bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding arid‐region waterbird community dynamics during lake dry‐downs
Authors: Cumming Graeme S. , Henry Dominic A. W. , Mutumi Gregory L. , Ndlovu Mduduzi 
Published: August 2021

AbstractThe community dynamics of organisms that exhibit multi‐scale responses to habitat change are poorly understood. We quantified changes in species diversity and the functional composition of a waterbird community over two iterations of a repeated transition, the annual drying‐down of arid‐region Lake Ngami, Botswana. We used our data to test three theoretical predictions: simplification of the bird community over time due to a reduction in habitat area and concurrent niche loss; large fluctuations in densities of mobile, opportunistic species; and high variance in predator and prey abundance. Despite temporal variance in species accumulation, we observed no obvious simplification and distinct but consistent groupings of abundance and composition across transitional stages. There were some rapid shifts in functional composition, such as loss of deepwater foragers; winners and losers also occurred within foraging guilds. We conclude that understanding community‐level trends during transitional periods will require stronger theoretical frameworks that more effectively integrate unique species traits and functional groups. For conservation managers, our study offers a cautionary tale of the importance of understanding connectivity, trajectories of change, and the potential for large fluctuations in animal communities independent of management actions during periods of ecological transition.
The impact of lateral flow contraction on the rock plucking process under sub‐critical flow conditions
Authors: Saha Rupayan , Lee Jun Seon , Hong Seung Ho 
Published: August 2021

AbstractRock plucking is the vertical removal of chunks of rock along intersection joint planes by flowing water. The plucking of durable jointed rock in a natural stream alters stream morphology and potentially damages a bridge substructure situated on a rock foundation by local erosion. Despite its importance, the mechanics of bedrock erosion by plucking are not well understood. In this study, we conduct laboratory experiments to investigate the threshold of block entrainment through plucking near a flow obstruction under sub‐critical conditions. In a laboratory flume, we reproduce a wide range of typical lateral flow contraction scenarios that occur around a large rock or bridge substructure and investigate the process of the vertical entrainment of blocks near the obstruction. Two different modes of block removal process (impulsive plucking and accumulative plucking) are observed near the bluff structure. We find that under severe flow contraction, blocks are more likely to escape quickly via impulsive plucking because higher flow contraction and the resulting strong local turbulence around the structure generate large instantaneous uplift force that removes the block within a short period of time; however, we observe accumulative plucking under weaker flow contraction near the bluff structure. From the experimental results, we develop a formula for the threshold point of block dislocation caused by plucking with respect to the degree of lateral flow contraction. The results indicate that increasing the flow contraction ratio reduces block stability because of higher flow acceleration and the increased turbulence effect near the upstream edge of the obstruction. The results of this study should be useful to those who estimate the rate of rock erosion by plucking in natural open channels around a bluff structure.
Deactivation behaviour of intermetallic Ga‐Ni catalyst in CO2 hydrogenation to methanol
Authors: Ahmad Kaisar , Anushree  , Upadhyayula Sreedevi 
Published: August 2021

AbstractThe chemical conversion of greenhouse gas CO2 to environmentally benign compounds, especially alternative fuels like methanol, is an inevitable solution to the global warming problem. The intermetallic catalysts exhibit superior catalytic activity compared to the monometallic ones but suffer from loss of activity during the reaction. Herein, we report the influence of the preparation method on the deactivation behaviour of Ga3Ni5 catalyst in CO2 hydrogenation to methanol. The Ga3Ni5 catalyst was prepared through three different methods. The spent catalysts from the reactor were characterized by X‐ray diffraction, transmission electron microscopy‐energy dispersive X‐ray spectroscopy (TEM‐EDX), Brunaue‐Emmett‐Teller (BET), H2‐pulse chemisorption, and Fourier‐transform infrared spectroscopy (FTIR) technique to evaluate the cause and nature of deactivation. After 250 hr of CO2 hydrogenation, all catalysts had lost about 50% of their initial activity due to the erosion of active sites. The nanoparticle dispersion was found to increase in the order Ga3Ni5‐CE< Ga3Ni5‐IWI < Ga3Ni5‐CP. The activity of catalysts during methanol synthesis (at 473 K, 20 bar) initially depicted a similar trend. However, the selectivity to methanol remained comparatively high for the catalysts prepared by the co‐precipitation method. The loss of activity in Ga3Ni5 catalysts was mainly attributed to the metal sintering and a lesser extent, by coke deposition. The kinetics of deactivation was studied based on the normalized dispersion, and the deactivation rate constant was estimated using the power‐law kinetic rate model. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.
The Impact of Ionic Surfactants on the Crystallisation of Glycine Polymorphs
Authors: Davey Roger J. , Dowling Richard J. , Cruz‐Cabeza Aurora J. 
Published: August 2021

