• A 100,000 Scale Factor Radar Range

      Blanche, Pierre-Alexandre; Neifeld, Mark; Peyghambarian, Nasser; Univ Arizona, Coll Opt Sci (NATURE PUBLISHING GROUP, 2017-12-19)
      The radar cross section of an object is an important electromagnetic property that is often measured in anechoic chambers. However, for very large and complex structures such as ships or sea and land clutters, this common approach is not practical. The use of computer simulations is also not viable since it would take many years of computational time to model and predict the radar characteristics of such large objects. We have now devised a new scaling technique to overcome these difficulties, and make accurate measurements of the radar cross section of large items. In this article we demonstrate that by reducing the scale of the model by a factor 100,000, and using near infrared wavelength, the radar cross section can be determined in a tabletop setup. The accuracy of the method is compared to simulations, and an example of measurement is provided on a 1mm highly detailed model of a ship. The advantages of this scaling approach is its versatility, and the possibility to perform fast, convenient, and inexpensive measurements.
    • The 1997 Mars Pathfinder Spacecraft Landing Site: Spillover Deposits from an Early Mars Inland Sea

      Rodriguez, J A P; Baker, V R; Liu, T; Zarroca, M; Travis, B; Hui, T; Komatsu, G; Berman, D C; Linares, R; Sykes, M V; et al. (NATURE PUBLISHING GROUP, 2019-02-25)
      The Martian outflow channels comprise some of the largest known channels in the Solar System. Remote-sensing investigations indicate that cataclysmic floods likely excavated the channels ~3.4 Ga. Previous studies show that, in the southern circum-Chryse region, their flooding pathways include hundreds of kilometers of channel floors with upward gradients. However, the impact of the reversed channel-floor topography on the cataclysmic floods remains uncertain. Here, we show that these channel floors occur within a vast basin, which separates the downstream reaches of numerous outflow channels from the northern plains. Consequently, floods propagating through these channels must have ponded, producing an inland sea, before reaching the northern plains as enormous spillover discharges. The resulting paleohydrological reconstruction reinterprets the 1997 Pathfinder landing site as part of a marine spillway, which connected the inland sea to a hypothesized northern plains ocean. Our flood simulation shows that the presence of the sea would have permitted the propagation of low-depth floods beyond the areas of reversed channel-floor topography. These results explain the formation at the landing site of possible fluvial features indicative of flow depths at least an order of magnitude lower than those apparent from the analyses of orbital remote-sensing observations.
    • 2D semiconductor nonlinear plasmonic modulators

      Klein, Matthew; Badada, Bekele H; Binder, Rolf; Alfrey, Adam; McKie, Max; Koehler, Michael R; Mandrus, David G; Taniguchi, Takashi; Watanabe, Kenji; LeRoy, Brian J; et al. (NATURE PUBLISHING GROUP, 2019-07-22)
      A plasmonic modulator is a device that controls the amplitude or phase of propagating plasmons. In a pure plasmonic modulator, the presence or absence of a plasmonic pump wave controls the amplitude of a plasmonic probe wave through a channel. This control has to be mediated by an interaction between disparate plasmonic waves, typically requiring the integration of a nonlinear material. In this work, we demonstrate a 2D semiconductor nonlinear plasmonic modulator based on a WSe2 monolayer integrated on top of a lithographically defined metallic waveguide. We utilize the strong interaction between the surface plasmon polaritons (SPPs) and excitons in the WSe2 to give a 73 % change in transmission through the device. We demonstrate control of the propagating SPPs using both optical and SPP pumps, realizing a 2D semiconductor nonlinear plasmonic modulator, with an ultrafast response time of 290 fs.
    • A wind-albedo-wind feedback driven by landscape evolution

