bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of phosphomolybdic acid on the catalytic behavior of bifunctional Pt‐Cr/nanocrystalline Y zeolite in hydroisomerization of n‐octane
Authors: Afzali Zahra , Vaezi Mohammad Reza , Aghabarari Behzad , Martinez Huerta Maria Victoria 
Published: July 2019

AbstractIn this study, Y zeolite nanocrystals were synthesized without an organic template and were used as a support for bifunctional nanocatalysts in the hydroisomerization of n‐octane. Different types of catalysts were synthesized by loading Pt, Cr, and phosphomolybdic acid (HPMo) on Y zeolite nanocrystal supports and were characterized by X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET), field emission scanning electron microscope (FE‐SEM), and transmission electron microscope (TEM) analysis. The Cr‐Pt/HPMo‐Y nanocatalyst with a surface area of approx. 600 m2/g showed the best performance in the hydroisomerization of n‐octane. The optimization of n‐octane hydroisomerization over bifunctional nanocatalysts supported on nanocrystalline Y zeolite, in the presence of H2 gas, was applied based on the response surface methodology (RSM) and Box–Behnken design (BBD) template. The effect of three different process variables on the yield of iso‐alkanes as the purpose process was determined. Experiments were carried out using a fixed‐bed microreactor under different ranges of weight hourly space velocity (WHSV) (A = 0.5–1.5 hr−1), H2 to n‐C8 molar ratio (B = 1:1–3:1), and reaction temperature (C = 200–300°C). The RSM proved that the temperature variable had the greatest impact on the hydroisomerization reaction yield.
Dysfunctional striatal dopamine signaling in Huntington's disease
Authors: Koch Ellen T. , Raymond Lynn A. 
Published: July 2019

AbstractDopamine signaling in the striatum is critical for a variety of behaviors including movement, behavioral flexibility, response to reward and many forms of learning. Alterations to dopamine transmission contribute to pathological features of many neurological diseases, including Huntington's disease (HD). HD is an autosomal dominant genetic disorder caused by a CAG repeat expansion in the Huntingtin gene. The striatum is preferentially degenerated in HD, and this region receives dopaminergic input from the substantia nigra. Studies of HD patients and genetic rodent models have shown changes to levels of dopamine and its receptors in the striatum, and alterations in dopamine receptor signaling and modulation of other neurotransmitters, notably glutamate. Throughout his career, Dr. Michael Levine's research has furthered our understanding of dopamine signaling in the striatum of healthy rodents and HD mouse models. This review will focus on the work of his group and others in elucidating alterations to striatal dopamine signaling that contribute to pathophysiology in HD mouse models, and how these findings relate to human HD studies. We will also discuss current and potential therapeutic interventions for HD that target the dopamine system, and future research directions for this field.
The Tail Effect of Some Prepared Cationic Surfactants on Silver Nanoparticle Preparation and Their Surface, Thermodynamic Parameters, and Antimicrobial Activity
Authors: Shaban Samy M. , Aiad Ismail , Yassin Fathi A. , Mosalam Ahmed 
Published: July 2019

AbstractThe surface parameters of some cationic surfactants having different hydrophobic alkyl chains were assessed in aqueous solution using different techniques; surface tension, ultraviolet‐Visible (UV–Vis) spectroscopy, and conductivity measurements. The obtained critical micelle concentration (CMC) for N‐(2‐((3,4‐dimethoxybenzylidene)amino)ethyl)‐N,N‐dimethyloctan‐1‐aminium bromide (DBAO), N‐(2‐((3,4‐dimethoxybenzylidene)amino)ethyl)‐N,N‐dimethyldodectan‐1‐aminium bromide (DBAD), and N‐(2‐((3,4‐dimethoxybenzylidene)amino)ethyl)‐N,N‐dimethylhexadectan‐1‐aminium bromide (DBAH) in aqueous solution using three techniques are nearly the same. Increasing the hydrophobic chain length enhances micelle formation. Raising the solution temperature from 25 to 65 °C also shows the same trend. The thermodynamic calculations outlined the adsorption propensity of the surfactants at the surface compared to their affinity to form micelles. Both micellization and adsorption processes are enhanced with both the hydrocarbon elongation and with raising the solution temperature. The effect of the surfactant tail on the preparation process of the silver nanoparticles (AgNP) was assessed and confirmed using transmission electron microscope (TEM), dynamic light scattering (DLS), and UV–Vis spectra. Increasing the surfactant tail leads to a smaller particle size with a narrow distribution. The stability of the prepared AgNP is enhanced with hydrophobic surfactant tail elongation as proved with increasing the zeta‐potential of the prepared AgNP colloid. The foaming power, interfacial tension, and emulsification stability of the DBAO, DBAD, and DBAH surfactants were determined. The DBAO, DBAD, and DBAH surfactants showed good antimicrobial activities against both bacteria (Gram positive and negative) and fungi, which have been enhanced because of incorporation of AgNP.
Vegetation recovery on neighboring tidal flats forms an Achilles' heel of saltmarsh resilience to sea level rise
Authors: Zhu Zhenchang , van Belzen Jim , Zhu Qin , van de Koppel Johan , Bouma Tjeerd J. 
Published: July 2019

