bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence of Localized Failure Along Altered Basaltic Blocks in Tectonic Mélange at the Updip Limit of the Seismogenic Zone: Implications for the Shallow Slow Earthquake Source
Authors: Phillips Noah John , Motohashi Ginta , Ujiie Kohtaro , Rowe Christie D.
Published: April 2020

Field studies have led to several interpretations on the mechanics behind slow earthquake phenomena downdip of the seismogenic zone. To date, field studies have not examined the shallow subduction interface which may also host slow earthquake phenomena. We examine a subduction mélange exhumed from conditions representing the source of shallow slow earthquake phenomena. The mélange consists of a shale matrix containing rigid blocks, including basalt which is altered along the margins. Cataclasite‐bearing faults attest to localized faulting along the altered margins of basaltic blocks, concurrent with distributed shear in the shale matrix. These cataclasite‐bearing faults link individual blocks. Microstructures show mutually crosscutting tensile and shear veins, consistent with failure having occurred at, or near, lithostatic pore fluid pressures. We model the stress concentrations around the altered margins of basaltic blocks during distributed shear and show that frictional failure of the altered basalt is predicted to occur at lower imposed strain rates than frictional failure of the shale, favoring fault development along block margins. Calculations of critical nucleation lengths for the blocks show they would fail dynamically at hydrostatic pore fluid pressures, producing microearthquakes. At near‐lithostatic pore fluid pressures, block lengths are below the critical nucleation length for dynamic failure and may produce slow earthquake phenomena. Mixing of velocity‐weakening blocks into a viscously flowing, velocity‐strengthening matrix may serve as a common mechanism for slow earthquake phenomena updip and downdip of the seismogenic zone.
Thermochemical Modification of the Upper Mantle Beneath the Northern Malawi Rift Constrained From Shear Velocity Imaging
Authors: Accardo N. J. , Gaherty J. B. , Shillington D. J. , Hopper E. , Nyblade A. A. , Ebinger C. J. , Scholz C. A. , Chindandali P. R. N. , Wambura‐Ferdinand R. , Mbogoni G. , Russell J. B. , Holtzman B. K. , Havlin C. , Class C.
Published: April 2020

To investigate the controls on continental rifting in the western branch of the East Africa Rift System, we conduct shear velocity imaging of the crust and uppermost mantle beneath the weakly extended Malawi Rift and the Rungwe Volcanic Province (RVP). We use local‐scale measurements of Rayleigh wave phase velocities between 9‐ and 100‐s periods combined with constraints on basin architecture and crustal thickness to invert for shear velocity from the surface to ~135 km. Our resulting 3‐D model reveals a localized low‐velocity anomaly associated with the RVP extending from the crust and through the upper mantle, which can be explained with modestly elevated temperatures. Away from the RVP, velocities within mantle flanking the rift are fast (>4.6 ± 0.1 km/s), suggesting depleted lithospheric mantle to depths of ~100 and >135 km to the west and east of the rift, respectively. The upper mantle beneath the rift axis is characterized by thinned lithosphere with slower velocities than the surrounding plateau, suggestive of thermal and/or chemical modification by the rifting process. Slowest velocities are mildly asymmetric about the rift axis, with the lowest velocities observed beneath the rift and adjacent footwall escarpments. The underlying asthenosphere is only moderately slow (~4.25 ± 0.1 km/s), including beneath the RVP, precluding the presence of significant volumes of partial melt. The positions of localized lithospheric modification and basin‐bounding border faults correlate with the location of Proterozoic mobile belts, suggesting that these sutures provide lithospheric‐scale weakening mechanisms necessary for localizing strain and allowing extension to occur in the Malawi Rift.
Modeled Dynamics of Physical and Biological Processes in the Central California Current System From 1993 to 2016
Authors: Guo Lin , Xiu Peng , Chai Fei , Chavez Francisco P.
Published: April 2020

A three‐dimensional physical‐biological model was used to study the dynamics of physical and biological processes in the central California Current System (CCS) from 1993 to 2016 and investigate its response to different climate modes. The variations of new production (NP) and nitrate fluxes in the central CCS showed robust seasonal and interannual variability. In the coastal upwelling region (0–150 km offshore), the variability of NP was associated with both coastal upwelling and alongshore nitrate advection. In the coastal transition zone (150–300 km offshore), it was related to nitrate fluxes that were determined primarily by the physics rather than nitrate concentration, with vertical mixing and offshore transport being dominant factors. In the offshore oceanic region (California Current; 300–1,000 km offshore), nitrate concentrations played a more important role in the variations of nitrate fluxes, and the NP variability was dominated by the nutrient supplies of vertical mixing and lateral transports. Although El Niño–Southern Oscillation can affect coastal upwelling, alongshore currents, and nitrate fluxes, the coastal NP responded to El Niño–Southern Oscillation mostly in the frequencies of <1 and >6 years. Pacific Decadal Oscillation and North Pacific Gyre Oscillation may affect the CCS ecosystem through large‐scale winds and stratification, modifying the circulation in the upper layer and leading to changes in nitrate concentration and NP.
Contrasted Contribution of Intraseasonal Time Scales to Surface Chlorophyll Variations in a Bloom and an Oligotrophic Regime
Authors: Keerthi M. G. , Levy M. , Aumont O. , Lengaigne M. , Antoine D.
Published: April 2020