      Abell, Jordan T.; Pullen, Alex; Lebo, Zachary J.; Kapp, Paul; Gloege, Lucas; Metcalf, Andrew R.; Nie, Junsheng; Winckler, Gisela; Univ Arizona, Dept Geosci (NATURE PUBLISHING GROUP, 2020-01)
      The accurate characterization of near-surface winds is critical to our understanding of past and modern climate. Dust lofted by these winds has the potential to modify surface and atmospheric conditions as well as ocean biogeochemistry. Stony deserts, low dust emitting regions today, represent expansive areas where variations in surficial geology through time may drastically impact near-surface conditions. Here we use the Weather Research and Forecasting (WRF) model over the western Gobi Desert to demonstrate a previously undocumented process between wind-driven landscape evolution and boundary layer conditions. Our results show that altered surficial thermal properties through winnowing of fine-grained sediments and formation of low-albedo gravel-mantled surfaces leads to an increase in near-surface winds by up to 25%; paradoxically, wind erosion results in faster winds regionally. This wind-albedo-wind feedback also leads to an increase in the frequency of hours spent at higher wind speeds, which has implications for dust emission potential.
    • ABC transporter mis-splicing associated with resistance to Bt toxin Cry2Ab in laboratory- and field-selected pink bollworm

      Mathew, Lolita G.; Ponnuraj, Jeyakumar; Mallappa, Bheemanna; Chowdary, Lingutla R.; Zhang, Jianwei; Tay, Wee Tek; Walsh, Thomas K.; Gordon, Karl H. J.; Heckel, David G.; Downes, Sharon; et al. (NATURE PUBLISHING GROUP, 2018-09-10)
      Evolution of pest resistance threatens the benefits of genetically engineered crops that produce Bacillus thuringiensis (Bt) insecticidal proteins. Strategies intended to delay pest resistance are most effective when implemented proactively. Accordingly, researchers have selected for and analyzed resistance to Bt toxins in many laboratory strains of pests before resistance evolves in the field, but the utility of this approach depends on the largely untested assumption that laboratory-and field-selected resistance to Bt toxins are similar. Here we compared the genetic basis of resistance to Bt toxin Cry2Ab, which is widely deployed in transgenic crops, between laboratory-and field-selected populations of the pink bollworm (Pectinophora gossypiella), a global pest of cotton. We discovered that resistance to Cry2Ab is associated with mutations disrupting the same ATP-binding cassette transporter gene (PgABCA2) in a laboratory-selected strain from Arizona, USA, and in field-selected populations from India. The most common mutation, loss of exon 6 caused by alternative splicing, occurred in resistant larvae from both locations. Together with previous data, the results imply that mutations in the same gene confer Bt resistance in laboratory-and field-selected strains and suggest that focusing on ABCA2 genes may help to accelerate progress in monitoring and managing resistance to Cry2Ab.
    • ABCC2 is associated with Bacillus thuringiensis Cry1Ac toxin oligomerization and membrane insertion in diamondback moth

      Ocelotl, Josue; Sánchez, Jorge; Gómez, Isabel; Tabashnik, Bruce E.; Bravo, Alejandra; Soberón, Mario; Univ Arizona, Dept Entomol (NATURE PUBLISHING GROUP, 2017-05-24)
      Cry1A insecticidal toxins bind sequentially to different larval gut proteins facilitating oligomerization, membrane insertion and pore formation. Cry1Ac interaction with cadherin triggers oligomerization. However, a mutation in an ABC transporter gene (ABCC2) is linked to Cry1Ac resistance in Plutella xylostella. Cry1AcMod, engineered to lack helix alpha-1, was able to form oligomers without cadherinbinding and effectively countered Cry1Ac resistance linked to ABCC2. Here we analyzed Cry1Ac and Cry1AcMod binding and oligomerization by western blots using brush border membrane vesicles (BBMV) from a strain of P. xylostella susceptible to Cry1Ac (Geneva 88) and a strain with resistance to Cry1Ac (NO-QAGE) linked to an ABCC2 mutation. Resistance correlated with lack of specific binding and reduced oligomerization of Cry1Ac in BBMV from NO-QAGE. In contrast, Cry1AcMod bound specifically and still formed oligomers in BBMV from both strains. We compared association of pre-formed Cry1Ac oligomer, obtained by incubating Cry1Ac toxin with a Manduca sexta cadherin fragment, with BBMV from both strains. Our results show that pre-formed oligomers associate more efficiently with BBMV from Geneva 88 than with BBMV from NO-QAGE, indicating that the ABCC2 mutation also affects the association of Cry1Ac oligomer with the membrane. These data indicate, for the first time, that ABCC2 facilitates Cry1Ac oligomerization and oligomer membrane insertion in P. xylostella.
    • Abnormal Capillary Vasodynamics Contribute to Ictal Neurodegeneration in Epilepsy

