bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational structure prediction provides a plausible mechanism for electron transfer by the outer membrane protein Cyc2 from Acidithiobacillus ferrooxidans
Authors: Jiang Virginia , Khare Sagar D. , Banta Scott 
Published: May 2021

AbstractCyc2 is the key protein in the outer membrane of Acidithiobacillus ferrooxidans that mediates electron transfer between extracellular inorganic iron and the intracellular central metabolism. This cytochrome c is specific for iron and interacts with periplasmic proteins to complete a reversible electron transport chain. A structure of Cyc2 has not yet been characterized experimentally. Here we describe a structural model of Cyc2, and associated proteins, to highlight a plausible mechanism for the ferrous iron electron transfer chain. A comparative modeling protocol specific for trans membrane beta barrel (TMBB) proteins in acidophilic conditions (pH ~ 2) was applied to the primary sequence of Cyc2. The proposed structure has three main regimes: Extracellular loops exposed to low‐pH conditions, a TMBB, and an N‐terminal cytochrome‐like region within the periplasmic space. The Cyc2 model was further refined by identifying likely iron and heme docking sites. This represents the first computational model of Cyc2 that accounts for the membrane microenvironment and the acidity in the extracellular matrix. This approach can be used to model other TMBBs which can be critical for chemolithotrophic microbial growth.
Removal of Cr (VI) from aqueous solutions using clinoptilolite modified by TiO2 and polyoxypropylene surfactant
Authors: Soleimani Mohsen , Amini Nasibeh 
Published: May 2021

AbstractDue to their toxicity, the removal of heavy metal contaminants, particularly from aqueous solutions, is an important issue for the remediation field. This paper describes the performance of photocatalytic reduction of hexavalent chromium (Cr [VI]) using clinoptilolite as a natural zeolite (Ze) modified by titanium dioxide (TiO2 or Ti) and polyoxypropylene (POP) surfactant. The removal efficiency of the modified Ze was evaluated in the presence of Ze–Ti–POP and Ze–Ti nanocomposites under UV‐A irradiation and visible light. The effects of different factors including contact time (0–330 min), adsorbent dose (2, 4, 6, 8, and 10 g/L), initial pH (1, 2, 3, 4, and 5), and initial Cr (VI) concentration (5, 10, 15, 20, and 25 mg/L) were studied. The results showed that maximum removal efficiencies of Cr (VI) by Ze–Ti and Ze–Ti–POP nanocomposites in the optimum experimental conditions (i.e., contact time: 30 min, dose: 10 g/L, pH: 2, initial concentration: 10 mg/L) under UV‐A irradiation were 88% and 97%, while the corresponding reductions for visible light were 80% and 91%, respectively. Adsorption kinetics data fit well with the pseudo‐second‐order model. Furthermore, reusing nanocomposites after three regeneration cycles revealed that the application of Ze–Ti and Ze–Ti–POP nanocomposites could be a promising approach for removing Cr (VI) from aqueous solutions.
Improved fixed‐time stability results and application to synchronization of discontinuous neural networks with state‐dependent switching
Authors: Abdurahman Abdujelil , Jiang Haijun , Hu Cheng 
Published: May 2021

AbstractIn this article, we considered the fixed‐time stability (FXT) of a type of discontinuous dynamical system. First, we introduced some new FXT stability results via variable substitutions and using inequality techniques, which are more accurately estimate the upper bound of settling time (ST). Then, based on the established results and using the differential inclusion theory, we investigated the FXT synchronization of a type of general neural networks (NNs) with state‐dependent switching coefficients and discontinuous neuron activation functions via introducing a type of discontinuous controller which is more simple compared to existing results. In addition, the estimated upper bound of ST shown to be independent to the initial values of considered drive‐response networks, and it is much smaller and nearer to the real synchronization time than those given in the previously published works. Lastly, two numerical examples are given to demonstrate the feasibility of our derived theoretical results. We believe that the results of this article can give some new insights for the FXT stabilization and FXT synchronization analysis of state‐dependent switching dynamics with or without discontinuous right‐hand sides.
Rapid and Effective Ultrasonic‐Assisted Adsorptive Removal of Congo Red onto MOF‐5 Modified by CuCl2 in Ambient Conditions: Adsorption Isotherms and Kinetics Studies
Authors: Mosavi Seyed Hossein , Zare‐Dorabei Rouholah , Bereyhi Mohammad 
Published: May 2021