Understanding long‐term variations of ocean ecosystems requires untangling the time scales involved in their natural fluctuations. We applied a temporal decomposition procedure to two decades of satellite ocean color observations to characterize the time variability of surface chlorophyll‐a (SChl) in the Mediterranean Sea. In order to assess the reliability of the satellite data at capturing intraseasonal, seasonal, and interannual variability, we first show that satellite SChl data compare well with field data of chlorophyll‐a fluorescence from the long‐term BOUSSOLE time series, at all three time scales. The decomposition procedure is then applied to satellite SChl and to mixing‐layer depth (MxLD) data from an ocean reanalysis, both at the scale of the entire Mediterranean Sea. Our results reveal similar amplitude for the seasonal and intraseasonal SChl variations in the northwestern bloom region, together explaining about 90% of the SChl variance. Coherent seasonal SChl variations occur at the scale of the bloom region (~400 km) and are tightly connected with seasonal MxLD changes. Intraseasonal SChl fluctuations occur at smaller spatial scales (~100 km), suggesting they would be generated by storms although they weakly correlate to variations of the MxLD reanalysis. Over the oligotrophic part of the Mediterranean Sea, about 80% of the variability in both SChl and MxLD are explained by basin‐scale (~1,000 km) seasonal variations. Intraseasonal variability occurs at much smaller spatial scales, typical of mesoscale activity (~30 km). These results support the hypothesis that seasonal SChl variations are driven by changes in MxLD, while mesoscale activity and storms drive the intraseasonal SChl fluctuations.
Slope Gradient Controls Soil Thickness and Chemical Weathering in Subtropical Brazil: Understanding Rates and Timescales of Regional Soilscape Evolution Through a Combination of Field Data and Modeling
Authors: Brosens Liesa , Campforts Benjamin , Robinet Jérémy , Vanacker Veerle , Opfergelt Sophie , Ameijeiras‐Mariño Yolanda , Minella Jean P. G. , Govers Gerard
Published: April 2020

Soil thickness and residence time are regulated by a dynamic interplay between soil formation and lateral transport of soil particles and solutes. To unravel this interplay and infer patterns and rates of chemical weathering, soil physical and chemical properties can be used. Here, we present an integrated approach combining numerical modeling with field measurements to assess the impact of slope gradient on soil thickness and chemical weathering at a regional scale. We first perform a number of synthetic model runs simulating soil formation, weathering, erosion, and deposition, which show that soil thickness and weathering degree decline with increasing slope gradient. We then evaluate how those functional relationships compare to soil‐landscape data observed in the field. Soils are sampled at 100 midslope positions under varying slope gradient. The weathering degree is determined using three chemical weathering indices: ratio of iron oxides to total iron (Fed/Fet), chemical index of alteration (CIA), and total reserve in bases (TRB). Finally, we calibrate the Be2D model to our field data to constrain soil residence times and chemical weathering rates. The modeled weathering rates decrease with increasing soil residence time and decreasing slope gradient. The application of the soil‐landscape evolution model in Southern Brazil shows that weathering rates can vary up to 2 orders of magnitude and depend on hillslope gradient. Notwithstanding model limitations and data uncertainties, we demonstrate the potential of an integrated approach, where field data and numerical modeling are integrated to unravel the timescale of soil weathering along transport over hillslopes.
A Mechanistic Model for Lateral Erosion of Bedrock Channel Banks by Bedload Particle Impacts
Authors: Li Tingan , Fuller Theodore K. , Sklar Leonard S. , Gran Karen B. , Venditti Jeremy G.
Published: April 2020

Bedrock incision plays a key role in determining the pace of landscape evolution. Much is known about how bedrock rivers incise vertically, but less is known about lateral erosion. Lateral erosion is widely thought to occur when the bed is alluviated, which prevents vertical erosion and deflects the downstream transport of bedload particles into channel walls. Here we develop a model for lateral erosion by bedload particle impacts. The lateral erosion rate is the product of the volume eroded per particle impact and the impact rate. The volume eroded per particle impact is modeled by tracking the motion of bedload particles from collision with roughness elements to impacts on the wall. The impact rate on the wall is calculated from deflection rates on roughness elements. The numerical model further incorporates the coevolution of wall morphology, shear stress, and erosion rate. The model predicts the undercut wall shape observed in physical experiments. The nondimensional lateral erosion rate is used to explore how lateral erosion varies under different relative sediment supply (ratio of supply to transport capacity) and transport stage conditions. Maximum lateral erosion rates occur at high relative sediment supply rates (~0.7) and moderate transport stages (~10). The competition between lateral and vertical erosion is investigated by coupling the saltation‐abrasion vertical erosion model with our lateral erosion model. The results suggest that vertical erosion dominates under near 75% of supply and transport stage conditions but is outpaced by lateral erosion near the threshold for full bed coverage.
Age‐Related Climate Response of Tree‐Ring δ13C and δ18O From Spruce in Northwestern China, With Implications for Relative Humidity Reconstructions
Authors: Xu Guobao , Wu Guoju , Liu Xiaohong , Chen Tuo , Wang Bo , Hudson Amy , Trouet Valerie
Published: April 2020

