bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long‐Term Colloidally Stable Aqueous Dispersions of ≤5 nm Spinel Ferrite Nanoparticles
Authors: Eckardt Mirco , Thomä Sabrina L. J. , Dulle Martin , Hörner Gerald , Weber Birgit , Förster Stefan , Zobel Mirijam 
Published: November 2020

AbstractApplications in biomedicine and ferrofluids, for instance, require long‐term colloidally stable, concentrated aqueous dispersions of magnetic, biocompatible nanoparticles. Iron oxide and related spinel ferrite nanoparticles stabilized with organic molecules allow fine‐tuning of magnetic properties via cation substitution and water‐dispersibility. Here, we synthesize≤5 nm iron oxide and spinel ferrite nanoparticles, capped with citrate, betaine and phosphocholine, in a one‐pot strategy. We present a robust approach combining elemental (CHN) and thermal gravimetric analysis (TGA) to quantify the ratio of residual solvent molecules and organic stabilizers on the particle surface, being of particular accuracy for ligands with heteroatoms compared to the solvent. SAXS experiments demonstrate the long‐term colloidal stability of our aqueous iron oxide and spinel ferrite nanoparticle dispersions for at least 3 months. By the use of SAXS we approved directly the colloidal stability of the nanoparticle dispersions for high concentrations up to 100 g L−1.
Warranty assessment of photovoltaic modules based on a degradation probabilistic model
Authors: Prieto‐Castrillo Francisco , Núñez Neftalí , Vázquez Manuel 
Published: November 2020

AbstractEvaluating the probability of failure of a product during the warranty is key to estimating the cost of its entire life cycle. Photovoltaic (PV) modules are the most reliable elements of a PV system, and their high reliability translates into long warranty periods (typically 25 to 30 years). The number of PV modules that fail during warranty and when they failed is an important issue to estimate the life cycle cost of PV modules. In this paper, we propose a coupled degradation‐warranty model for PV modules. The proposed model is aimed to assess the probability of failure over time covered by warranty based on degradation data. This allows us to estimate the time of PV modules failure covered by the warranty. Although the warranty model has been applied to some forms of degradation and sales functions, our method can be applied to any real application. This allows the key parameters of the warranty to be obtained in a simple way. The required degradation parameters to fulfill warranty depend on the allowable ratio of warranted elements. However, the main conclusion of the influence of degradation rates on warranty is that it is not possible to fulfill 25 years of warranty if degradation rates are larger than 0.8%/year. The required degradation rates values, for 25 years of warranty, will be lower than 0.5%/year if the allowed warranted element is in the range of 1%.
Comparative degradation analysis of different photovoltaic technologies on experimentally simulated water bodies and estimation of evaporation loss reduction
Authors: Kumar Manish , Kumar Arun , Gupta Rajesh 
Published: November 2020

AbstractDegradation of photovoltaic (PV) systems on water bodies can be matter of serious concern due to high humid environmental conditions above water surface as compared with land surface. The primary objective of this study is to assess the reliability of various PV technologies for megawatt‐scale installations by analyzing their degradation on water bodies. An experimental study has been performed for 13 months on three commercially available PV technologies, namely, multicrystalline‐Si (m‐Si), heterojunction intrinsic thin layer (HIT), and cadmium telluride (CdTe). Degradation of these PV technologies on water and comparison of their degradation with respective land‐mounted PV technologies have been presented. Various approaches have been implemented for degradation analysis. The degradation in electrical parameters of all PV modules has been measured. Also, a mathematical PV model has been developed to analyze the internal parameters degradation in different PV technologies. Moreover, thermal imaging has been conducted to distinguish various defects in all PV modules. Evaporation reduction is a significant aspect of water‐mounted PV systems, and thus, analytical model to estimate evaporation has been developed and experimentally validated in this study. The HIT PV technology is observed to be degrading almost at the same rate of about 0.50% on both water and land surfaces, whereas degradation of water‐mounted m‐Si module has been found 1.32% which is significantly higher than the corresponding land‐mounted module which has degradation of 0.93%. Degradation in CdTe modules is 1.68% on water, which is marginally higher than corresponding land‐based module that has degradation of 1.41%.
Increasing joint attention and social play through peer‐mediated intervention: A single case design
Authors: Krier Jessie , Lambros Katina M. 
Published: November 2020