AbstractIn this study, ultrasonic‐assisted removed Congo red by MOF‐5/Cu as a metal‐organic framework, making the adsorption process very fast. Ultrasonic has proven to be a handy tool in accelerating dyes′ adsorption by enhancing the adsorbent‘s affinity and the adsorbent. MOF‐5 synthesized the solvothermal method and then modified it by CuCl2 in ambient conditions. Scanning Electron Microscope (SEM), X‐ray Diffraction (XRD), Fourier Transform Infrared (FT‐IR), Brunauer‐Emmett‐Teller (BET), and Thermogravimetric analysis (TGA) were used for the identification structure and morphology of MOF‐5/Cu. Sonication had an essential role in shortening the adsorption time (2 min) of Congo red by enhancing the dispersion of adsorbent (MOF‐5) in solution. Congo red concentration was measured with a UV‐visible spectrometer apparatus. Optimal values of Congo red concentration, Dosage of MOF‐5/Cu, time, and pH were obtained by Central composite design. According to the optimal parameters, the adsorption process was very rapid. Removal of Congo red happened with excellent adsorption capacity (357.42 mg g−1). Also, the MOF‐5/Cu was regenerating by acetone five‐time and show good results. Repeatability of the adsorption process was carried out, and the Relative Standard Deviation (RSD) was obtained 1.85 %.
Lewis‐Acid‐Mediated One‐Pot Tandem Reactions for Synthesis of Structurally Diverse Furo[3,2‐c]coumarins
Authors: Chen Zhiwei , Zeng Piaopiao , Zhang Shuo , Huang Xiaoxiao 
Published: May 2021

AbstractA concise, one‐pot route for the synthesis of furo[3,2‐c]‐coumarins under the catalysis of Zn(OTf)2 is reported. Utilizing this synthetic strategy, libraries of furocoumarin analogues can be easily obtained by multicomponent tandem reactions with different nucleophile in the presence of 4‐hydroxycoumarin and arylglyoxal monohydrate system, This transformation exhibited highly atom economical and good functional group compatibility.
Topological Radiated Dendrites Featuring Persistent Bactericidal Activity for Daily Personal Protection
Authors: Li Zhiheng , Wang Jie , Shen Ruichen , Chen Na , Qin Xinyuan , Wang Wenjie , Yuan Quan 
Published: May 2021

AbstractMany substances in nature show radiated topological structure and possess excellent bio‐adhesion ability. Herein, regulating the topological structure of Zn2GeO4:Mn persistent phosphors is achieved with a molecular coordination method. The morphology of the Zn2GeO4:Mn phosphors is well‐tuned from nanorods to radiated dendrites by changing the coordination capability of the surface ligand. Due to the structural matching and multivalent interactions, Zn2GeO4:Mn radiated dendrites show strong adhesion affinity toward organisms. Moreover, the porous radiated structure offers Zn2GeO4:Mn with a large surface area for photocatalysis. Efficient bacterial adhesion and good long persistent photocatalysis activity are observed in the Zn2GeO4:Mn radiated dendrites, which endows Zn2GeO4:Mn with persistent antibacterial activity even in the dark. Further, the Zn2GeO4:Mn spike flowers loaded fabrics exhibit potent persistent antibacterial properties. Mask and towel fabricated with the antibacterial fabrics can inhibit bacterial growth effectively and no bacteria are observed to pass through the antibacterial mask, suggesting that antibacterial mask can guarantee our health and can be utilized repeatedly. The developed Zn2GeO4:Mn dendrites possess ideal ability in long‐term bacterial inhibition, making them valuable in the fields of medical protection and food packaging.
Mechanical and barrier properties of polyvinyl chloride plasticized with dioctyl phthalate, epoxidized soybean oil, and epoxidized cardanol
Authors: Satapathy Sukanya , Palanisamy Aruna 
Published: May 2021

