bluuebunny/crossref_metadata_2025 huggingface dataset:
Iron(III), copper(II), cadmium(II), and mercury(II) complexes of isatin carbohydrazone Schiff base ligand (H3L): Synthesis, characterization, X‐ray diffraction, cyclic voltammetry, fluorescence, density functional theory, biological activity, and molecular docking studies
Authors: Younis Adel M. , El‐Gamil Mohammed M. , Rakha Tawfik H. , Abu El‐Reash Gaber M.
Published: March 2021

A series of some transition metal, Fe(III), Cu(II), Cd(II), and Hg(II), complexes withN′,2‐bis((Z)‐2‐oxoindolin‐3‐ylidene)hydrazine‐1 carbohydrazide (H3L) ligand have been synthesized, and their structures were elucidated based on their spectral analyses (Fourier transform infrared [FT‐IR],1H nuclear magnetic resonance (NMR) and13C NMR, UV‐visible (UV‐Vis), electron spin resonance (ESR), powder X‐ray diffraction [XRD], and mass spectroscopy), elemental analyses, conductance, and magnetic susceptibility measurements. The structures of the H3L ligand and its metal complexes were optimized using the DMol3tool in the material studio package. The ligand behaves as binegative N2O3pentadentate in [Fe(HL)(Cl)]·2H2O complex, mononegative N2O3pentadentate in [Cu(H2L)(OAc)]·2H2O complex, mononegative N2O tridentate in [Cd(H2L)2]·H2O complex, and finally, neutral N2bidentate in [Hg(H3L)(Cl)2]·2H2O complex. Coats–Redfern and Horowitz–Metzger methods were used to estimate the various thermodynamic and kinetic parameters. Cyclic voltammetry of the ligand in the absence and presence of Cd(II) and Hg(II) ions was studied. Fluorescence studies were performed in DMSO and showed that Cu(II) ions quench the fluorescence spectrum of the free ligand, whereas Cd(II) ions enhance it. The in vitro antimicrobial activities of the free ligand and its complexes against different bacterial strains and fungiCandida albicanswere screened using agar‐disc diffusion techniques. The antioxidant potentials of the isolated compounds were also screened by employing SOD and ABTS free radical scavenging methods. Molecular docking studies were performed using Auto‐Dock tools to predict the best binding mode and predominant binding interactions.
Ag‐CdS Yolk–Shell Heteronanostructures for Plasmon‐Enhanced Photocatalysis
Authors: Jung Hayoon , Whang Youngjoo , Han Sang Woo
Published: March 2021

The combination of a semiconductor and a plasmonic metal holds great promise for developing advanced photocatalysts. However, the realization of a heteronanostructure that accommodates both materials in an effective way has been a great challenge. Herein, we report a synthesis of a photocatalyst with a yolk–shell heteronanostructure, which contains a plasmonic Ag yolk inside a CdS shell. The sulfidation of Ag nanospheres followed by a controlled cation exchange reaction successfully generated the Ag‐CdS yolk–shell nanostructures. The as‐prepared heteronanostructures exhibited a prominent enhancement of photocatalytic activity toward hydrogen evolution reaction under visible‐light irradiation compared to CdS hollow nanoparticles without the Ag yolk. This improvement can be attributed to the plasmon energy transfer from the Ag yolk to the CdS shell and the yolk–shell structure that enables the multiple reflections of the incident light.
Comparison of Two DNA Aptamers for Dopamine Using Homogeneous Binding Assays
Authors: Hou Yaoyao , Hou Jianjun , Liu Xixia
Published: March 2021

Dopamine is an essential neurotransmitter and its detection is important for bioanalytical chemistry. Two very different DNA aptamers have been reported for dopamine, one derived from an RNA aptamer (named Apt1) and other obtained via direct aptamer selection (named Apt2). In this study, we used four homogeneous binding assays to compare these two DNA dopamine aptamers. Thiazole orange (TO) fluorescence assay indicated that the Apt2 specifically bound with dopamine with a Kd of 2.37 μM, which was consistent with that from the isothermal titration calorimetry (ITC) assay. However, Apt1 had much less TO fluorescence change and also no signal from ITC. By labeling the two ends of the two aptamers by a fluorophore and a quencher, the aptamer beacons showed binding of dopamine only for Apt2. Finally, the label‐free AuNP‐based colorimetric assay showed no difference between these two aptamer sequences, and even non‐binding random DNA showed the same response, indicating that AuNPs were not a good probe for detecting dopamine. According to the data, Apt1 does not appear to be able to bind dopamine specifically, while Apt2 showed specific binding and could be used for developing related biosensors.
Enantioconvergent Substitution Reactions of Racemic Electrophiles by Organocatalysis
Authors: Kikuchi Jun , Terada Masahiro
Published: March 2021