AbstractThis study evaluated the effectiveness of a peer‐mediated intervention on joint attention (JA) and social play skills for students with autism spectrum disorder (ASD) using a multiple baseline design. Peer‐mediated interventions are an evidence‐based practice, but there is limited research on using peers outside of the target student's classroom and using them with severely impacted students. In this study, the research team trained third‐grade peers to work with preschoolers with ASD in one‐on‐one play sessions. JA, parallel play, and common focus play were increased during intervention, while solitary and unoccupied play were decreased. Social validity was high as reported by participants. This study provides promising data for increased inclusion of severely impacted students, with benefits for all students involved.
Is there a future for the use of left ventricular assist devices in Duchenne muscular dystrophy?
Authors: Hayes Emily A. , Nandi Deipanjan 
Published: November 2020

AbstractDuchenne muscular dystrophy (DMD) is the most common form of childhood muscular dystrophy resulting in progressive muscle wasting and weakness. With advancements in respiratory care and the use of glucocorticoids, cardiomyopathy has surpassed respiratory compromise as the leading cause of morbidity and mortality in this patient population. As muscular dystrophy remains a relative contraindication to heart transplantation, end‐stage heart failure management represents a major therapeutic challenge. Long‐term left ventricular assist device (LVAD) therapy has emerged as a promising management strategy to improve the survival and quality of life in DMD cardiomyopathy. Preoperative planning, optimal patient selection, aggressive postoperative rehabilitation, and continued discussion of goals of care are critical considerations for the appropriate use of LVAD in DMD patients with cardiomyopathy.
Predicting cryptic ligand binding sites based on normal modes guided conformational sampling
Authors: Zheng Wenjun 
Published: November 2020

AbstractTo greatly expand the druggable genome, fast and accurate predictions of cryptic sites for small molecules binding in target proteins are in high demand. In this study, we have developed a fast and simple conformational sampling scheme guided by normal modes solved from the coarse‐grained elastic models followed by atomistic backbone refinement and side‐chain repacking. Despite the observations of complex and diverse conformational changes associated with ligand binding, we found that simply sampling along each of the lowest 30 modes is near optimal for adequately restructuring cryptic sites so they can be detected by existing pocket finding programs like fpocket and concavity. We further trained machine‐learning protocols to optimize the combination of the sampling‐enhanced pocket scores with other dynamic and conservation scores, which only slightly improved the performance. As assessed based on a training set of 84 known cryptic sites and a test set of 14 proteins, our method achieved high accuracy of prediction (with area under the receiver operating characteristic curve >0.8) comparable to the CryptoSite server. Compared with CryptoSite and other methods based on extensive molecular dynamics simulation, our method is much faster (1‐2 hours for an average‐size protein) and simpler (using only pocket scores), so it is suitable for high‐throughput processing of large datasets of protein structures at the genome scale.
Generalized unitary coupled cluster excitations for multireference molecular states optimized by the variational quantum eigensolver
Authors: Greene‐Diniz Gabriel , Muñoz Ramo David 
Published: November 2020