AbstractThe glycine polymorphs have provided a rich and challenging tapestry for crystal growth and polymorphism studies. In this new contribution we report some preliminary studies of the impact of two ionic surfactants on the morphologies and the competitive crystallisation of the α and γ polymorphs. We find both selective growth inhibition and acceleration combined with fascinating crystal aggregates. The role of both monomeric and micellar forms of the surfactants are explored and discussed in terms of nucleation and crystal growth processes.
Development of a highly stable picosecond time‐resolved Raman spectrometer near Fourier‐transform limit with a femtosecond light source
Authors: Tokita Tsukasa , Takaya Tomohisa , Iwata Koichi 
Published: August 2021

AbstractPicosecond time‐resolved Raman spectroscopy is an experimental method effective for studying the structure and dynamics of short‐lived transient species. Spectral resolution of less than 10 cm−1 and high stability of the laser light source are both critically important for extracting detailed information on the structure and dynamics of the transient species from the observed picosecond time‐resolved Raman spectra. However, it is often technically challenging to obtain stable picosecond pulses that have a spectral width of 10 cm−1 or smaller, which is only achieved if the time‐energy product of a light pulse is close to the Fourier‐transform limit, from a picosecond light source. We present a new scheme for a picosecond time‐resolved Raman spectrometer with a stable femtosecond laser as its light source. Femtosecond light pulses from the laser are successfully converted to stable picosecond light pulses with a volume‐grating notch filter. The spectral and temporal widths of the prepared picosecond pulse are 6.0 cm−1 and 3.2 ps, respectively, close to the Gaussian Fourier‐transform limit. The vibrational cooling dynamics of S1 trans‐stilbene prepared with the photoexcitation at 316 and 266 nm has been observed with the newly developed picosecond time‐resolved Raman spectrometer, demonstrating a high capability of the proposed method.
Characterizing historical transformation trajectories of the forest landscape in Rome's metropolitan area (Italy) for effective planning of sustainability goals
Authors: Solano Francesco , Praticò Salvatore , Piovesan Gianluca , Chiarucci Alessandro , Argentieri Alessio , Modica Giuseppe 
Published: August 2021

AbstractWith the aim at developing a landscape dynamics framework for environmental planning and management and testing the effectiveness of protected areas in achieving the 2030 Agenda of the United Nations sustainability goals, we characterized the historical transformation trajectories of forest area changes from 1936 to 2010 in the Metropolitan City of Rome Capital (Italy). Remote sensing‐based products coupled with landscape pattern metrics and fragmentation analysis have been implemented, comparing different historical forest maps. The results show a remarkable forest area gain – from 17.6% to 25.5% – thanks to 68,299 ha of recently established forest. Statistical descriptors showed that the highest relative gain occurred in mountain zones, confirming a wide European forest recovery pattern in marginal areas from past deforestation and overexploitation. Deforestation mainly occurred in the flat and hilly areas where almost 26,000 ha of forests were lost since 1936. In summary, two main forest landscape dynamics were reconstructed: (I) the increase of forest cover fragmentation in the lowland areas; and (II) the rise in the forest area in the interior sectors of the mountain landscape, mainly within protected areas. Restoring the forest ecosystem's bioecological integrity has been highlighted as an urgent action for biodiversity conservation and carbon mitigation. In lowland areas, the study revealed the urgent need to establish new protected areas and rewilding spaces as landscape metrics are relatively below the sustainability targets for healthy forest ecosystems. The proposed framework can be used for testing the effectiveness of environmental planning and management in other forest landscapes to achieve the Agenda 2030 goals.
MGRNN: Structure Generation of Molecules Based on Graph Recurrent Neural Networks
Authors: Lai Xin , Yang Peisong , Wang Kunfeng , Yang Qingyuan , Yu Duli 
Published: August 2021