AbstractCoastal wetlands such as saltmarshes are valued as prominent buffering ecosystems to global climate change and sea level rise (SLR), yet their long‐term persistence may also be threatened by these global change stressors. While saltmarshes are increasingly thought to be resilient to SLR owing to high vertical marsh adaptability, their long‐term stability remains uncertain due to our poor understanding of marsh resilience at the marsh‐tidal flat interface, where wave disturbance can progressively shift vegetated marsh toward a bare tidal flat state. Here, we explore how SLR affects vegetation recoverability on tidal flats using cordgrass, a globally common saltmarsh foundation species, as a model plant. Combined field and model results demonstrate that small increases in wave forcing due to raised water depth over tidal flats can dramatically weaken or even block vegetation recovery from eroding marsh edges, through hampering seed persistence. Vegetation recovery on tidal flats next to the marsh edge thus represents an unrecognized Achilles' heel of marsh resilience to SLR, which if ignored may cause underestimation of marsh vulnerability. These findings are highly relevant for a more comprehensive assessment of marsh susceptibility to SLR in systems where seeds play an essential role in revegetation of tidal flats, and highlight the importance of maintaining either a wave‐protected or well‐elevated tidal flat near the marsh edge that allows for quick vegetation recovery for supporting resilient marshes.
Advances in Ex Situ Tissue Optical Clearing
Authors: Matryba Paweł , Kaczmarek Leszek , Gołąb Jakub 
Published: July 2019

AbstractExamination of whole organs with subcellular resolution in health, disease, and during development is necessary to decipher their biological complexity. However, until recently, this has been virtually impossible due to the natural opacity of organ tissue. Recent progress in tissue optical clearing (TOC) has overcome this limitation by turning organs into transparent, light‐permitting specimens. At least 20 original TOC methods have been developed in less than a decade, which were followed by hundreds of attempts that were aimed at their optimization and practical application. The majority of proof‐of‐concept studies have focused on the brain. However, it is apparent that TOC might be equally valuable when applied to peripheral organs or even the whole body. The progress in TOC for peripheral organs is delineated in an organ‐by‐organ fashion and whole‐body clearing approaches are discussed. Additionally, physical and optical approaches for TOC affecting the optical properties of the samples and image quality are discussed to explore their advantages, limitations, and future possibilities.
MR signal changes in superparamagnetic iron oxide nanoparticle‐labeled macrophages in response to X irradiation
Authors: Yamaguchi Masayuki , Ohnuki Kazunobu , Hotta Kenji , Fujii Hirofumi 
Published: July 2019