Understanding varying climate responses in tree‐ring data across tree ages is important, but little is known about tree‐age effects on climate responses in tree‐ring stable isotopes. To detect whether age differences in tree‐ring δ13C and δ18O could lead to differing climate responses, we measured tree‐ring cellulose δ13C and δ18O (1901–2010) from Schrenk spruce (Picea schrenkiana) trees in northwestern China with ages ranging from 110 to 470 years, which we binned into three age groups. Tree‐ring δ13C (pin‐corrected) and δ18O exhibited similar year‐to‐year variability between age groups and did not feature age‐related trends. δ13C series from old trees (270–470 years) showed stronger legacy effects, reflecting influences from the antecedent period (due to carbohydrate reserves and climate), compared to young trees (110–125 years). Both tree‐ring δ13C and δ18O values decreased with increasing relative humidity (RH) and precipitation and with decreasing mean and maximum temperatures during the main growing season (May–August). δ13C and δ18O exhibited age‐dependent climate responses: Young trees had a stronger climate response in δ13C but a weaker or similar climate response in δ18O compared to old trees. We developed multiple growing‐season RH reconstructions based on composite chronologies using δ13C and δ18O series from different age groups. In particular, we found that including δ13C from young trees improved the skill of RH reconstructions because of the age‐specific mechanisms driving the δ13C‐climate relationship, but that caution is warranted with regard to extreme values. We therefore suggest that young trees should be considered when using stable isotopes, particularly in δ13C, for climate reconstruction.
Systematic Assessment of Retrieval Methods for Canopy Far‐Red Solar‐Induced Chlorophyll Fluorescence Using High‐Frequency Automated Field Spectroscopy
Authors: Chang Christine Y. , Guanter Luis , Frankenberg Christian , Köhler Philipp , Gu Lianhong , Magney Troy S. , Grossmann Katja , Sun Ying
Published: April 2020

Remote sensing of solar‐induced chlorophyll fluorescence (SIF) offers potential to infer photosynthesis across scales and biomes. Many retrieval methods have been developed to estimate top‐of‐canopy SIF using ground‐based spectroscopy. However, inconsistencies among methods may confound interpretation of SIF dynamics, eco‐physiological/environmental drivers, and its relationship with photosynthesis. Using high temporal‐ and spectral resolution ground‐based spectroscopy, we aimed to (1) evaluate performance of SIF retrieval methods under diverse sky conditions using continuous field measurements; (2) assess method sensitivity to fluctuating light, reflectance, and fluorescence emission spectra; and (3) inform users for optimal ground‐based SIF retrieval. Analysis included field measurements from bi‐hemispherical and hemispherical‐conical systems and synthetic upwelling radiance constructed from measured downwelling radiance, simulated reflectance, and simulated fluorescence for benchmarking. Fraunhofer‐based differential optical absorption spectroscopy (DOAS) and singular vector decomposition (SVD) retrievals exhibit convergent SIF‐PAR relationships and diurnal consistency across different sky conditions, while O2A‐based spectral fitting method (SFM), SVD, and modified Fraunhofer line discrimination (3FLD) exhibit divergent SIF‐PAR relationships across sky conditions. Such behavior holds across system configurations, though hemispherical‐conical systems diverge less across sky conditions. O2A retrieval accuracy, influenced by atmospheric distortion, improves with a narrower fitting window and when training SVD with temporally local spectra. This may impact SIF‐photosynthesis relationships interpreted by previous studies using O2A‐based retrievals with standard (759–767.76 nm) fitting windows. Fraunhofer‐based retrievals resist atmospheric impacts but are noisier and more sensitive to assumed SIF spectral shape than O2A‐based retrievals. We recommend SVD or SFM using reduced fitting window (759.5–761.5 nm) for robust far‐red SIF retrievals across sky conditions.
Outgoing Near‐Infrared Radiation From Vegetation Scales With Canopy Photosynthesis Across a Spectrum of Function, Structure, Physiological Capacity, and Weather
Authors: Baldocchi Dennis D. , Ryu Youngryel , Dechant Benjamin , Eichelmann Elke , Hemes Kyle , Ma Siyan , Sanchez Camilo Rey , Shortt Robert , Szutu Daphne , Valach Alex , Verfaillie Joe , Badgley Grayson , Zeng Yelu , Berry Joseph A.
Published: April 2020

We test the relationship between canopy photosynthesis and reflected near‐infrared radiation from vegetation across a range of functional (photosynthetic pathway and capacity) and structural conditions (leaf area index, fraction of green and dead leaves, canopy height, reproductive stage, and leaf angle inclination), weather conditions, and years using a network of field sites from across central California. We based our analysis on direct measurements of canopy photosynthesis, with eddy covariance, and measurements of reflected near‐infrared and red radiation from vegetation, with light‐emitting diode sensors. And we interpreted the observed relationships between photosynthesis and reflected near‐infrared radiation using simulations based on the multilayer, biophysical model, CanVeg. Measurements of reflected near‐infrared radiation were highly correlated with measurements of canopy photosynthesis on half‐hourly, daily, seasonal, annual, and decadal time scales across the wide range of function and structure and weather conditions. Slopes of the regression between canopy photosynthesis and reflected near‐infrared radiation were greatest for the fertilized and irrigated C4 corn crop, intermediate for the C3 tules on nutrient‐rich organic soil and nitrogen fixing alfalfa, and least for the native annual grasslands and oak savanna on nutrient‐poor, mineral soils. Reflected near‐infrared radiation from vegetation has several advantages over other remotely sensed vegetation indices that are used to infer canopy photosynthesis; it does not saturate at high leaf area indices, it is insensitive to the presence of dead legacy vegetation, the sensors are inexpensive, and the reflectance signal is strong. Hence, information on reflected near‐infrared radiation from vegetation may have utility in monitoring carbon assimilation in carbon sequestration projects or on microsatellites orbiting Earth for precision agriculture applications.
Ensemble‐Based Neural Network Modeling for Hydrologic Forecasts: Addressing Uncertainty in the Model Structure and Input Variable Selection
Authors: Kim Taereem , Shin Ju‐Young , Kim Hanbeen , Heo Jun‐Haeng
Published: April 2020