AbstractMolecular structure generation is a critical problem for materials science and has attracted growing attention. The problem is challenging since it requires to generate chemically valid molecular structures. Inspired by the recent work in deep generative models, we propose a graph recurrent neural network model for drug molecular structure generation, briefly called MGRNN (Molecular Graph Recurrent Neural Networks). MGRNN combines the advantages of both iterative molecular generation algorithm and the efficiency of the training strategies. Moreover, MGRNN shows: (i) efficient computation for training; (ii) high model robustness for data; and (iii) an iterative sampling process, which allows to use chemical domain expertise for valency checking. Experimental results show that MGRNN is able to generate 69 % chemically valid molecules even without chemical knowledge and 100 % valid molecules with chemical rules.
Three dimensional radial echo planar imaging for functional MRI
Authors: Rettenmeier Christoph A. , Maziero Danilo , Stenger V. Andrew 
Published: August 2021

PurposeTo demonstrate a novel 3D radial echo planar imaging (3D REPI) sequence for flexible, rapid, and motion‐robust sampling in fMRI.MethodsThe 3D REPI method expands on the recently described golden angle rotated EPI trajectory using radial batched internal navigator echoes (TURBINE) approach by exploiting the unused perpendicular direction in the EPI readout to form fast analogues of rotated stack of stars or spirals trajectories that cover all 3 dimensions of k‐space. An iterative conjugate gradient algorithm with SENSE reconstruction and time‐segmented non‐uniform fast Fourier transform (FFT) was used for parallel imaging acceleration and to account for the effects of B0 inhomogeneity. The golden angle rotation allowed for sliding window reconstruction schemes to be applied in brain BOLD fMRI experiments.ResultsCombined whole brain visual and motor fMRI experiments were successfully carried out on a clinical 3T scanner at 2 mm isotropic and 1 × 1 × 2 mm3 resolutions using the 3D REPI design. Improved sampling characteristics and image quality were observed for twisted trajectories at the expense of prolonged readout times and off‐resonance effects. The ability to correct for rigid motion correction was also demonstrated.Conclusions3D REPI presents a flexible approach for segmented volumetric fMRI with motion correction and high in‐plane spatial resolutions. Improved BOLD fMRI brain activation maps were obtained using a sliding window reconstruction.
The Coax Dipole: A fully flexible coaxial cable dipole antenna with flattened current distribution for body imaging at 7 Tesla
Authors: van Leeuwen Carel C. , Steensma Bart R. , Klomp Dennis W. J. , van den Berg Cornelis A. T. , Raaijmakers Alexander J. E. 
Published: August 2021

PurposeThe coax dipole antenna, a flexible antenna for body imaging at 7T is presented. Similar to the high impedance coil, this coaxial cable antenna is fed on the central conductor and through gaps in the shield, the current passes to the outside of the antenna to generate B1 field. This could achieve more favorable current distributions and better adaptation to the body curvature.MethodsFinite difference time domain (FDTD) simulations are performed to optimize the positions of the gaps in the shield for a flat current profile. Lumped inductors are added to each end to reduce losses. The performance of a single antenna is compared to a fractionated dipole using B1 maps and MR thermometry. Finally, an array of eight coax dipoles is evaluated in simulations and used for in‐vivo scanning.ResultsAn optimal configuration is found with gaps located at 10 cm from the center and inductor values of 28 nH. In comparison to the fractionated dipole antenna, in single antenna phantom measurements the coax dipole achieves similar B1 amplitude with 18% lower peak temperature. In simulations, the eight‐channel array of coax dipoles improved B1 homogeneity by 18%, along with small improvements in transmit efficiency and specific absorption rate (SAR). MRI measurements on three volunteers show more consistent performance for the coax dipoles.ConclusionThe coax dipole is a novel antenna design with a flattened current distribution resulting in beneficial properties. Also, the flexible design of the coax dipoles allows better adaptation to the body curvature and can potentially be used for a wide range of imaging targets.
“Power back in the community”: Going beyond performative generosity in nonprofits
Authors: Ojeda Rosie , Wall Maeve 
Published: August 2021