To investigate whether MR signals associated with macrophages labeled with superparamagnetic iron oxide nanoparticles (SPIONs) change in response to X irradiation, we performed in vitro MRI of SPION‐labeled macrophage‐like J774A.1 cells that were subsequently X irradiated. We labeled the cells with ferucarbotran at a concentration of 10 μg iron/mL in culture medium for 16 h and subsequently performed X irradiation at doses of 0, 2, 10, or 20 Gy using a low‐energy X‐ray unit. On Days 3 and 6, we suspended the cells in agar at a concentration of 2 × 106 cells/mL and acquired multi‐gradient echo and multi‐spin echo images of the cell samples using a 3 T scanner to estimate R2* and R2. In addition, we microscopically investigated the relationship among the MR signal changes, intracellular SPIONs, and acidic organelles. Our data showed that X irradiation of labeled cells caused increased SPION deposition in lysosomes compared with the non‐irradiated control. On Day 3, R2* and R2 values in the 0 to 10 Gy irradiated samples were dose‐dependently increased 5.4‐ and 1.5‐fold compared with 17 ± 2 and 13 ± 1/s, respectively, in the non‐irradiated control; these values plateaued at more than 10 Gy. Although the increases in R2*, R2, and SPION deposition were still observed in the 10 and 20 Gy samples on Days 6 and 7, the 2 Gy samples showed recovery in these parameters as cell growth was restored. Acidic organelles were temporarily increased in the irradiated cells, which suggests that the reduction in lysosomal acidity was not attributable to SPION deposition. In conclusion, X irradiation of macrophages can cause SPION deposition and R2* and R2 elevation in a specific dose range. MRI of SPION‐labeled and subsequently X‐irradiated macrophages may be utilized as a novel technique for investigating macrophage responses to X irradiation.
Stabilized finite elements for time‐harmonic waves in incompressible and nearly incompressible elastic solids
Authors: Barbone Paul E. , Nazari Navid , Harari Isaac 
Published: July 2019

SummaryThe propagation of waves in elastic solids at or near the incompressible limit is of interest in many current and emerging applications. Standard low‐order Galerkin finite element discretization struggles with both incompressibility and wave dispersion. Galerkin least squares stabilization is known to improve computational performance of each of these ingredients separately. A novel approach of combined pressure‐curl stabilization is presented, facilitating the use of continuous, equal‐order interpolation of displacements and pressure. The pressure stabilization parameter is determined by stability considerations, while the curl stabilization parameter is determined by dispersion considerations. The proposed pressure‐curl–stabilized scheme provides stable and accurate results on a variety of numerical tests for incompressible and nearly incompressible elastic waves computed with linear elements.
Infants from the Tarapacá 40 cemetery (Northern Chile, Formative Period, 1000 BC–AD 600)
Authors: González‐Ramírez Andrea , Pacheco Miranda Aryel , Sáez Arturo , Arregui Wunderlich Iván 
Published: July 2019

AbstractThis study explores the age at death structure, skeletal lesions, and artificial cranial modification (ACM) on 35 nonadults until their 38 months of life recovered from the Tarapacá 40 cemetery, Northern Chile. Age estimations were based primarily on long bones dimensions, whereas skeletal lesions and ACM were recognized on dry bones and in mummified and bundled bodies. Measurements and observations in these later were performed by radiographies. Results show a distribution of ages at death clustered in three groups: around birth and second month of life, between 9 and 12 months of life, and between 18 and 26 months of life. The presence of physiological disruption indicators such as porotic hyperostosis, cribra orbitalia, criba femoris, periostitis and Harris lines, and ACM is described. Then, we discussed the observed age at death structure and the skeletal lesions as reflecting weaning process, and the links between the nature and timing of this practice with social organization of care labour, control over female sexuality, and socio‐economic transformations occurring during the Formative Period in Northern Chile.
Characterization and modeling of reverse‐bias breakdown in Cu(In,Ga)Se2 photovoltaic devices
Authors: Guthrey Harvey , Nardone Marco , Johnston Steve , Liu Jun , Norman Andrew , Moseley John , Al‐Jassim Mowafak 
Published: July 2019

AbstractPartial shading of series‐connected thin‐film photovoltaic modules can force shaded cells into reverse bias, which can cause rapid and irreversible power loss and reduce the practical module lifespan. Unfortunately, this is a common occurrence in field‐deployed modules due to the myriad of environmental factors that can result in partial shading. In this work, we identify as‐grown nonuniformities in the Cu(In,Ga)Se2 (CIGS) absorber layers as the points of origin for the damage induced under reverse‐bias conditions. The structure and chemistry associated with inclusions and voids in the CIGS films cause these features to act as resistive heating elements in reverse‐bias conditions. This localized resistive heating provides the energy required to induce thermal runaway breakdown in the CIGS devices, resulting in damage to charge collection and reduced active area of a device. This mechanism is also described with a robust device model to connect the experimental observations with their physical origins.
Characterizing the inhibition of α‐synuclein oligomerization by a pharmacological chaperone that prevents prion formation by the protein PrP
Authors: Dong Chunhua , Garen Craig R. , Mercier Pascal , Petersen Nils O. , Woodside Michael T. 
Published: July 2019