Over the past decades, the development of enantioselective catalysis using organocatalysts has evolved into an active research field and a number of enantioselective transformations have been established. However, despite their being a highly desirable process for the synthesis of organic molecules in an enantioenriched form, the enantioconvergent substitution reactions of racemic electrophiles using organocatalysts still present several challenges. Although intrinsic difficulties in the catalytic stereocontrol abound due to the initial chiral information of racemic electrophiles, in recent years, mechanistically diverse enantioconvergent processes have been intensively investigated in organocatalysis. This Minireview focuses on recent achievements in the development of enantioconvergent substitution reactions of racemic electrophiles using organocatalysts. The contents are classified on the basis of the mechanistic types of enantioconvergent processes.
Stochastic gradient descent‐based support vector machines training optimization on Big Data and HPC frameworks
Authors: Abeykoon Vibhatha , Fox Geoffrey , Kim Minje , Ekanayake Saliya , Kamburugamuve Supun , Govindarajan Kannan , Wickramasinghe Pulasthi , Perera Niranda , Widanage Chathura , Uyar Ahmet , Gunduz Gurhan , Akkas Selahatin
Published: March 2021

Support vector machines (SVM) is a widely used machine learning algorithm. With the increasing amount of research data nowadays, understanding how to do efficient training is more important than ever. This article discusses the performance optimizations and benchmarks related to providing high‐performance support for SVM training. In this research, we have focused on a highly scalable gradient descent‐based approach to implementing the core SVM algorithm. In providing a scalable solution, we have designed optimized high‐performance computing and dataflow‐oriented SVM implementations. A high‐performance computing approach means the algorithm is implemented with the bulk synchronous parallel (BSP) model. In addition, we analyzed the language level optimizations and math kernel optimizations on a prominent HPC modeling programming language (C++) and dataflow modeling programming language (Java). In the experiments, we compared the performance of classic HPC models, classic dataflow models, and hybrid models designed on classic HPC and dataflow programming models. Our research illustrates a scientific approach in designing the SVM algorithm at scale in classic HPC, dataflow, and hybrid systems.
Recent Advances in Design Strategies for Tough and Stretchable Hydrogels
Authors: Maiti Chiranjit , Imani Kusuma Betha Cahaya , Yoon Jinhwan
Published: March 2021

The development of multifunctional hydrogels with excellent stretchability and toughness is one of the most fascinating subjects in soft matter research. Numerous research efforts have focused on the design of new hydrogel systems with superior mechanical properties because of their potential applications in diverse fields. In this Minireview, we consider the most up‐to‐date mechanically strong hydrogels and summarize their design strategies based on the formation of double networks and dual physical crosslinking. Based on the synthetic approaches and different toughening mechanisms, double‐network hydrogels can be further classified into three different categories, namely chemically crosslinked, hybrid physically–chemically crosslinked, and fully physically crosslinked. In addition to the above‐mentioned methods, we also discuss few uniquely designed hydrogels with the intention of guiding the future development of these fascinating materials for superior mechanical performance.
A systematic review of metacognitions in Internet Gaming Disorder and problematic Internet, smartphone and social networking sites use
Authors: Casale Silvia , Musicò Alessia , Spada Marcantonio M.
Published: March 2021

Background

The use of new technologies is growing, and some authors have suggested that frequent use might hide a non‐chemical addiction (i.e., technological addiction). Over the last 5 years, several studies investigating the role of metacognitions in technological addictions have been published. We aim to provide the first systematic review focused on this topic, by updating the initial evidence highlighted by a previous systematic review on metacognitions across addictive behaviours (Hamonniere & Varescon, 2018).

Methods

Electronic literature databases (Pubmed, PsychINFO, SCOPUS and Web of Science) were searched to identify studies that examined the relationship between metacognitions and four different technological addictions (Internet Gaming Disorder, IGD; problematic Internet use, PIU; problematic smartphone use, PSU; and problematic social networking sites use, PSNSU).

Results

We found 13 empirical studies published between 2018 and 2021. Positive low to moderate cross‐sectional associations between the four technological addictions and both generic and specific metacognitions were found, in accordance with the metacognitive model of addictive behaviours. Positive beliefs about worry, negative beliefs about thoughts concerning uncontrollability and danger, beliefs about the need to control thoughts and a lack of cognitive confidence were associated with IGD, PIU, PSU and PSNSU.