AbstractOur study critiques nonprofits in the United States, using settler colonial and critical whiteness theories. Nonprofits rely on the donations of wealthy white donors to support marginalized communities. Yet, nonprofits, through donor support, fund projects that benefit marginalized communities without critiquing how the money was earned, who it belongs to, and why such inequities exist. If nonprofits seek to truly invest in marginalized communities, they need to be critical of their own model. This article depicts a composite counter‐story about a woman reflecting on her experience working for a nonprofit, and her decision to quit her job when she realizes that the organization she worked for did not truly put “power back in the community” like they claimed. Using a fictionalized counter‐story, this article presents the very real ways in which nonprofits can use Indigenous values to go beyond performative generosity. The five values that emerge from our counter‐story are: relationality, respect, responsibility, reciprocity, and reflection. These values can help us work towards a future where philanthropy is no longer needed.
Effect of processing conditions on electromagnetic shielding and electrical resistivity of injection‐molded polybutylene terephthalate compounds
Authors: Martins Luís C. , Barbosa Carlos N. , Silva Susana , Bernardo Pedro , Dias Gustavo R. , Pontes António J. 
Published: August 2021

AbstractThis research introduces an analysis of the anisotropic electrical resistivity (ER) and its relation to the electromagnetic shielding effectiveness (EMSE) for two injection‐molded carbon‐fiber‐reinforced polybutylene terephthalates (PBTs). The properties were measured for 2‐mm thick injection moldings considering the effect of melt temperature, injection velocity, and flow distance. The results for one compound showed an EMSE in the range of 30–40 dB, while EMSE for a compound with lower filler content is in the range of 45–75 dB. A combination of higher temperature and higher velocity leads to an increase of EMSE for both compounds in the range of 3%–8.5%. However, the increase in flow path reduced the EMSE for both compounds up to 10%. A novel experimental apparatus was used to measure the anisotropic ER in the three directions, that is, parallel, perpendicular, and transversal to flow. It is evident that injection molding induced high anisotropy for both compound specimens, and, depending on the processing conditions, produced similar longitudinal resistivity (0.2–4 Ω.cm) but higher transversal resistivity (8–22 Ω.cm). ER properties were compared with EMSE, evidencing an inverse relation as expected. Furthermore, it was found that the longitudinal resistivity is the main contributor to the specimens shielding.
Exploring the Hypoglycaemic Mechanism of Chinese Medicine Xiao‐Ke‐An Based on Target Dipeptidyl Peptidase 4 Using Molecular Docking and Dynamics Simulation
Authors: Yong‐Lin Wang , Yan Zhuang , Yan Tong , Yuan‐Fang Kong , Yu‐Long Hu , Jie‐Ming Li , Shao‐Pei Wang , Chun‐Hong Dong , Xiao‐Fei Li 
Published: August 2021

AbstractXiao‐Ke‐An is a traditional Chinese medicine formula for reducing the effects of diabetes by inhibiting dipeptidyl peptidase‐4 (DPP‐4) activity. However, its molecular mechanism is unclear owing to the complexity of its components. In this study, methods of molecular docking, molecular dynamics and molecular mechanics/Poisson Boltzmann surface area are combined for analysis. The main hypoglycaemic mechanism of Xiao‐Ke‐An involves multiple components. In particular, MOL003714 shows the strongest binding capacity with a binding free energy of −253.08 kJ mol−1 and thus could be a potent inhibitor of DPP‐4. Additionally, MOL007062 and MOL010404 show strong interactions with superoxide dismutase, tumour necrosis factor‐alpha and caspase‐3, indicating their ability to decrease the symptoms of type II diabetes by alleviating insulin resistance and reducing inflammatory reactions and oxidative stress. This study provides a theoretical basis for the discovery and modification of natural DPP‐4 inhibitors and details the role of Xiao‐Ke‐An.
Meta‐separation: Improvement of Properties by Molecular Design of Metamaterials for Organophosphorous Flame Retardants
Authors: Hwan Choi Kyoung , So Jeong Kim M. E. , Hack Suh Dong 
Published: August 2021