Artificial neural networks (ANNs) have been extensively used to forecast monthly precipitation for water resources management over the past few decades. Efforts to produce more accurate and stable forecasts face ongoing challenges as the so‐called single‐ANN (S‐ANN) approach has several limitations, particularly regarding uncertainty. Many attempts have been made to deal with different types of uncertainties by applying ensemble approaches. Here, we propose a new ANN ensemble model (ANN‐ENS) dealing with uncertainty in model structure and input variable selection to provide a more accurate and stable forecasting performance. This model is structured by generating various input layers, considering all the candidate input variables (i.e.,large‐scale climate indices and lagged precipitation). We developed a modified backward elimination method to select the preliminary input variables from all the candidate input variables. Then, we tested and validated the proposed ANN‐ENS using observed monthly precipitation from 10 meteorological stations in the Han River basin, South Korea. Our results demonstrated that the ANN‐ENS enhanced the forecasting performance in terms of both accuracy and stability. Although a significant uncertainty was introduced by using all the candidate input variables, the forecasting result outperformed S‐ANNs for all employed stations. Additionally, the ANN‐ENS provided a more stable forecasting performance in comparison with S‐ANNs, which are highly sensitive. Moreover, the generated ensemble members were slightly biased at some stations but were generally reliable.
Lessons from a Post-Eruption Landscape
Authors: Major Jon , Crisafulli Charles , Swanson Frederick
Published: April 2020

Four decades of research into biophysical responses to the 1980 eruption of Mount St. Helens have vastly improved our understanding of how landscapes react to cataclysmic disturbances.
Investigating the Spark
Authors: Goss Heather
Published: April 2020

In May, we look at lightning—what it tells us about dangerous weather, how to find it on other planets, and what we might learn if we get all that data in one place.
Assessing Origins of End‐Triassic Tholeiites From Eastern North America Using Hafnium Isotopes
Authors: Elkins Lynne J. , Meyzen Christine M. , Callegaro Sara , Marzoli Andrea , Bizimis Michael
Published: April 2020

The driving processes responsible for producing the Central Atlantic Magmatic Province, the Large Igneous Province associated with end‐Triassic rifting of Pangea, remain largely debated. Because their compositions encompass most of the Central Atlantic basalt spectrum, tholeiites from southern Eastern North America are considered pivotal for identifying magma origins. New 176Hf/177Hf measurements for 201 Ma Eastern North American tholeiites dominantly record a local petrogenetic history. Their εHf ratios, corrected to an emplacement age of 201 Ma (−7.85 to +5.86), form a positive but shallowly sloped array slightly deviating from the terrestrial array on a εHf versus εNd diagram. Comparison of 176Hf/177Hf to other isotope ratios and trace elements helps to rule out several petrogenetic scenarios, particularly mixing of melts from global depleted or enriched mantle components. In contrast, partial melting of subduction‐metasomatized mantle can explain the parental magma composition for southern Eastern North America. Such metasomatism likely occurred during Paleozoic subduction around Pangea and may have been dominated by sediment‐derived fluid reactions. The observed 176Hf/177Hf versus 143Nd/144Nd array may reflect subsequent assimilation of lower continental crust, perhaps together with limited direct melting of recycled continental crust in the asthenosphere. The proposed recycling scenario does not specifically support or preclude a mantle plume origin for the Central Atlantic Magmatic Province but instead points toward the presence of a distinct local mantle source and crustal assimilation processes during magma transport. Detailed understanding of these local effects is needed in order to more accurately understand the origins of Large Igneous Provinces.
Strength and Spatial Structure of the Perturbation Induced by a Tropical Cyclone to the Underlying Eddies
Authors: Lu Zhumin , Wang Guihua , Shang Xiaodong
Published: April 2020

A tropical cyclone (TC) induces the oceanic geostrophic response, which perturbs the underlying ocean eddy field. This study investigates the strength and spatial structure of isopycnal undulations and potential vorticity (PV) changes linked with the geostrophic response by use of a linear, two‐layer theory and an OGCM. It is found that the strength and cross‐track length scale of the geostrophic response are well compared with those of background eddies, highlighting the ability of a TC to perturb underlying ocean eddies. More importantly, the TC‐induced PV perturbation is confined within the thermocline between 100 and 300 m depth, causing the 3D quasi‐geostrophic evolution of the perturbed eddies. The length scale of upwelling perturbation (which is ~130 km) is larger than that of PV response (~50 km). This scale disparity means that the patterns of the TC‐induced perturbations are subject to eddy‐TC separation distance. Consequently, the perturbation of a TC to an eddy is significant (negligible) when the eddy‐TC separation distance is less than 80 km (larger than 200 km). This study provides a starting point for understanding the TC‐induced 3D evolution of the perturbed ocean eddy field.
Soundscape of a Narwhal Summering Ground in a Glacier Fjord (Inglefield Bredning, Greenland)
Authors: Podolskiy Evgeny A. , Sugiyama Shin
Published: April 2020