AbstractThe variational quantum eigensolver (VQE) algorithm, designed to calculate the energy of molecular ground states on near‐term quantum computers, requires specification of symmetries that describe the system, for example, spin state and number of electrons. This opens the possibility of using VQE to obtain excited states as the lowest‐energy solutions of a given set of symmetries. In this paper, the performances of various unitary coupled cluster (UCC) ansätze applied to VQE calculations on excited states are investigated using quantum circuits designed to represent single reference and multireference wavefunctions to calculate energy curves with respect to variations in the molecular geometry. These ansätze include standard Unitary Coupled Cluster Singles and Doubles (UCCSD), as well as modified versions of Unitary Coupled Cluster Generalized Singles and Doubles (UCCGSD) and k‐UpCCGSD, which are engineered to tackle excited states without undesired spin symmetry crossover to lower states during VQE optimization. These studies are carried out on a range of systems, including H2, H3, H4, NH, OH+, CH2, and , covering examples of spin singlet, doublet, and triplet molecular ground states with single and multireference excited states. In most cases, our calculations are in excellent agreement with results from full‐configuration interaction calculations on classical machines, thus showing that the VQE algorithm is capable of calculating the lowest excited state at a certain symmetry, including multireference closed‐ and open‐shell states, by setting appropriate restrictions on the excitations considered in the cluster operator and appropriate constraints in the qubit register encoding the starting mean field state.
Ecosystem dynamics of crop–pasture rotations in a fifty‐year field experiment in southern South America: Century model and field results
Authors: Baethgen Walter E. , Parton William J. , Rubio Valentina , Kelly Robin H. , M. Lutz Susan 
Published: November 2020

AbstractThe Century model was used to simulate soil C and N cycling and crop production dynamics in an ongoing field experiment in Uruguay (started in 1963). The model was calibrated using observed data from three treatments (crop or crop–pasture rotations) and validated with a fourth treatment. The model correctly predicted the impact of different treatments on microbial biomass, N mineralization, soil respiration, and crop yields. The model and observed data show that soil respiration, N mineralization, soil C, and crop yields increase with increasing plant‐derived C inputs caused by increasing the frequency of pastures in the rotations. This is one of the first papers that show the strong positive correlation of observed soil C with plant C soil inputs to field‐observed microbial biomass, soil respiration, and N mineralization. The results also showed that reducing tillage and transitioning to a no‐till system increased soil C and reduced soil erosion. The main path of soil C losses was heterotrophic microbial respiration, which accounted for 66% of the total C lost in a continuous crop rotation and no fertilizers, 71% in a continuous crop rotation with fertilizers, and 86% in a crop–pasture rotation with fertilizers. Model results from a degraded cropping system showed that adding grass–clover (Trifoliumspp.) pastures greatly increased plant production and soil C, whereas reducing the frequency of grass–clover pastures in high‐fertility cropping systems from 50% of the time to 25% reduces crop yields and soil C. Including cover crops substantially increases crop production and maintains soil C in high‐fertility and degraded cropping systems.
Design and Development of Cholinesterase Dual Inhibitors towards Alzheimer's Disease Treatment: A Focus on Recent Contributions from Computational and Theoretical Perspective
Authors: Adeowo Fatima Y. , Lawal Monsurat M. , Kumalo Hezekiel M. 
Published: November 2020

AbstractIn recent times, review topics on Alzheimer's disease (AD) have received massive attention, especially on drug design and development of potent inhibitors targeting specific pathway(s) of this multifaceted disease. Drug design and development through the use of computer has taken an intriguing dimension over the last two decades, and AD drug design is not an exception. Computational approaches have found usage in identifying potentially active molecules targeting specific enzyme or gene in the pathological pathway of a disease such as AD. Herein, we present an overview of research contributions over the last ten years from different authors who had used computational approaches to explore potent dual inhibitors of the cholinesterase enzymes linked with AD pathogenesis. We gave an introductory background of the disease, highlight challenges of in silico approach to drug design, and discuss its pros and cons. The overview also covers previously reported review works which are related to the topic. We proposed that continued research efforts to unravel more effective dual acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors through computational tools could plausibly be a successful approach to AD cure. Computational researchers should leverage on the available cost‐effective resources to identify lead compounds and work in collaboration with experimental personnel to push their discovery forward.
Development of Mango Peel Derived Activated Carbon‐Nickel Nanocomposite as an Adsorbent towards Removal of Heavy Metal and Organic Dye Removal from Aqueous Solution
Authors: Bose Saswata , Ghosh Anirban , Das Arit , Rahaman Mehabub 
Published: November 2020