AbstractPlasticized polyvinyl chloride (PVC) films were prepared by melt compounding and compression molding using epoxidized cardanol (EC), a biobased plasticizer and its plasticization effect was compared with epoxidized soybean oil (ESBO) and dioctyl phthalate (DOP). The mechanical, migration, thermal, and barrier properties of the plasticized films were compared. The effect of replacing DOP with EC on the properties of PVC films was also investigated. The tensile strength, elongation at break, tensile modulus and impact strength values of PVC/EC films were higher in comparison to PVC/DOP and PVC/ESBO films at a fixed plasticizer loading of 40 wt.%. Also, the films prepared with a mixture of DOP + EC showed higher tensile strength and elongation at break compared to that of films prepared with only DOP. The PVC/EC films showed good thermal stability and reduced oxygen transmission rate (OTR) compared to PVC/DOP films. The addition of graphene and nanoclay in the PVC/plasticizer system exhibited an increase in oxygen transmission. However, the oxygen barrier property of nano filler incorporated PVC/EC films was better than PVC/DOP films. All the films showed negligible water vapor transmission rate (WVTR).
Technological Advances Increase Fix‐Success for White‐Tailed Deer GPS Collars
Authors: Smith Bradley D. , Delgiudice Glenn D. , Severud William J. 
Published: May 2021

ABSTRACTThe incorporation of quick fix pseudoranging (QFP) technology into global positioning system (GPS) collars has the potential to increase location‐fix success for terrestrial species. Units enabled with QFP obtain the data necessary to calculate an accurate GPS location‐fix during post‐processing with just a 3–5 second view of a satellite constellation. Fix‐success rate is one of the main sources of error in GPS telemetry studies, creating an inherent bias resulting in misleading data interpretations and incorrect inferences about habitat use. During winter 2017–2018, we captured 20 adult female white‐tailed deer (Odocoileus virginianus) and fitted them with QFP‐enabled GPS collars on 2 study areas (10/site) in northcentral and northeastern Minnesota, with an additional 40 collars (20/site) deployed during winter 2018–2019. Prior to deployment of the GPS collars on free‐ranging deer, we conducted stationary tests to evaluate location‐fix‐success and spatial accuracy of 48 (of the 60) collars distributed among 4 different vegetative cover types. We recovered 100% of the expected 3,024 location‐fixes during the stationary tests. The overall mean location error of the GPS collars was 5.7 m (±0.15 [SE], range = 0–189 m), with errors in dense conifer (10.3 ± 0.52, range = 0–189 m) being greater than in hardwood stands (6.2 ± 0.22, range = 0–91 m), browse patches (3.2 ± 0.08, range = 0–26 m), and openings (3.2 ± 0.08, range = 0–32 m). Similarly, we evaluated the performance of 30 collars deployed on free‐ranging deer. We deployed collars for a mean 79.5 days (±7.22, range = 1.8–153.8 days) with a fix‐success rate of 100% (34,758 location‐fixes); QFP accounted for 11.3% of the 34,758 location‐fixes. Our results suggest that the addition of QFP capabilities effectively increased fix‐success of GPS collars on free‐ranging deer by 11%. An increase in fix‐success rate can be of considerable value to movement, distribution, and habitat selection studies, where bias associated with missing data can create unreliable or even false inferences. © 2021 The Wildlife Society.
Preparation and Reactivity Studies of Four and Five coordinated Amidinate Aluminum Compounds
Authors: Banerjee Samya , Kumar Chowan Ashok , Bose Sanjoy , Sarkar Samir Kumar , Gupta Sandeep K , Graw Nico , Köhler Christian , Herbst‐Irmer Regine , Stalke Dietmar , Dutta Sayan , Koley Debasis , Roesky Herbert W. 
Published: May 2021

AbstractSynthesis of four and five coordinated aluminum amidinate (PhC(NtBu)2=L) compounds are reported herein along with their single‐crystal X‐ray structures and detailed characterizations using both, experimental and computational techniques. LAlCl2 (1) and L2AlCl (2) were synthesized by treating AlCl3 with PhC(NtBu)2Li in an equivalent ratio of 1 : 1 and 1 : 2, respectively. [LAl(C2H5)Cl] (3) was prepared from a reaction of AlCl2(C2H5) with PhC(NtBu)2Li in an equivalent ratio of 1 : 1. Reactivity of 3, an amidinate based organo‐aluminum compound is explored for the various reactions. 3 produced [LAl(C2H5)(μ‐F)]2 (4) on treatment with Me3SnF. Interestingly, [LAl(C2H5)Cl] (3) was converted to [LAlCl(μ‐OEt)]2 (5) when refluxed in Et2O. 3 gives the monomeric and neutral cyclic (alkyl)(amino) carbene (cAAC) based radical [LAl(C2H5)(cAAC)] (6) on reduction with KC8 in the presence of cAAC.
Visitor presence and a changing soundscape, alongside environmental parameters, can predict enclosure usage in captive flamingos
Authors: Rose Paul , Badman‐King Alexander , Hurn Samantha , Rice Tom 
Published: May 2021