Narwhal acoustic phonation is embedded in the icy cacophony of one of the noisiest soundscapes in the ocean. The high susceptibility of the narwhal to climate change highlights the need for further efforts to document baseline descriptions of the sounds it produces, especially given the potential anthropogenic impacts on their habitats. However, observations are rare, and narwhal acoustic behavior and habitats are poorly understood (attributed to both the skittish nature of hard‐to‐approach narwhals and the difficult access to remote and often dangerous glacier fjords). Here, we provide acoustic measurements in a narwhal summering ground in glacial fjords in Northwest Greenland that were mainly collected during Inuit hunting expeditions. This unique observational strategy near a key narwhal hot spot allowed the acquisition of supervised near‐source recordings of narwhal vocalizations, which confirms the animal's presence within several hundred meters of an actively calving Bowdoin Glacier. We accurately describe the acoustic signals and noise related to the cetacean, environmental, and anthropogenic sources, show previously unreported signals and their properties, report elevated background noise levels near the calving front, and discuss the general soundscape features of a glacier fjord. The baseline information presented here should encourage long‐term follow‐up acoustic monitoring in the area and provides an important reference for comparisons with future conditions and other regions. We also anticipate that our work will be a starting point both for the development of criteria to distinguish pulsed calls from terminal buzzes and for a thorough discussion of the dual use of passive acoustic monitoring in traditional hunting practices.
Atmospheric and Oceanographic Signatures in the Ice Shelf Channel Morphology of Roi Baudouin Ice Shelf, East Antarctica, Inferred From Radar Data
Authors: Drews R. , Schannwell C. , Ehlers T. A. , Gladstone R. , Pattyn F. , Matsuoka K.
Published: April 2020

Ice shelves around Antarctica can provide back stress for outlet glaciers and control ice sheet mass loss. They often contain narrow bands of thin ice termed ice shelf channels. Ice shelf channel morphology can be interpreted through surface depressions and exhibits junctions and deflections from flowlines. Using ice flow modeling and radar, we investigate ice shelf channels in the Roi Baudouin Ice Shelf. These are aligned obliquely to the prevailing easterly winds. In the shallow radar stratigraphy, syncline and anticline stacks occur beneath the upwind and downwind side, respectively. The structures are horizontally and vertically coherent, except near an ice shelf channel junction where patterns change structurally with depth. Deeper layers truncate near basal incisions. Using ice flow modeling, we show that the stratigraphy is ∼9 times more sensitive to atmospheric variability than to oceanic variability. This is due to the continual adjustment toward flotation. We propose that syncline‐anticline pairs in the shallow stratigraphy are caused by preferential snow deposition on the windward side and wind erosion at the downwind side. This drives downwind deflection of ice shelf channels of several meters per year. The depth variable structures indicate formation of an ice shelf channel junction by basal melting. We conclude that many ice shelf channels are seeded at the grounding line. Their morphology farther seaward is shaped on different length scales by ice dynamics, the ocean, and the atmosphere. These processes act on finer (subkilometer) scales than are captured by most ice, atmosphere, and ocean models, yet the dynamics of ice shelf channels may have broader implications for ice shelf stability.
High-speed femtosecond laser plasmonic lithography and reduction of graphene oxide for anisotropic photoresponse
Authors: Zou Tingting , Zhao Bo , Xin Wei , Wang Ye , Wang Bin , Zheng Xin , Xie Hongbo , Zhang Zhiyu , Yang Jianjun , Guo Chunlei
Published: April 2020

Micro/nanoprocessing of graphene surfaces has attracted significant interest for both science and applications due to its effective modulation of material properties, which, however, is usually restricted by the disadvantages of the current fabrication methods. Here, by exploiting cylindrical focusing of a femtosecond laser on graphene oxide (GO) films, we successfully produce uniform subwavelength grating structures at high speed along with a simultaneous in situ photoreduction process. Strikingly, the well-defined structures feature orientations parallel to the laser polarization and significant robustness against distinct perturbations. The proposed model and simulations reveal that the structure formation is based on the transverse electric (TE) surface plasmons triggered by the gradient reduction of the GO film from its surface to the interior, which eventually results in interference intensity fringes and spatially periodic interactions. Further experiments prove that such a regular structured surface can cause enhanced optical absorption (>20%) and an anisotropic photoresponse (~0.46 ratio) for the reduced GO film. Our work not only provides new insights into understanding the laser-GO interaction but also lays a solid foundation for practical usage of femtosecond laser plasmonic lithography, with the prospect of expansion to other two-dimensional materials for novel device applications.
Visible light communication with efficient far-red/near-infrared polymer light-emitting diodes
Authors: Minotto Alessandro , Haigh Paul A. , Łukasiewicz Łukasz G. , Lunedei Eugenio , Gryko Daniel T. , Darwazeh Izzat , Cacialli Franco
Published: April 2020

Visible light communication (VLC) is a wireless technology that relies on optical intensity modulation and is potentially a game changer for internet-of-things (IoT) connectivity. However, VLC is hindered by the low penetration depth of visible light in non-transparent media. One solution is to extend operation into the “nearly (in)visible” near-infrared (NIR, 700–1000 nm) region, thus also enabling VLC in photonic bio-applications, considering the biological tissue NIR semitransparency, while conveniently retaining vestigial red emission to help check the link operativity by simple eye inspection. Here, we report new far-red/NIR organic light-emitting diodes (OLEDs) with a 650–800 nm emission range and external quantum efficiencies among the highest reported in this spectral range (>2.7%, with maximum radiance and luminance of 3.5 mW/cm2 and 260 cd/m2, respectively). With these OLEDs, we then demonstrate a “real-time” VLC setup achieving a data rate of 2.2 Mb/s, which satisfies the requirements for IoT and biosensing applications. These are the highest rates ever reported for an online unequalised VLC link based on solution-processed OLEDs.
Ionomycin ameliorates hypophosphatasia via rescuing alkaline phosphatase deficiency-mediated L-type Ca2+ channel internalization in mesenchymal stem cells
Authors: Li Bei , He Xiaoning , Dong Zhiwei , Xuan Kun , Sun Wei , Gao Li , Liu Shiyu , Liu Wenjia , Hu Chenghu , Zhao Yimin , Shi Songtao , Jin Yan
Published: April 2020