      Leal-Campanario, Rocio; Alarcon-Martinez, Luis; Rieiro, Hector; Martinez-Conde, Susana; Alarcon-Martinez, Tugba; Zhao, Xiuli; LaMee, Jonathan; Popp, Pamela J. Osborn; Calhoun, Michael E.; Arribas, Juan I.; et al. (NATURE PUBLISHING GROUP, 2017-02-27)
      Seizure-driven brain damage in epilepsy accumulates over time, especially in the hippocampus, which can lead to sclerosis, cognitive decline, and death. Excitotoxicity is the prevalent model to explain ictal neurodegeneration. Current labeling technologies cannot distinguish between excitotoxicity and hypoxia, however, because they share common molecular mechanisms. This leaves open the possibility that undetected ischemic hypoxia, due to ictal blood flow restriction, could contribute to neurodegeneration previously ascribed to excitotoxicity. We tested this possibility with Confocal Laser Endomicroscopy (CLE) and novel stereological analyses in several models of epileptic mice. We found a higher number and magnitude of NG2+ mural-cell mediated capillary constrictions in the hippocampus of epileptic mice than in that of normal mice, in addition to spatial coupling between capillary constrictions and oxidative stressed neurons and neurodegeneration. These results reveal a role for hypoxia driven by capillary blood flow restriction in ictal neurodegeneration.
    • An absolute sodium abundance for a cloud-free ‘hot Saturn’ exoplanet

      Nikolov, N.; Sing, D. K.; Fortney, J. J.; Goyal, J. M.; Drummond, B.; Evans, T. M.; Gibson, N. P.; De Mooij, E. J. W.; Rustamkulov, Z.; Wakeford, H. R.; et al. (NATURE PUBLISHING GROUP, 2018-05-24)
      Broad absorption signatures from alkali metals, such as the sodium (Na I) and potassium (K I) resonance doublets, have long been predicted in the optical atmospheric spectra of cloud-free irradiated gas giant exoplanets(1-3). However, observations have revealed only the narrow cores of these features rather than the full pressure-broadened profiles(4-6). Cloud and haze opacity at the day-night planetary terminator are considered to be responsible for obscuring the absorption-line wings, which hinders constraints on absolute atmospheric abundances(7-9). Here we report an optical transmission spectrum for the 'hot Saturn' exoplanet WASP-96b obtained with the Very Large Telescope, which exhibits the complete pressure-broadened profile of the sodium absorption feature. The spectrum is in excellent agreement with cloud-free, solar-abundance models assuming chemical equilibrium. We are able to measure a precise, absolute sodium abundance of log epsilon(Na) = 6.9(-0.4)(+0.6), and use it as a proxy for the planet's atmospheric metallicity relative to the solar value (Z(p)/Z(circle dot) = 2.3(-1.7)(+8.9)). This result is consistent with the mass-metallicity trend observed for Solar System planets and exoplanets(10-12).
    • Accelerated nonlinear interactions in graded-index multimode fibers

      Eftekhar, M A; Sanjabi-Eznaveh, Z; Lopez-Aviles, H E; Benis, S; Antonio-Lopez, J E; Kolesik, M; Wise, F; Amezcua-Correa, R; Christodoulides, D N; Univ Arizona, Coll Opt Sci (NATURE PUBLISHING GROUP, 2019-04-09)
      Multimode optical fibers have recently reemerged as a viable platform for addressing a number of long-standing issues associated with information bandwidth requirements and power-handling capabilities. As shown in recent studies, the complex nature of such heavily multimoded systems can be effectively exploited to observe altogether novel physical effects arising from spatiotemporal and intermodal linear and nonlinear processes. Here, we study for the first time, accelerated nonlinear intermodal interactions in core-diameter decreasing multimode fibers. We demonstrate that in the anomalous dispersion region, this spatiotemporal acceleration can lead to relatively blue-shifted multimode solitons and blue-drifting dispersive wave combs, while in the normal domain, to a notably flat and uniform supercontinuum, extending over 2.5 octaves. Our results pave the way towards a deeper understanding of the physics and complexity of nonlinear, heavily multimoded optical systems, and could lead to highly tunable optical sources with very high spectral densities.
    • The actin cytoskeletal architecture of estrogen receptor positive breast cancer cells suppresses invasion