AbstractThe sound environment of a zoo animal is a complex milieu of animal and human‐generated sounds; coming from the species itself, other species, visitors, keepers and other zoo‐users. Research determining how different components of the sound environment affect animal behaviour is surprisingly lacking but could have real‐world impacts for animal welfare and zoo enclosure design. The current study investigated the effects of the sound environment on two flocks of flamingos housed in open‐air enclosures at British zoos. Measures of how each flock used its enclosure (as a response variable) and environmental variables (Inband Power and Peak Frequency were recorded as characteristics of the sound environment, as well as temperature, humidity and cloud cover, and finally visitor presence—all as potential predictor variables) were made over a 2‐month period. Assessment of space use by zoo animals is often used as a measure of the appropriateness of an exhibit and to understand welfare. Given that flamingo activity is influenced by weather and that the sound environment of the zoo is likely to be influenced by the number and the presence of visitors, it was assumed that these predictor variables would influence where the flamingos were located at different times of the day. As expected, there was a complicated relationship between enclosure use and Inband Power (average spectral density, a measure of sound energy) in both flocks; visitors generated salient sound but other visitor characteristics such as their physical presence may have impacted the movement of the birds around their enclosures. Results show a complex picture where environmental conditions influence flamingo enclosure usage as well as visitor presence and sounds around/in the enclosure. Findings are not consistent between the two flocks, with one flock demonstrating distinct temporal change to enclosure zone occupancy and the other responsive to humidity and cloud cover variation. We believe enclosure use can provide a valuable indication of how birds react to their soundscape; however, our findings suggest more work is needed to unpick the components of captive sound environments, and their relative effects on how animals use their space.
Perceptions and Explanations of Environmental Change in Morocco
Authors: Van Praag Lore 
Published: May 2021

AbstractAs demonstrated in the previous chapters, land in Morocco is mainly used for farming and pastoral activities. These activities are more vulnerable to the consequences of increased precipitation and drought due to climate change. Various modern and traditional adaptation strategies – among which migration to urban centres or abroad – have been used to deal with environmental changes. This suggests that a large share of inhabitants are in some way aware of the changes in their natural environment and already familiar with adaptation strategies (Schilling et al. 2012; Mertz et al. 2009). However, in most studies, researchers focusing on this topic do not relate this to people’s overall views on environmental change and the adaptation strategies employed by the actors involved. When they do, they hardly focus on people living in the MENA region (Nielsen and D’haen 2014); West-Africa (Mertz et al. 2010, 2012; Afifi 2011; De Longueville et al. 2020); DR Congo (Bele et al. 2014; Few et al. 2017); and India (Howe et al. 2014). The only exception is the study on Morocco by Nguyen and Wodon (2014); Wodon et al. 2014). Hence, it is unclear how these environmental changes are actually perceived and how they influence the ways people view and respond to them, and (actively) develop adaptation strategies to deal with such changes (cf. Chap.10.1007/978-3-030-61390-7_6). This is especially important since perceptions of environmental changes and the risks associated with them vary across and within cultures (Vedwan 2006; Mertz et al. 2009, 2010; Leclerc et al. 2013). Furthermore, there is a perception bias with regard to the perceived environmental changes, as some types of changes, such as rainfall patterns, are more easily noted and compared to others, such as temperature changes (Howe et al. 2014; Few et al. 2017; De Longueville et al. 2020; Bele et al. 2014). Additionally, people mainly remark on changes when these apply to their livelihood activities (Bele et al. 2014; Howe et al. 2014; Wodon et al. 2014; De Longueville et al. 2020). In current research and policymaking, ongoing debates on environmental migration and displacement too frequently assume that everyone perceives environmental change in a similar fashion. This becomes problematic in debates on environmental migration or climate refugees when environmental changes are assumed to automatically result in some kind of (forced) migration, leaving little space for the views and agency of the people involved (Stern 2000; McLeman and Gemenne 2018; Khare and Khare 2006; Rigby 2016).
Regularity and time behavior of the solutions to weak monotone parabolic equations
Authors: Porzio Maria Michaela 
Published: May 2021