The loss-of-function mutations in the ALPL result in hypophosphatasia (HPP), an inborn metabolic disorder that causes skeletal mineralization defects. In adults, the main clinical features are early loss of primary or secondary teeth, osteoporosis, bone pain, chondrocalcinosis, and fractures. However, guidelines for the treatment of adults with HPP are not available. Here, we show that ALPL deficiency caused a reduction in intracellular Ca2+influx, resulting in an osteoporotic phenotype due to downregulated osteogenic differentiation and upregulated adipogenic differentiation in both human and mouse bone marrow mesenchymal stem cells (BMSCs). Increasing the intracellular level of calcium in BMSCs by ionomycin treatment rescued the osteoporotic phenotype inalpl+/−mice and BMSC-specific (Prrx1-alpl−/−) conditional alpl knockout mice. Mechanistically, ALPL was found to be required for the maintenance of intracellular Ca2+influx, which it achieves by regulating L-type Ca2+channel trafficking via binding to the α2δ subunits to regulate the internalization of the L-type Ca2+channel. Decreased Ca2+flux inactivates the Akt/GSK3β/β-catenin signaling pathway, which regulates lineage differentiation of BMSCs. This study identifies a previously unknown role of the ectoenzyme ALPL in the maintenance of calcium channel trafficking to regulate stem cell lineage differentiation and bone homeostasis. Accelerating Ca2+flux through L-type Ca2+channels by ionomycin treatment may be a promising therapeutic approach for adult patients with HPP.
Trends in cervical cancer incidence in sub-Saharan Africa
Authors: Jedy-Agba Elima , Joko Walburga Yvonne , Liu Biying , Buziba Nathan Gyabi , Borok Margaret , Korir Anne , Masamba Leo , Manraj Shyam Shunker , Finesse Anne , Wabinga Henry , Somdyala Nontuthuzelo , Parkin Donald Maxwell
Published: April 2020

Background

Cervical cancer is the second most common cancer and the leading cause of cancer death in women in sub-Saharan Africa (SSA).

Methods

Trends in the incidence of cervical cancer are examined for a period of 10–25 years in 10 population-based cancer registries across eight SSA countries (Gambia, Kenya, Malawi, Mauritius, Seychelles, South Africa, Uganda and Zimbabwe). A total of 21,990 cases of cervical cancer were included in the analyses.

Results

Incidence rates had increased in all registries for some or all of the periods studied, except for Mauritius with a constant annual 2.5% decline. Eastern Cape and Blantyre (Malawi) registries showed significant increases over time, with the most rapid being in Blantyre (7.9% annually). In Kampala (Uganda), a significant increase was noted (2.2%) until 2006, followed by a non-significant decline. In Eldoret, a decrease (1998–2002) was followed by a significant increase (9.5%) from 2002 to 2016.

Conclusion

Overall, cervical cancer incidence has been increasing in SSA. The current high-level advocacy to reduce the burden of cervical cancer in SSA needs to be translated into support for prevention (vaccination against human papillomavirus and population-wide screening), with careful monitoring of results through population-based registries.
LncRNA-HNF1A-AS1 functions as a competing endogenous RNA to activate PI3K/AKT signalling pathway by sponging miR-30b-3p in gastric cancer
Authors: Liu Hai-Ting , Ma Ran-Ran , Lv Bei-Bei , Zhang Hui , Shi Duan-Bo , Guo Xiang-Yu , Zhang Guo-Hao , Gao Peng
Published: April 2020

Background

Accumulating evidence demonstrated that long noncoding RNAs (lncRNAs) played important regulatory roles in many cancer types. However, the role of lncRNAs in gastric cancer (GC) progression remains unclear.

Methods

RT-qPCR assay was performed to detect the expression of HNF1A-AS1 in gastric cancer tissues and the non-tumourous gastric mucosa. Overexpression and RNA interference approaches were used to investigate the effects of HNF1A-AS1 on GC cells. Insight into competitive endogenous RNA (ceRNA) mechanisms was gained via bioinformatics analysis, luciferase assays and an RNA-binding protein immunoprecipitation (RIP) assay, RNA-FISH co-localisation analysis combined with microRNA (miRNA)-pulldown assay.

Results

This study displayed that revealed expression of HNF1A-AS1 was associated with positive lymph node metastasis in GC. Moreover, HNF1A-AS1 significantly promoted gastric cancer invasion, metastasis, angiogenesis and lymphangiogenesis in vitro and in vivo. In addition, HNF1A-AS1 was demonstrated to function as a ceRNA for miR-30b-3p. HNF1A-AS1 abolished the function of the miRNA-30b-3p and resulted in the derepression of its target, PIK3CD, which is a core oncogene involved in the progression of GC.