Conclusions

The absence of longitudinal studies prevents us from providing definitive answers about the role of metacognitions in technological addictions. Despite this limitation, interventions that target metacognitions could be beneficial for people presenting with technological addictions.
An intermodulation distortion estimation method for linear CMOS circuits
Authors: Baxevanakis Dimitrios , Alimisis Vassilis , Sotiriadis Paul P.
Published: March 2021

This article presents a general, time‐domain method for intermodulation distortion estimation that offers a fast, systematic, and compact formulation. It can be applied to any linear CMOS circuit architecture, with any number of stages, ranging from amplifiers and transconductors to filters, that are characterized by weakly nonlinear behavior. Each CMOS stage of the circuit is modeled as aGm‐stage with an output current expressed as a more involved function of its input and output voltages, taking into account both powers and cross‐product terms necessary to accurately capture the nonlinear behavior. The proposed method is easily implemented in numerical computing environments like MATLAB or Python and results in a very fast distortion estimation. A number of example topologies simulated in Cadence Spectre illustrate the application of the method and demonstrate its accuracy.
Microcomputed tomography used to link head morphology and observed feeding behavior in cichlids of Lake Malaŵi
Authors: Konings Adrianus F. , Wisor Joshua M. , Stauffer Jay R.
Published: March 2021

Cichlids inhabiting the Great Lakes of Africa have radiated extremely rapidly, with Lake Malaŵi harboring some 850 species. This rapid radiation may be linked to the diversity in behaviors, sexual selection, and phenotypic plasticity. To determine the relationships between morphology and behaviors, microcomputed tomography (microCT) was used to observe internal morphological structures. Observed morphological adaptations were linked with observed behavior of cichlids in Lake Malaŵi with respect to the various available food resources. Many of these adaptations have parallels, sometimes into the finest details, in other drainage systems and can thus be considered as variations of how cichlids in general respond to environmental opportunities and challenges. Variations in the structure and teeth of the pharyngeal jaws and the oral jaws allowed for fine tuning of specializations, so that various species can utilize the same source without direct competition. We suggested that high‐resolution X‐ray computed tomography will permit scientists to infer life history and behavior characters of rare or extinct taxa from a detailed examination of morphology and linkages between morphology and behavior found in extant species.
Tackling unresolved questions in forest ecology: The past and future role of simulation models
Authors: Maréchaux Isabelle , Langerwisch Fanny , Huth Andreas , Bugmann Harald , Morin Xavier , Reyer Christopher P.O. , Seidl Rupert , Collalti Alessio , Dantas de Paula Mateus , Fischer Rico , Gutsch Martin , Lexer Manfred J. , Lischke Heike , Rammig Anja , Rödig Edna , Sakschewski Boris , Taubert Franziska , Thonicke Kirsten , Vacchiano Giorgio , Bohn Friedrich J.
Published: March 2021

Understanding the processes that shape forest functioning, structure, and diversity remains challenging, although data on forest systems are being collected at a rapid pace and across scales. Forest models have a long history in bridging data with ecological knowledge and can simulate forest dynamics over spatio‐temporal scales unreachable by most empirical investigations.

We describe the development that different forest modelling communities have followed to underpin the leverage that simulation models offer for advancing our understanding of forest ecosystems.

Using three widely applied but contrasting approaches – species distribution models, individual‐based forest models, and dynamic global vegetation models – as examples, we show how scientific and technical advances have led models to transgress their initial objectives and limitations. We provide an overview of recent model applications on current important ecological topics and pinpoint ten key questions that could, and should, be tackled with forest models in the next decade.

Synthesis. This overview shows that forest models, due to their complementarity and mutual enrichment, represent an invaluable toolkit to address a wide range of fundamental and applied ecological questions, hence fostering a deeper understanding of forest dynamics in the context of global change.
Genomic divergence in sympatry indicates strong reproductive barriers and cryptic species within Eucalyptus salubris
Authors: Binks Rachel M. , Steane Dorothy A. , Byrne Margaret
Published: March 2021