AbstractThe separation of liquid mixture has been studied for a long time. Separation proceeds based on the difference in physical properties including pore size and electrostatic interaction. Therefore, there are many difficulties in separation of materials having similar size and/or polarities in physical properties. Recently, meta‐separation which is novel separation strategy employing a metamaterial was reported. It utilizes the structural properties of metamaterials rather than electrostatic characteristics to separate water‐organic mixtures. Although it proposes a new method for separation of aqueous liquid mixtures, it has a low phase transition temperature and melting point. A newly designed and synthesized 12,12′,12′′,12′′′‐(pyrene‐4,5,9,10‐tetrayltetrakis(oxy))tetrakis(dodecan‐1‐ol)(PTOH) can significantly increase the thermal stability by replacing the end of the building block with a hydroxyl group. This dramatically improves the stability of the metamaterial in the xy plane through hydrogen bonding interaction, thereby increasing the phase transition temperature by 23.49 °C. Furthermore, organophosphorous flame retardants (OPFRs), critical hazardous organic compounds, are entirely eliminated from the water mixture by molecular metamaterial with PTOH.
Facile Fabrication of Novel SrMoO4/g‐C3N4 Hybrid Composite for High‐Performance Photocatalytic Degradation of Dye Pollutant under Sunlight
Authors: Gandamalla Ambedkar , Manchala Saikumar , Shanker Vishnu 
Published: August 2021

AbstractThe exploitation of the efficient hybrid composite materials for environmental remediation is highly demanding area. In the present work, pristine SrMoO4 (SMO), g‐C3N4 (G‐CN) and SrMoO4/g‐C3N4 (SMO/G‐CN) hybrid composite materials have been synthesized for the first time by facile mixing and heating methodology. The fabricated materials are subsequently characterized by various spectroscopic techniques. Phase analysis was carried out by PXRD study as well as morphology and elemental analysis were investigated by FE‐SEM, EDS and XPS studies. The thermal stability of synthesized materials was determined by TGA as well as optical properties were confirmed by UV‐Vis DRS and PL studies, electrochemical analysis by EIS studies. The results reveals the optimized SMO/G‐CN‐10 composite photocatalyst exhibits superior performance for the photocatalytic degradation of Rhodamine B (Rh B) dye under direct sunlight irradiation and rate of photocatalytic efficiency of SMO/G‐CN‐10 (0.0976 min−1) is 4 and 40 times higher as compared to those of pure G‐CN (0.0245 min−1) and SMO (0.0024 min−1) respectively. Good interfacial interactions between the G‐CN and SMO in SMO/G‐CN‐10 composite helps in the separation and efficient transfer of photo‐induced excitons by inhibiting the recombination of excitons. The trapping experiment results reveals that O2.− are the major reactive species. It was noted that our composite SMO/G‐CN‐10 is found to be stable even after four successive runs. Furthermore a suitable mechanism has been proposed for its enhanced photocatalytic activity. Altogether, in the present investigation, a new route for the synthesis of efficient visible light active photocatalysts has been reported which is not only beneficial for environmental remediation applications but might also be used for the water splitting and CO2 reduction.
Highly Dispersed Ru Nanoparticles on Boron‐Doped Ti3C2Tx (MXene) Nanosheets for Synergistic Enhancement of Electrocatalytic Hydrogen Evolution
Authors: Bat‐Erdene Munkhjargal , Batmunkh Munkhbayar , Sainbileg Batjargal , Hayashi Michitoshi , Bati Abdulaziz S. R. , Qin Jiadong , Zhao Huijun , Zhong Yu Lin , Shapter Joseph G. 
Published: August 2021

Abstract2D‐layered materials have attracted increasing attention as low‐cost supports for developing active catalysts for the hydrogen evolution reaction (HER). In addition, atomically thin Ti3C2Tx (MXene) nanosheets have surface termination groups (Tx: F, O, and OH), which are active sites for effective functionalization. In this work, heteroatom (boron)‐doped Ti3C2Tx (MXene) nanosheets are developed as an efficient solid support to host ultrasmall ruthenium (Ru) nanoparticles for electrocatalytic HER. The quantum‐mechanical first‐principles calculations and electrochemical tests reveal that the B‐doping onto 2D MXene nanosheets can largely improve the intermediate H* adsorption kinetics and reduce the charge‐transfer resistance toward the HER, leading to increased reactivity of active sites and favorable electrode kinetics. Importantly, the newly designed electrocatalyst based on Ru nanoparticles supported on B‐doped MXene (Ru@B–Ti3C2Tx) nanosheets shows a remarkable catalytic activity with low overpotentials of 62.9 and 276.9 mV to drive 10 and 100 mA cm−2, respectively, for the HER, while exhibiting excellent cycling stabilities. Moreover, according to the theoretical calculations, Ru@B–Ti3C2Tx exhibits a near‐zero value of Gibbs free energy (ΔGH* = 0.002 eV) for the HER. This work introduces a facile strategy to functionalize MXene for use as a solid support for efficient electrocatalysts.