      Padilla-Rodriguez, Marco; Parker, Sara S.; Adams, Deanna G.; Westerling, Thomas; Puleo, Julieann I.; Watson, Adam W.; Hill, Samantha M.; Noon, Muhammad; Gaudin, Raphael; Aaron, Jesse; et al. (NATURE PUBLISHING GROUP, 2018-07-30)
      Estrogen promotes growth of estrogen receptor-positive (ER+) breast tumors. However, epidemiological studies examining the prognostic characteristics of breast cancer in postmenopausal women receiving hormone replacement therapy reveal a significant decrease in tumor dissemination, suggesting that estrogen has potential protective effects against cancer cell invasion. Here, we show that estrogen suppresses invasion of ER+ breast cancer cells by increasing transcription of the Ena/VASP protein, EVL, which promotes the generation of suppressive cortical actin bundles that inhibit motility dynamics, and is crucial for the ERmediated suppression of invasion in vitro and in vivo. Interestingly, despite its benefits in suppressing tumor growth, anti-estrogenic endocrine therapy decreases EVL expression and increases local invasion in patients. Our results highlight the dichotomous effects of estrogen on tumor progression and suggest that, in contrast to its established role in promoting growth of ER+ tumors, estrogen has a significant role in suppressing invasion through actin cytoskeletal remodeling.
    • Aeolian abrasion of rocks as a mechanism to produce methane in the Martian atmosphere

      Safi, E; Telling, J; Parnell, J; Chojnacki, M; Patel, M R; Realff, J; Blamey, N J F; Payler, S; Cockell, C S; Davies, L; et al. (NATURE PUBLISHING GROUP, 2019-06-03)
      Seasonal changes in methane background levels and methane spikes have been detected in situ a metre above the Martian surface, and larger methane plumes detected via ground-based remote sensing, however their origin have not yet been adequately explained. Proposed methane sources include the UV irradiation of meteoritic-derived organic matter, hydrothermal reactions with olivine, organic breakdown via meteoroid impact, release from gas hydrates, biological production, or the release of methane from fluid inclusions in basalt during aeolian erosion. Here we quantify for the first time the potential importance of aeolian abrasion as a mechanism for releasing trapped methane from within rocks, by coupling estimates of present day surface wind abrasion with the methane contents of a variety of Martian meteorites, analogue terrestrial basalts and analogue terrestrial sedimentary rocks. We demonstrate that the abrasion of basalt under present day Martian rates of aeolian erosion is highly unlikely to produce detectable changes in methane concentrations in the atmosphere. We further show that, although there is a greater potential for methane production from the aeolian abrasion of certain sedimentary rocks, to produce the magnitude of methane concentrations analysed by the Curiosity rover they would have to contain methane in similar concentrations as economic reserved of biogenic/thermogenic deposits on Earth. Therefore we suggest that aeolian abrasion is an unlikely origin of the methane detected in the Martian atmosphere, and that other methane sources are required.
    • Albedo feedbacks to future climate via climate change impacts on dryland biocrusts