AbstractIn this study activated carbon has been prepared using waste mango fruit peels as the precursor in a facile manner (MAC). In order to increase the efficiency and regenerability of activated carbon, nickel nanoparticles were impregnated. Morphological and crystalline structures of the prepared composite were investigated by field emission scanning electron microscopy (FESEM) and X‐ray diffraction (XRD) analysis. MAC/Ni as an adsorbent was found to remove 98 % and 93 % of Rhodamine B (RhB) dye and manganese ions (Mn2+) from their aqueous solutions. The regeneration study demonstrated that after the completion of five adsorption cycles, the removal efficiency for RhB and Mn2+ was 88.7 % and 85.2 %, respectively, corroborating the reusability of the prepared adsorbent. The kinetics of the adsorption of RhB and Mn2+ ions on the surface of nanocomposite was found to follow the pseudo‐second order model with a great degree of accuracy (R2∼0.99). The value of the equilibrium parameter RL was found to be 0.015 and 0.003 respectively for RhB and Mn2+ at 303 K which suggested that the Langmuir isotherm could be used to describe the favorable adsorption of the RhB dye and Mn2+ ions on the adsorbent under the conditions used in the study.
Neptunium(V) Complexes with Lipophilic N‐Donor Extractant Ligands
Authors: Andreev Grigory , Budantseva Nina 
Published: November 2020

AbstractNeptunium(V) complexes with N‐donor lipophilic extractants, 2,2′:6′,2′′‐terpyridine (Terpy), 2,4,6‐tri‐2‐pyridyl‐1,3,5‐triazine (TPTZ), and 6,6’‐bis(5,6‐diethyl‐1,2,4‐triazin‐3‐yl)‐2,2’bipyridine (C2‐BTBP), have been synthesized and characterized by X‐ray crystallography as well as vis‐NIR and IR spectroscopy. The structures display coordination of one N‐donor ligand to the NpO2+group. In all cases, the Np atom is found in a pentagonal bipyramidal coordination environment. The structures exhibit 0D topologies, except the neptunium formate complex with terpyridine, where the anion acts as a bridging ligand and forms an infinite chain structure. The complex with C2‐BTBP is the first example of a structurally characterized Np complex with this ligand. Vis‐NIR and IR spectra of the compounds correlate with their crystal structures.
Analysis of the Stable Interphase Responsible for the Excellent Electrochemical Performance of Graphite Electrodes in Sodium‐Ion Batteries
Authors: Wang Zhaohua , Yang Haoyi , Liu Yiran , Bai Ying , Chen Guanghai , Li Ying , Wang Xinran , Xu Huajie , Wu Chuan , Lu Jun 
Published: November 2020

AbstractConsiderable efforts have been exerted to understand the formation and properties of the solid electrolyte interphase (SEI) in sodium ion batteries. However, the puzzling existence and role of SEI behind the huge volume changes of the graphite electrodes need to be answered. Herein, the reason of how ether‐derived SEI maintains excellent reversibility despite the huge volume changes during cycling is unraveled. Theoretical simulations and Fourier‐transform infrared spectroscopy demonstrate the formation mechanism of an SEI between the graphite anode and electrolyte. Furthermore, the high mechanical tolerance of the ether‐derived SEI is confirmed in atomic force microscopy. A depth profile of X‐ray photoelectron spectroscopy points to a multilayer structure of the ether‐derived SEI. The outer layer comprises organics (sodium alkoxide), while the inorganics (Na2CO3, NaF) in interior region are mixed with some organics. Notably, the presence of organics ensures the adaptability of the SEI to the volume expansion of graphite during cycling, and the concentrated distribution of inorganics improves the Young's modulus (resistance to deformation). Therefore, the graphite anode exhibits high cycle stability (96.6% capacity retention ratio at 1 A g–1 over 860 cycles) and efficiency (≈99.5%).
Beaver: Nature's ecosystem engineers
Authors: Brazier Richard E. , Puttock Alan , Graham Hugh A. , Auster Roger E. , Davies Kye H. , Brown Chryssa M. L. 
Published: November 2020