Conclusion

This study demonstrated that HNF1A-AS1 worked as a ceRNA and promoted PI3K/AKT signalling pathway-mediated GC metastasis by sponging miR-30b-3p, offering novel insights of the metastasis mechanism in GC.
11β hydroxysteroid dehydrogenase 1: a new marker for predicting response to immune-checkpoint blockade therapy in non-small-cell lung carcinoma
Authors: Saito Ryoko , Miki Yasuhiro , Abe Takuto , Miyauchi Eisaku , Abe Jiro , Nanamiya Ren , Inoue Chihiro , Sato Ikuro , Sasano Hironobu
Published: April 2020

Background

Understanding the status of intratumoural immune microenvironment is necessary to ensure the efficacy of immune-checkpoint (IC) blockade therapy. Cortisol plays pivotal roles in glucocorticoid interactions in the immune system. We examined the correlation between intratumourally synthesised cortisol through 11β hydroxysteroid dehydrogenase (HSD) 1 and the immune microenvironment in non-small-cell lung carcinoma (NSCLC).

Methods

We correlated 11βHSD1 immunoreactivity in 125 cases of NSCLC with the amount of intratumoural immune cells present, and 11βHSD1 immunoreactivity with the efficacy of IC blockade therapy in 18 specimens of NSCLC patients. In vitro studies were performed to validate the immunohistochemical examination.

Results

11βHSD1 immunoreactivity showed a significant inverse correlation with the number of tumour-infiltrating lymphocytes and CD3- or CD8-positive T cells. 11βHSD1 immunoreactivity tended to be inversely correlated with the clinical efficacy of the IC blockade therapy. In vitro studies revealed that 11βHSD1 promoted the intratumoural synthesis of cortisol. This resulted in a decrease in cytokines and in the inhibition of monocyte migration.

Conclusions

Our study is the first report clarifying the inhibitory effects of intratumourally synthesised cortisol through 11βHSD1 on immune cell migration. We propose that the response to IC blockade therapy in NSCLC may be predicted by 11βHSD1.
Clinically high-risk breast cancer displays markedly discordant molecular risk predictions between the MammaPrint and EndoPredict tests
Authors: Jahn Stephan Wenzel , Bösl Andreas , Tsybrovskyy Oleksiy , Gruber-Rossipal Christine , Helfgott Ruth , Fitzal Florian , Knauer Michael , Balic Marija , Jasarevic Zerina , Offner Felix , Moinfar Farid
Published: April 2020

Inter-test concordance between the MammaPrint and the EndoPredict tests used to predict the risk of recurrence in breast cancer was evaluated in 94 oestrogen receptor-positive, HER2-negative breast cancers. We correlated histopathological data with clinical risk estimation as defined in the MINDACT trial. 42.6% (40/94) of cases were high-risk by MammaPrint, 44.7% (42/94) by EndoPredict (EPclin), and 45.7% (43/94) by clinical risk definition. Thirty-six percent of genomic risk predictions were discordant with a low inter-test correlation between EndoPredict and MammaPrint (p = 0.012; κ = 0.27, 95% CI [0.069, 0.46]). Clinical risk stratification did not correlate with MammaPrint (p = 0.476) but highly correlated with EndoPredict (p < 0.001). Consequently, clinically high-risk tumours (n = 43) were more frequently high-risk by EndoPredict than by MammaPrint (76.6% vs. 46.5%, p = 0.004), with 44% of cases discordantly classified and no significant association between genomic risk predictions (p = 0.294). Clinicians need to be aware that clinical pre-stratification can profoundly influence multigenomic test performance.
Targeted therapy for mTORC1-driven tumours through HDAC inhibition by exploiting innate vulnerability of mTORC1 hyper-activation
Authors: Yang Fuchun , Sun Shaogang , Wang Chenran , Haas Michael , Yeo Syn , Guan Jun-Lin
Published: April 2020

Backgound

The mechanistic target of rapamycin complex 1 (mTORC1) is important in the development and progression of many cancers. Targeted cancer therapy using mTORC1 inhibitors is used for treatment of cancers; however, their clinical efficacies are still limited.

Methods

We recently created a new mouse model for human lymphangiosarcoma by deleting Tsc1 in endothelial cells and consequent hyper-activation of mTORC1. Using Tsc1iΔEC tumour cells from this mouse model, we assessed the efficacies of histone deacetylase (HDAC) inhibitors as anti-tumour agents for mTORC1-driven tumours.

Results

Unlike the cytostatic effect of mTORC1 inhibitors, HDAC inhibitors induced Tsc1iΔEC tumour cell death in vitro and their growth in vivo. Analysis of several HDAC inhibitors suggested stronger anti-tumour activity of class I HDAC inhibitor than class IIa or class IIb inhibitors, but these or pan HDAC inhibitor SAHA did not affect mTORC1 activation in these cells. Moreover, HDAC inhibitor-induced cell death required elevated autophagy, but was not affected by disrupting caspase-dependent apoptosis pathways. We also observed increased reactive oxygen species and endoplasmic reticulum stress in SAHA-treated tumour cells, suggesting their contribution to autophagic cell death, which were dependent on mTORC1 hyper-activation.