AbstractAggregation of the disordered protein α‐synuclein into amyloid fibrils is a central feature of synucleinopathies, neurodegenerative disorders that include Parkinson's disease. Small, pre‐fibrillar oligomers of misfolded α‐synuclein are thought to be the key toxic entities, and α‐synuclein misfolding can propagate in a prion‐like way. We explored whether a compound with anti‐prion activity that can bind to unfolded parts of the protein PrP, the cyclic tetrapyrrole Fe‐TMPyP, was also active against α‐synuclein aggregation. Observing the initial stages of aggregation via fluorescence cross‐correlation spectroscopy, we found that Fe‐TMPyP inhibited small oligomer formation in a dose‐dependent manner. Fe‐TMPyP also inhibited the formation of mature amyloid fibrils in vitro, as detected by thioflavin T fluorescence. Isothermal titration calorimetry indicated Fe‐TMPyP bound to monomeric α‐synuclein with a stoichiometry of 2, and two‐dimensional heteronuclear single quantum coherence NMR spectra revealed significant interactions between Fe‐TMPyP and the C‐terminus of the protein. These results suggest commonalities among aggregation mechanisms for α‐synuclein and the prion protein may exist that can be exploited as therapeutic targets.
Crystal structure of the N domain of Lon protease from Mycobacterium avium complex
Authors: Chen Xiaoyan , Zhang Shijun , Bi Fangkai , Guo Chenyun , Feng Liubin , Wang Huilin , Yao Hongwei , Lin Donghai 
Published: July 2019

AbstractLon protease is evolutionarily conserved in prokaryotes and eukaryotic organelles. The primary function of Lon is to selectively degrade abnormal and certain regulatory proteins to maintain the homeostasis in vivo. Lon mainly consists of three functional domains and the N‐terminal domain is required for the substrate selection and recognition. However, the precise contribution of the N‐terminal domain remains elusive. Here, we determined the crystal structure of the N‐terminal 192‐residue construct of Lon protease from Mycobacterium avium complex at 2.4 å resolution，and measured NMR‐relaxation parameters of backbones. This structure consists of two subdomains, the β‐strand rich N‐terminal subdomain and the five‐helix bundle of C‐terminal subdomain, connected by a flexible linker，and is similar to the overall structure of the N domain of Escherichia coli Lon even though their sequence identity is only 26%. The obtained NMR‐relaxation parameters reveal two stabilized loops involved in the structural packing of the compact N domain and a turn structure formation. The performed homology comparison suggests that structural and sequence variations in the N domain may be closely related to the substrate selectivity of Lon variants. Our results provide the structure and dynamics characterization of a new Lon N domain, and will help to define the precise contribution of the Lon N‐terminal domain to the substrate recognition.
An improved femtosecond laser‐ablation fluorination method for measurements of sulfur isotopic anomalies (∆33S and ∆36S) in sulfides with high precision
Authors: Velivetskaya Tatiana A. , Ignatiev Alexander V. , Yakovenko Victoria V. , Vysotskiy Sergey V. 
Published: July 2019

RationaleMeasurements of the multiple sulfur isotopic composition (δ34S, δ33S and δ36S values) of ancient sedimentary sulfide are useful for clarifying and reconstructing the picture of the global sulfur cycle on the early Earth. The methods used for these measurements should provide a high level of precision for the determination of sulfur isotope mass‐independent anomalies (∆33S and ∆36S values). Here we propose some improvements to the earlier published femtosecond laser‐ablation fluorination method to make it suitable for measuring both ∆33S and ∆36S values in the Archean sedimentary sulfides with acceptable precision.MethodsA new gas purification system for the laser‐ablation fluorination method has been developed. The design of this system is based on temperature‐controlled flow traps for cryogenic separation of SF6 gas from other fluorinated products produced by fluorination of sulfide minerals. Compared with the previous version of the purification system, the efficiency of SF6 purification was significantly improved, which in turn improved the precision of the method for in situ GC/IRMS measurements of 36S/32S ratios (and determination of ∆36S values).ResultsThe improved method was tested using IAEA reference materials, as well as samples of natural pyrite with zero and non‐zero sulfur isotope anomalies. For samples of ~12–13 nmol SF6 (optimal size), the overall precision of the method is ±0.03‰ for ∆33S values and ±0.27‰ for ∆36S values. This level of precision is satisfactory to examine the sulfur isotope anomalies in the rock.ConclusionsThe improved femtosecond laser‐ablation fluorination method is applicable for in situ measurements of δ34S, ∆33S and ∆36S values in sulfide minerals.
The colors of heath flowering – quantifying spatial patterns of phenology in Calluna life‐cycle phases using high‐resolution drone imagery
Authors: Neumann Carsten , Behling Robert , Schindhelm Anne , Itzerott Sibylle , Weiss Gabriele , Wichmann Matthias , Müller Jörg 
Published: July 2019