      Rutherford, William A.; Painter, Thomas H.; Ferrenberg, Scott; Belnap, Jayne; Okin, Gregory S.; Flagg, Cody; Reed, Sasha C.; Univ Arizona, Sch Nat Resources & Environm (NATURE PUBLISHING GROUP, 2017-03-10)
      Drylands represent the planet's largest terrestrial biome and evidence suggests these landscapes have large potential for creating feedbacks to future climate. Recent studies also indicate that dryland ecosystems are responding markedly to climate change. Biological soil crusts (biocrusts). soil surface communities of lichens, mosses, and/or cyanobacteria. comprise up to 70% of dryland cover and help govern fundamental ecosystem functions, including soil stabilization and carbon uptake. Drylands are expected to experience significant changes in temperature and precipitation regimes, and such alterations may impact biocrust communities by promoting rapid mortality of foundational species. In turn, biocrust community shifts affect land surface cover and roughness-changes that can dramatically alter albedo. We tested this hypothesis in a full-factorial warming (+ 4 degrees C above ambient) and altered precipitation (increased frequency of 1.2 mm monsoon-type watering events) experiment on the Colorado Plateau, USA. We quantified changes in shortwave albedo via multi-angle, solar-reflectance measurements. Warming and watering treatments each led to large increases in albedo (> 30%). This increase was driven by biophysical factors related to treatment effects on cyanobacteria cover and soil surface roughness following treatment-induced moss and lichen mortality. A rise in dryland surface albedo may represent a previously unidentified feedback to future climate.
    • Alfvénic velocity spikes and rotational flows in the near-Sun solar wind

      Kasper, J C; Bale, S D; Belcher, J W; Berthomier, M; Case, A W; Chandran, B D G; Curtis, D W; Gallagher, D; Gary, S P; Golub, L; et al. (NATURE PUBLISHING GROUP, 2019-12-12)
      The prediction of a supersonic solar wind1 was first confirmed by spacecraft near Earth2,3 and later by spacecraft at heliocentric distances as small as 62 solar radii4. These missions showed that plasma accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy5-7. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams8. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii9-11, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second-considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age12-14.
    • Amplification of waves from a rotating body

      Cromb, Marion; Gibson, Graham M.; Toninelli, Ermes; Padgett, Miles J.; Wright, Ewan M.; Faccio, Daniele; Univ Arizona, Wyant Coll Opt Sci (NATURE PUBLISHING GROUP, 2020-06-22)
      Acoustic waves that carry orbital angular momentum are amplified as they pass through an absorbing disk when the rotation rate exceeds the frequency of the incident wave, thus providing an experimental demonstration of Zel'dovich amplification. In 1971, Zel'dovich predicted that quantum fluctuations and classical waves reflected from a rotating absorbing cylinder will gain energy and be amplified. This concept, which is a key step towards the understanding that black holes may amplify quantum fluctuations, has not been verified experimentally owing to the challenging experimental requirement that the cylinder rotation rate must be larger than the incoming wave frequency. Here, we demonstrate experimentally that these conditions can be satisfied with acoustic waves. We show that low-frequency acoustic modes with orbital angular momentum are transmitted through an absorbing rotating disk and amplified by up to 30% or more when the disk rotation rate satisfies the Zel'dovich condition. These experiments address an outstanding problem in fundamental physics and have implications for future research into the extraction of energy from rotating systems.
    • Androgen receptor-induced integrin α6β1 and Bnip3 promote survival and resistance to PI3K inhibitors in castration-resistant prostate cancer

      Nollet, Eric A; Cardo-Vila, Marina; Ganguly, Sourik S; Tran, Jack D; Schulz, Veronique V; Cress, Anne; Corey, Eva; Miranti, Cindy K; Univ Arizona, Ctr Canc, Dept Cellular & Mol Med (NATURE PUBLISHING GROUP, 2020-06-21)
      The androgen receptor (AR) is the major driver of prostate cancer growth and survival. However, almost all patients relapse with castration-resistant disease (CRPC) when treated with anti-androgen therapy. In CRPC, AR is often aberrantly activated independent of androgen. Targeting survival pathways downstream of AR could be a viable strategy to overcome CRPC. Surprisingly, little is known about how AR drives prostate cancer survival. Furthermore, CRPC tumors in which Pten is lost are also resistant to eradication by PI3K inhibitors. We sought to identify the mechanism by which AR drives tumor survival in CRPC to identify ways to overcome resistance to PI3K inhibition. We found that integrins alpha 6 beta 1 and Bnip3 are selectively elevated in CRPC downstream of AR. While integrin alpha 6 promotes survival and is a direct transcriptional target of AR, the ability of AR to induce Bnip3 is dependent on adhesion to laminin and integrin alpha 6 beta 1-dependent nuclear translocation of HIF1 alpha. Integrins alpha 6 beta 1 and Bnip3 were found to promote survival of CRPC cells selectively on laminin through the induction of autophagy and mitophagy. Furthermore, blocking Bnip3 or integrin alpha 6 beta 1 restored sensitivity to PI3K inhibitors in Pten-negative CRPC. We identified an AR driven pathway that cooperates with laminin and hypoxia to drive resistance to PI3K inhibitors. These findings can help explain in part why PI3K inhibitors have failed in clinical trials to overcome AR-dependent CRPC.
    • Anesthetic Alterations of Collective Terahertz Oscillations in Tubulin Correlate with Clinical Potency: Implications for Anesthetic Action and Post-Operative Cognitive Dysfunction