Conclusion

These studies suggest a potential new treatment strategy for mTORC1-driven cancers like lymphangiosarcoma through an alternative mechanism.
Pregnancy-related risk factors for sex cord-stromal tumours and germ cell tumours in parous women: a registry-based study
Authors: Sköld Camilla , Bjørge Tone , Ekbom Anders , Engeland Anders , Gissler Mika , Grotmol Tom , Madanat-Harjuoja Laura , Ording Anne Gulbech , Trabert Britton , Tretli Steinar , Troisi Rebecca , Sørensen Henrik Toft , Glimelius Ingrid
Published: April 2020

Background

Non-epithelial ovarian cancers are divided into sex cord-stromal tumours (SCSTs) and germ cell tumours (GCTs). Whereas parity and other pregnancy-related factors are protective for epithelial ovarian cancer, their associations with SCSTs and GCTs remains unclear.

Methods

Using data from the medical birth registries from Denmark, Finland, Norway and Sweden, we compared all parous women with a diagnosis of SCSTs (n = 420) or GCTs (n = 345) 1970–2013 with up to 10 parous controls (SCSTs n = 4041; GCTs n = 2942) matched on the cases’ birth year and country. We used conditional logistic regression to estimate odds ratios (ORs) with 95% confidence intervals (CIs) of associations between pregnancy-related factors and SCSTs and GCTs.

Results

The risk of SCSTs, but not GCTs, decreased with higher age at last birth [≥40 versus <25 years: OR 0.48 (95% CI 0.23–0.98)]. The risk of SCSTs (but not GCTs) also decreased with shorter time since last birth. Number of births, preterm birth, preeclampsia, and offspring size were not associated with risk of SCSTs or GCTs.

Conclusions

We found a decreased risk of SCSTs with higher age at last birth and shorter time since last birth. The risk of SCSTs (but not GCTs) may be influenced by the woman’s reproductive history.
Jiaogulan tea (Gpostemma pentaphyllum) potentiates the antidiabetic effect of white tea via the AMPK and PI3K pathways in C57BL/6 mice
Authors: Xia Xiaoyan , Xu Jing , Wang Xude , Wang Hua , Lin Zhenchuan , Shao Keping , Fang LinLin , Zhang Chenning , Zhao Yuqing
Published: April 2020

The use of plant-based beverages to interfere with the onset of diabetes may be a promising approach towards type 2 diabetes mellitus (T2DM).
Ru/g-C3N4 as an efficient catalyst for selective hydrogenation of aromatic diamines to alicyclic diamines
Authors: Cao Junya , Han Fenggang , Wang Liguo , Huang Xiaoyu , Cao Yan , He Peng , Yang Huanhuan , Chen Jiaqiang , Li Huiquan
Published: April 2020

A series of Ru/g-C3N4 materials with highly dispersed Ru were firstly prepared by an ultrasonic impregnation method using carbon nitride as a support.
Research on distributed blockchain‐based privacy‐preserving and data security framework in IoT
Authors: Tian Hongliang , Ge Xiaonan , Wang Jiayue , Li Chenxi , Pan Hongle
Published: April 2020

With the rapid development of the Internet of things (IoT), it has brought great convenience for people's life. However, the security and privacy of IoT still face a major challenge. To remedy these issues, in this study, the authors first introduce the three‐tier architecture of IoT and analyse the corresponding security problems of each layer, then they discussed the compatibility between IoT and blockchain. Secondly, they propose a new, distributed blockchain‐based security architecture of IoT, which rely on gateway nodes of perception layer to secure data storage and sharing, and use middleware servers to analyse and process data. Finally, they adopt game theory to model and analyse their designed scheme. The results demonstrate that their scheme is a safe and deployable framework for IoT data security and privacy.
Prospective Leads from Endophytic Fungi for Anti-Inflammatory Drug Discovery
Authors: Pal Pragya Paramita , Shaik Ameer Basha , Begum A. Sajeli
Published: April 2020

A wide array of therapeutic effects has been exhibited by compounds isolated from natural sources. “Bio-actives of endophytic origin” is a recently explored area that came into recognition over the last 2 decades. Literature search on the secondary metabolites of endophytes have shown several pharmacologically active compounds especially anti-inflammatory compounds, which have been reviewed in the present paper. The article is structured based on the chemical classification of secondary metabolites. The compounds were identified to possess activity against a total of 16 anti-inflammatory targets. The most common targets involved were NO, TNF-α, and inhibition of total ROS. Further, the article gives a detailed insight into the compounds, their endophytic source, and anti-inflammatory target as well as potency. The contents of the article cover all the scientific reports published until Feb. 2019. Thus 118 compounds and 6 extracts have been reported to be obtained
from endophytic sources showing anti-inflammatory activities. Amongst these, herbarin, periconianone A, and periconianone B were identified as the most potent compounds in terms of their IC50 values against NO inhibition.
EFFECTIVENESS OF AN INFORMATION BOOKLET ON HOME REMEDIAL MEASURES FOR BREAST ENGORGEMENT
Authors: Eapen Sherin Sara , Philomena Fernandes
Published: April 2020

The study was conducted to evaluate the effectiveness of an information booklet on Home remedial measures for breast engorgement among postnatal mothers. An evaluative approach with one group Pre test Post test design was used for the study. 40 samples were selected using simple random sampling method. The present study was conducted in Justice K. S. Hegde Charitable hospital Mangalore. The collected data were analysed using descriptive and inferential statistics. A significant difference between Pre test and Post test knowledge was found (t=14.788,p<0.05). The study findings showed that the information booklet was highly effective in improving knowledge of the postnatal mothers by providing an information booklet on home remedial measures for breast engorgement. There was no significant association between the level of knowledge and demographic variables such as age, residing area, educational status, source of information, occupational status, parity.