AbstractIn this paper, we study the behavior in time of the solutions for a class of parabolic problems including thep-Laplacian equation and the heat equation. Either the case of singular or degenerate equations is considered. The initial datum$$u_0$$u0is a summable function and a reaction termfis present in the problem. We prove that, despite the lack of regularity of$$u_0$$u0, immediate regularization of the solutions appears for datafsufficiently regular and we derive estimates that for zero datafbecome the known decay estimates for these kinds of problems. Besides, even iffis not regular, we show that it is possible to describe the behavior in time of a suitable class of solutions. Finally, we establish some uniqueness results for the solutions of these evolution problems.
Influence of packing density and fillers on thermal conductivity of polymer powders for additive manufacturing
Authors: Sillani Francesco , de Gasparo Fabian , Schmid Manfred , Wegener Konrad 
Published: May 2021

AbstractAdditive manufacturing of polymer powders is nowadays an industrial production technology. Complex thermal phenomena occur during processing, mainly related to the interaction dynamics among laser, powder, and heating system, and also to the subsequent cool-down phase from the melt to the parts. Thermal conductivity of the powder is a key property for material processing, since an inhomogeneous temperature field in the powder cake leads to uneven part properties and can strongly limit productivity because only a smaller portion of the build chamber can be used. Nevertheless, little is known about the relationship between thermal conductivity, packing density, and presence of fillers, which are used to enhance specific properties such as high temperature resistance or stiffness. The development and consequent validation of a device capable of measuring thermal conductivity as a function of powder packing density are then extremely important, providing an additional tool to characterize powders during the development process of new materials for PBF of polymers. The results showed a positive correlation between packing density and thermal conductivity for some commercially available materials, with an increase of the latter of about 10 to 40% with an increase of the packing density from 0 to 100%. Problems arose in trying to replicate the compaction state of the powder, since the same amount of taps led to a different packing density, but this is a known problem of measuring free-flowing powders such as the ones used for additive manufacturing. Regarding fillers, an increase of about 40 to 70% of thermal conductivity when inorganic fillers such as carbon fibers are added to the neat polymer was observed, and the expected behavior following the rule of mixture was only partially observed.
Red grape skin extract and oat β-glucan in shortbread cookies: technological and nutritional evaluation
Authors: Szpicer Arkadiusz , Onopiuk Anna , Wojtasik-Kalinowska Iwona , Półtorak Andrzej 
Published: May 2021

AbstractConsumers are increasingly interested in innovative products enriched with nutrients that counteract the development of civilisation-associated diseases. Thus, the development of new functional nutrient-enriched food products that meet consumer needs is therefore necessary. The aims of this study were to develop a novel shortbread cookie product by addition of red grape skin extract and oatβ-glucan and to evaluate the influence of these modifications on physico‐chemical properties and consumer’s acceptance. The red grape skin extract used in this product is a source of polyphenols which are beneficial for human health and extend product shelf life.β-glucan is a soluble fraction of dietary fibre that helps to lower reduce blood cholesterol and glycemic levels. The influence of grape skin extract,β-glucan and a combination of both on theβ-glucan content, colour and texture parameters, thermal properties, total antioxidant activity, total phenolic content, volatile compounds profile and sensory properties of shortbread cookies was analysed. Product with modified formulations had higher total antioxidant activity, total phenolic content and were was more thermally stable than control samples. The obtained innovative functional products were characterized by an increased content of oatβ-glucan, which is desirable from a nutritional point of view. The DSC measurements showed higher oxidative stability of cookies enriched withβ-glucan and red grape skin extract. The additives caused significant changes in the colour and profile of volatile compounds of the finished final product but did not affect the sensory acceptance among consumers. The use of these additives represents a development in food technology that may be valuable in the food industry to increase the nutritional value and extend the shelf shelf-life of bakery products.