control experiments, provided concrete evidence that this catalytic activation is based on halogen bonding. Thus, the results obtained in this study demonstrate that iodoalkynes can serve as a new scaffold for future development of halogen bonding catalysis.
Minimal Volume Simplex (MVS) Polytopic Model Generation and Manipulation Methodology for TP Model Transformation
Authors: Kuti József , Galambos Péter , Baranyi Péter
Published: August 2016

The vertices of a polytopic LPV/qLPV model determine the feasibility of any linear matrix inequality (LMI) based control design as well as the achievable control performance, since the polytope typically includes not only the actual system dynamics. This paper proposes a powerful method to determine suitable polytopic qLPV Tensor‐Product model forms that allows for fine tuning through constraints on the locations of the vertices. The paper shows that these tuning methods are capable of effectively influencing the closed‐loop control performance results from LMI‐based multi‐objective optimisation. The advantages of the proposed methods are their tractability, low computational complexity, as well as their determinism. The key idea behind the proposed methods is to determine vertices in each decoupled parameter‐dimensions of the TP model in such a way that they form a minimal volume enclosing simplex fulfilling further fine tuning conditions on its shape. This is achieved based on the extension of the Minimal Volume Simplex Analysis (MVSA) method, where the volume of the enclosing simplex polytope is minimized by applying Sequential Quadratic Programming with majorization minimization strategy extended with a set of additional constraints influencing the location of certain vertices according to physically established considerations. Besides the comprehensive presentation of the proposed design methodology an expressive numerical example is provided to demonstrate its effectiveness and usability.
Changes in marine fog in a warmer climate
Authors: Kawai Hideaki , Koshiro Tsuyoshi , Endo Hirokazu , Arakawa Osamu , Hagihara Yuichiro
Published: August 2016

Changes in marine fog in a warmer climate are investigated through simulations using the atmospheric component of a global climate model, with both observed and perturbed sea surface temperature forcing. Global changes in marine fog occurrence in different seasons are compared. We show that the changes in marine fog occurrence correspond well to changes in horizontal temperature advection near the surface in a warmer climate. Therefore, the changes in marine fog can be well explained by large‐scale circulation changes. Regarding changes in the characteristics of marine fog, we show that the in‐cloud liquid water content of marine fog is consistently increased in a warmer climate, for a given horizontal surface temperature advection. It is also confirmed that the contribution of changes in marine fog to cloud feedback is not negligible, but is small.
Time control point strategy coupled with transfer coordination in bus schedule design
Authors: Dou Xueping , Yan Yadan , Guo Xiucheng , Gong Xiaolin
Published: August 2016

A schedule consisting of an appropriate arrival time at each time control point can ensure reliable transport services. This paper develops a novel time control point strategy coupled with transfer coordination for solving a multi‐objective schedule design problem to improve schedule adherence and reduce intermodal transfer disutility. The problem is formulated using a robust mixed‐integer nonlinear programming model. The mixed‐integer nonlinear programming model is equivalently transformed into a robust mixed‐integer linear programming model, which is then approximated by a deterministic mixed‐integer linear programming model through Monte Carlo simulation. Thus, the optimal scheduled arrival time at each time control point can be precisely obtained using cplex. Numerical experiments based on three bus lines and the mass rapid transit system in Singapore are presented, and the results show that the schedule determined using the developed model is able to provide not only reliable bus service but also a smooth transfer experience for passengers. Copyright © 2016 John Wiley & Sons, Ltd.
Permeability of currently available microtiter plate sealing tapes fail to fulfil the requirements for aerobic microbial cultivation
Authors: Sieben Michaela , Giese Heiner , Grosch Jan‐Hendrik , Kauffmann Kira , Büchs Jochen
Published: August 2016

Microtiter plate (MTP) sealing tapes are commonly applied in bioprocess development and high throughput screening in order to maintain sterile conditions and avoid liquid evaporation. However, only a few of the commercially available sealing tapes are adequately characterized to guarantee both minimal evaporation and sufficient oxygen supply for aerobic cultivation. Therefore, 12 commercially available sealing tapes are analyzed concerning their water vapor and oxygen permeability. The water vapor permeability is assessed by gravimetrically quantifying the liquid loss due to evaporation. Thereby, the sealing tapes are revealed significant differences. Highly permeable sealing tapes are resulted in liquid loss of up to 25% of the initial filling volume after 8 h at 37°C and 45% ambient humidity. Additionally, the tremendous impact of evaporative cooling on the liquid temperature is detected discovering deviations of up to 3.8°C from the set temperature. The oxygen permeability is assessed by measuring the oxygen transfer rate (OTR). Three out of the 12 tested sealing tapes are impermeable to oxygen while the remaining sealing tapes are ensured sufficient oxygen supply. As a result, all examined sealing tapes are inadequate with respect to either water or oxygen permeation. Based on these novel experimental results, prospective improvements of MTP sealing tapes are presented using a model approach.
Excluded Volume Effects on the Kinetics of Diffusion‐influenced Reversible Bimolecular Reactions: A + B ⇄ C + B
Authors: Ha Jimin , Kim Minjung , Lee Sangyoub
Published: August 2016

We propose a new approach to treat the kinetics of diffusion‐influenced reversible bimolecular reactions and apply it first to the reactions of the type A + B ⇄ C + B. For this type of reactions with some provisions, Gopich et al. showed that the relaxation kinetics can be described exactly in the same way as the reactant decay in an “equivalent” irreversible A + B → C + B reaction. In this article, we will show that the same relationship can be derived in a very elementary way by using a new approach based on the hierarchical kinetic equations governing the reduced distribution functions of reactant molecules. Because our analysis does not require the assumption that the reactants are interaction‐free point particles, the effect of excluded volumes among the reactants can also be evaluated by utilizing the result derived for an irreversible reaction.
Change of Composition in Metallic Fuel Slug of U–Zr Alloy from High‐Temperature Annealing
Authors: Youn Young‐Sang , Lee Jeongmook , Kim Jong‐Yun , Kim Jong Hwan , Song Hoon
Published: August 2016

The U–Zr alloy is a candidate for fuel to be used as metallic fuel in sodium‐cooled fast reactors (SFRs). Its chemical composition before and after annealing at the operational temperature of SFRs (610°C) was investigated using X‐ray photoelectron spectroscopy, Raman spectroscopy, and X‐ray diffraction. The original alloy surface contained uranium oxides with the U(IV) and U(VI) oxidation states, Zr2O3
, and a low amount of uranium metal. After annealing at 610°C, the alloy was composed of uranium metal, uranium carbide, uranium oxide with the U(V) valence state, zirconium metal, and amorphous carbon. Meanwhile, X‐ray diffraction data indicate that the bulk composition of the alloy remained unchanged.