      Craddock, Travis J. A.; Kurian, Philip; Preto, Jordane; Sahu, Kamlesh; Hameroff, Stuart R.; Klobukowski, Mariusz; Tuszynski, Jack A.; Univ Arizona, Hlth Sci Ctr, Dept Anesthesiol, Ctr Consciousness Studies; Univ Arizona, Hlth Sci Ctr, Dept Psychol, Ctr Consciousness Studies (NATURE PUBLISHING GROUP, 2017-08-29)
      Anesthesia blocks consciousness and memory while sparing non-conscious brain activities. While the exact mechanisms of anesthetic action are unknown, the Meyer-Overton correlation provides a link between anesthetic potency and solubility in a lipid-like, non-polar medium. Anesthetic action is also related to an anesthetic's hydrophobicity, permanent dipole, and polarizability, and is accepted to occur in lipid-like, non-polar regions within brain proteins. Generally the protein target for anesthetics is assumed to be neuronal membrane receptors and ion channels, however new evidence points to critical effects on intra-neuronal microtubules, a target of interest due to their potential role in post-operative cognitive dysfunction (POCD). Here we use binding site predictions on tubulin, the protein subunit of microtubules, with molecular docking simulations, quantum chemistry calculations, and theoretical modeling of collective dipole interactions in tubulin to investigate the effect of a group of gases including anesthetics, non-anesthetics, and anesthetic/convulsants on tubulin dynamics. We found that these gases alter collective terahertz dipole oscillations in a manner that is correlated with their anesthetic potency. Understanding anesthetic action may help reveal brain mechanisms underlying consciousness, and minimize POCD in the choice and development of anesthetics used during surgeries for patients suffering from neurodegenerative conditions with compromised cytoskeletal microtubules.
    • Anisotropic attosecond charge carrier dynamics and layer decoupling in quasi-2D layered SnS2

      Eads, Calley N.; Bandak, Dmytro; Neupane, Mahesh R.; Nordlund, Dennis; Monti, Oliver L. A.; Univ Arizona, Dept Chem & Biochem; Univ Arizona, Dept Phys (NATURE PUBLISHING GROUP, 2017-11-08)
      Strong quantum confinement effects lead to striking new physics in two-dimensional materials such as graphene or transition metal dichalcogenides. While spectroscopic fingerprints of such quantum confinement have been demonstrated widely, the consequences for carrier dynamics are at present less clear, particularly on ultrafast timescales. This is important for tailoring, probing, and understanding spin and electron dynamics in layered and two-dimensional materials even in cases where the desired bandgap engineering has been achieved. Here we show by means of core-hole clock spectroscopy that SnS2 exhibits spin-dependent attosecond charge delocalization times (tau(deloc)) for carriers confined within a layer, tau(deloc) < 400 as, whereas interlayer charge delocalization is dynamically quenched in excess of a factor of 10, tau(deloc) > 2.7 fs. These layer decoupling dynamics are a direct consequence of strongly anisotropic screening established within attoseconds, and demonstrate that important two-dimensional characteristics are also present in bulk crystals of van der Waals-layered materials, at least on ultrafast timescales.
    • An annual time series of weekly size-resolved aerosol properties in the megacity of Metro Manila, Philippines