AbstractBeavers have the ability to modify ecosystems profoundly to meet their ecological needs, with significant associated hydrological, geomorphological, ecological, and societal impacts. To bring together understanding of the role that beavers may play in the management of water resources, freshwater, and terrestrial ecosystems, this article reviews the state‐of‐the‐art scientific understanding of the beaver as the quintessential ecosystem engineer. This review has a European focus but examines key research considering both Castor fiber—the Eurasian beaver and Castor canadensis—its North American counterpart. In recent decades species reintroductions across Europe, concurrent with natural expansion of refugia populations has led to the return of C. fiber to much of its European range with recent reviews estimating that the C. fiber population in Europe numbers over 1.5 million individuals. As such, there is an increasing need for understanding of the impacts of beaver in intensively populated and managed, contemporary European landscapes. This review summarizes how beaver impact: (a) ecosystem structure and geomorphology, (b) hydrology and water resources, (c) water quality, (d) freshwater ecology, and (e) humans and society. It concludes by examining future considerations that may need to be resolved as beavers further expand in the northern hemisphere with an emphasis upon the ecosystem services that they can provide and the associated management that will be necessary to maximize the benefits and minimize conflicts.This article is categorized under:
Water and Life > Nature of Freshwater Ecosystems
Panel Analysis of the Relationship Between Weather Variability and Sectoral Output in Kenya
Authors: Mulama Olga Nekesa , Kariuki Caroline Wanjiru 
Published: November 2020

AbstractClimate change and economic growth are closely connected. Climate change has the potential to reduce economic growth in developing countries due to their limited ability to respond to the negative impacts of a changing climate. A better understanding of weather variability can enhance climate change policies, which would help to support economic growth in these countries. As such, this research sought to examine if there is a long-run relationship between sectoral output and weather variables (temperature and rainfall) and to analyze the effect of weather variability on sectoral output using a panel of 13 sectors in Kenya.A Pedroni cointegration test was carried out to find out if there exists a long-run relationship among the variables and thereafter, a fully modified ordinary least squares regression was conducted to establish the effect of weather variability on sectoral output. The results indicate that there is a long-run relationship between temperature and sectoral output. Moreover, temperature has a larger effect on sectoral output compared to rainfall. With the evidence gathered from this research, it can be concluded that weather variability has an economic effect on sectoral output in Kenya. Given this, the Kenyan government needs to take a keen interest in understanding the effect of weather variability on the economy and in the broader picture, take steps to mitigate climate change.
Scattering equations in AdS: scalar correlators in arbitrary dimensions
Authors: Eberhardt Lorenz , Komatsu Shota , Mizera Sebastian 
Published: November 2020

AbstractWe introduce a bosonic ambitwistor string theory in AdS space. Even though the theory is anomalous at the quantum level, one can nevertheless use it in the classical limit to derive a novel formula for correlation functions of boundary CFT operators in arbitrary space-time dimensions. The resulting construction can be treated as a natural extension of the CHY formalism for the flat-space S-matrix, as it similarly expresses tree-level amplitudes in AdS as integrals over the moduli space of Riemann spheres with punctures. These integrals localize on an operator-valued version of scattering equations, which we derive directly from the ambitwistor string action on a coset manifold. As a testing ground for this formalism we focus on the simplest case of ambitwistor string coupled to two cur- rent algebras, which gives bi-adjoint scalar correlators in AdS. In order to evaluate them directly, we make use of a series of contour deformations on the moduli space of punctured Riemann spheres and check that the result agrees with tree level Witten diagram computations to all multiplicity. We also initiate the study of eigenfunctions of scattering equations in AdS, which interpolate between conformal partial waves in different OPE channels, and point out a connection to an elliptic deformation of the Calogero-Sutherland model.