AbstractRecent developments in high‐resolution ecosystem mapping using unmanned aerial vehicles (UAV) open up promising perspectives for the monitoring of fine‐scale vegetation patterns and ecological functioning. In this study, we examine the potential of UAV imagery to track the structural composition and related phenological traits of the dwarf shrub Calluna vulgaris on a former military training area. On a European Natura 2000 heathland site, habitat management is shown to be evaluated on the basis of flowering dynamics and reproductive recovery as a proxy of functional changes that are generated after fire destruction. In particular, we utilize true color camera information and digital surface models to determine the spatiotemporal evolution of Calluna life‐cycle phases and flowering phenology 2 years after controlled burning. A stepwise methodological framework is presented that extracts Calluna pixels, spatially separates juvenile and mature life‐cycle phases, differentiates between generative and vegetative shoot extension and finally quantifies proportions of flowers, fruits and vegetative growth in two consecutive peak flowering periods. We show that Calluna life‐cycle phases can be spatially differentiated in pioneer, building and mature phases in UAV imagery. In the juvenile phase, regeneration from germination is low (<10%) and sprouting from the stem base dominates recovery patterns after fire management. The study further reveals that the distribution of flowering and fruiting during peak flowering time is spatially heterogeneous with high variations between years. In the fire unaffected mature phase, proportions of flowers and fruits are reduced indicating a decrease in reproductive capacity of unmanaged Calluna stands. A phenological phase shift is detected from flowering to fruiting that is related to an increase of Calluna growth height. The study shows that the functional patterns of growth and reproduction can be mapped for heathland ecosystems using simple true color drone cameras.
New Cyclodepsipeptide Derivatives Revealed by Genome Mining and Molecular Networking
Authors: Paulo Bruno S. , Sigrist Renata , Angolini Célio F. F. , De Oliveira Luciana G. 
Published: July 2019

AbstractGenome mining and molecular networking analyses have revealed a renewed capacity to uncover molecules and biosynthetic pathways from bacterial secondary metabolism. The present study describes the association of genome mining and molecular networking to correlate production of valinomycin cyclodepsipeptide derivatives by Streptomyces sp. CBMAI 2042. Additionally, expression of the entire gene cluster in a heterologous host successfully allowed the association of this biosynthetic assembly to the production of montanastatin, valinomycin and at least five structural analogues, revealing a plasticity of the modules and an interesting thioesterase activity capable of assembling two or three units of the tetradepsipeptide monomer.
Highly Active Ternary Nickel–Iron oxide as Bifunctional Catalyst for Electrochemical Water Splitting
Authors: Dalai Namita , Mohanty Bishnupad , Mitra Arijit , Jena Bijayalaxmi 
Published: July 2019

AbstractThe development of noble metal free, robust catalyst is highly sought for commercialization of clean, renewable energy technology and to replace the fossil fuel‐based energy equipments. Herein, we report a highly efficient and stable ternary Nickel Iron oxide (NiFe2O4) electrocatalyst for bifunctional oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline medium. The as‐synthesized NiFe2O4 has been confirmed by techniques like FESEM, HR‐TEM, powder X‐ray diffraction (XRD), and X‐ray photoelectron spectra analysis. NiFe2O4 demonstrate nanoparticle morphology with an average size of ∼10 nm. The synthesized NiFe2O4 electrocatalyst exhibit superior electrocatalytic efficiency for OER, and achieves a current density of 10 mA cm−2 at an overpotential of 290 mV, with smaller Tafel slope of 42 mV/dec. A stable performance of OER is obtained at 10 mA cm−2 for more than 8 h. The electrocatalytic activity of NiFe2O4 is comparable with benchmark electrocatalyst IrO2/C. Similarly, NiFe2O4 also shows superior HER activity in 1 M KOH. The enhanced bi‐functional activity of NiFe2O4 is thought to be the synergy between the multicomponent structure of NiFe2O4, high surface area, and stability leading to high electrical conductivity.