      Stahl, Connor; Cruz, Melliza Templonuevo; Bañaga, Paola Angela; Betito, Grace; Braun, Rachel A; Aghdam, Mojtaba Azadi; Cambaliza, Maria Obiminda; Lorenzo, Genevieve Rose; MacDonald, Alexander B; Pabroa, Preciosa Corazon; et al. (NATURE PUBLISHING GROUP, 2020-04-29)
      Measurement(s)ion concentration center dot concentration of water-soluble element center dot particulate matter center dot size distribution center dot mass concentration of black carbonTechnology Type(s)ion chromatography center dot inductively coupled plasma mass spectrometry center dot Micro-Orifice Uniform Deposit Impactors (MOUDI) center dot Multi-wavelength Absorption Black Carbon Instrument (MABI) center dot gravimetric analysisFactor Type(s)geographic locationSample Characteristic - LocationNational Capital Region Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12037197 Size-resolved aerosol samples were collected in Metro Manila between July 2018 and October 2019. Two Micro-Orifice Uniform Deposit Impactors (MOUDI) were deployed at Manila Observatory in Quezon City, Metro Manila with samples collected on a weekly basis for water-soluble speciation and mass quantification. Additional sets were collected for gravimetric and black carbon analysis, including during special events such as holidays. The unique aspect of the presented data is a year-long record with weekly frequency of size-resolved aerosol composition in a highly populated megacity where there is a lack of measurements. The data are suitable for research to understand the sources, evolution, and fate of atmospheric aerosols, as well as studies focusing on phenomena such as aerosol-cloud-precipitation-meteorology interactions, regional climate, boundary layer processes, and health effects. The dataset can be used to initialize, validate, and/or improve models and remote sensing algorithms.
    • Anomalous Hall magnetoresistance in a ferromagnet

      Yang, Yumeng; Luo, Ziyan; Wu, Haijun; Xu, Yanjun; Li, Run-Wei; Pennycook, Stephen J.; Zhang, Shufeng; Wu, Yihong; Univ Arizona, Dept Phys (NATURE PUBLISHING GROUP, 2018-06-08)
      The anomalous Hall effect, observed in conducting ferromagnets with broken time-reversal symmetry, offers the possibility to couple spin and orbital degrees of freedom of electrons in ferromagnets. In addition to charge, the anomalous Hall effect also leads to spin accumulation at the surfaces perpendicular to both the current and magnetization direction. Here, we experimentally demonstrate that the spin accumulation, subsequent spin backflow, and spin-charge conversion can give rise to a different type of spin current-related spin current related magnetoresistance, dubbed here as the anomalous Hall magnetoresistance, which has the same angular dependence as the recently discovered spin Hall magnetoresistance. The anomalous Hall magnetoresistance is observed in four types of samples: co-sputtered (Fe1-xMnx)(0.6)Pt-0.4, Fe1-xMnx/Pt multilayer, Fe1-xMnx with x = 0.17-0.65 and Fe, and analyzed using the drift-diffusion model. Our results provide an alternative route to study charge-spin conversion in ferromagnets and to exploit it for potential spintronic applications.
    • ASPP proteins discriminate between PP1 catalytic subunits through their SH3 domain and the PP1 C-tail

      Bertran, M Teresa; Mouilleron, Stéphane; Zhou, Yanxiang; Bajaj, Rakhi; Uliana, Federico; Kumar, Ganesan Senthil; van Drogen, Audrey; Lee, Rebecca; Banerjee, Jennifer J; Hauri, Simon; et al. (NATURE PUBLISHING GROUP, 2019-02-15)
      Serine/threonine phosphatases such as PP1 lack substrate specificity and associate with a large array of targeting subunits to achieve the requisite selectivity. The tumour suppressor ASPP (apoptosis-stimulating protein of p53) proteins associate with PP1 catalytic subunits and are implicated in multiple functions from transcriptional regulation to cell junction remodelling. Here we show that Drosophila ASPP is part of a multiprotein PP1 complex and that PP1 association is necessary for several in vivo functions of Drosophila ASPP. We solve the crystal structure of the human ASPP2/PP1 complex and show that ASPP2 recruits PP1 using both its canonical RVxF motif, which binds the PP1 catalytic domain, and its SH3 domain, which engages the PP1 C-terminal tail. The ASPP2 SH3 domain can discriminate between PP1 isoforms using an acidic specificity pocket in the n-Src domain, providing an exquisite mechanism where multiple motifs are used combinatorially to tune binding affinity to PP1.