Genetic studies are increasingly detecting cryptic taxa that likely represent a significant component of global biodiversity. However, cryptic taxa are often criticized because they are typically detected serendipitously and may not receive the follow‐up study required to verify their geographic or evolutionary limits. Here, we follow‐up a study of Eucalyptus salubris that unexpectedly detected two divergent lineages but was not sampled sufficiently to make clear interpretations. We undertook comprehensive sampling for an independent genomic analysis (3,605 SNPs) to investigate whether the two purported lineages remain discrete genetic entities or if they intergrade throughout the species’ range. We also assessed morphological and ecological traits, and sequenced chloroplast DNA. SNP results showed strong genome‐wide divergence (FST = 0.252) between two discrete lineages: one dominated the north and one the southern regions of the species’ range. Within lineages, gene flow was high, with low differentiation (mean FST = 0.056) spanning hundreds of kilometers. In the central region, the lineages were interspersed but maintained their genomic distinctiveness: an indirect demonstration of reproductive isolation. Populations of the southern lineage exhibited significantly lower specific leaf area and occurred on soils with lower phosphorus relative to the northern lineage. Finally, two major chloroplast haplotypes were associated with each lineage but were shared between lineages in the central distribution. Together, these results suggest that these lineages have non‐contemporary origins and that ecotypic adaptive processes strengthened their divergence more recently. We conclude that these lineages warrant taxonomic recognition as separate species and provide fascinating insight into eucalypt speciation.
Changes in the Montagu’s Harrier Circus pygargus diet in Eastern Poland across decades promote insects and reptilians, but not birds and rodents
Authors: Kitowski Ignacy , Jakubas Dariusz , Mirski Paweł , Pitucha Grzegorz , Markowska Kornelia
Published: March 2021

We investigated temporal changes in diet composition of the Montagu's HarrierCircus pygargusbreeding in natural habitat (calcareous peat bog) in SE Poland. We characterized diet composition in a three‐year period (2007–2009), based on pellet analyses. We investigated whether diet composition was affected by years or stage of breeding. We compared diet of the studied population between 2000s and 1990s and with other populations. We found that the food of the studied population was dominated by insects and mammals (by number) and mammals and birds (by biomass). Biomass and abundance of main prey items differed between studied years because of different air temperatures. We found some interannual differences in contribution of some prey items including higher number of thermophilic prey (insects and amphibians) in warmer years. Comparison of pellet composition in the 1990s and 2000s revealed significant increase in the abundance of thermophilic prey (insects and reptiles) and decrease of mammals includingMicrotusvoles and birds. Those changes may be linked to habitat changes in areas neighboring peat bogs and climate change‐induced changes in prey communities. The studied population was able to respond to changes in foraging habitats and prey composition by opportunistic foraging on easily available prey. The diet of the studied population is the most similar to the geographically closest populations foraging in similar habitats and characterized by high contribution of insects.
Past connections with the mainland structure patterns of insular species richness in a continental‐shelf archipelago (Aegean Sea, Greece)
Authors: Hammoud Cyril , Kougioumoutzis Konstantinos , Rijsdijk Kenneth F. , Simaiakis Stylianos M. , Norder Sietze J. , Foufopoulos Johannes , Georgopoulou Elisavet , Van Loon Emiel E.
Published: March 2021

Recent research in island biogeography has highlighted the important role of late Quaternary sea‐level fluctuations in shaping biogeographic patterns in insular systems but focused on oceanic systems. Through this study, we aim investigate how late Quaternary sea‐level fluctuations shaped species richness patterns in continental‐shelf island systems. Focusing on the Aegean archipelago, we first compiled maps of the area's geography using published data, under three sea‐level stands: (a) current; (b) median sea‐level over the last nine glacial–interglacial cycles (MSL); and (c) Last Glacial Maximum (LGM). We gathered taxon–island occurrences for multiple chorotypes of angiosperms, butterflies, centipedes, and reptiles. We investigated the impact of present‐day and past geographic settings on chorological groups by analyzing island species–area relationships (ISARs) and using generalized linear mixed models (GLMMs) selection based on multiple metrics of goodness of fit. Our results confirm that the Aegean's geography has changed dramatically since the LGM, whereas the MSL only modestly differs from the present configuration. Apart for centipedes, paleogeographic changes affected both native and endemic species diversity through altering connections between land‐bridge islands and the mainland. On land‐bridge islands, we detected over‐representation of native species and under‐representation of endemics. Unlike oceanic islands, sea‐level‐driven increase of isolation and area contraction did not strongly shape patterns of species richness. Furthermore, the LGM configurations rather than the MSL configuration shaped patterns of endemic species richness. This suggests that even short episodes of increased connectivity with continental populations are sufficient to counteract the genetic differentiation of insular populations. On the other hand, the over‐representation of native nonendemic species on land‐bridge islands reflected MSL rather than LGM mainland connections. Our study shows that in terms of processes affecting species richness patterns, continental archipelagos differ fundamentally from oceanic systems because episodic connections with the mainland have profound effects on the biota of land‐bridge islands.
Prey and predator density‐dependent interactions under different water volumes
Authors: Cuthbert Ross N. , Dalu Tatenda , Wasserman Ryan J. , Sentis Arnaud , Weyl Olaf L. F. , Froneman P. William , Callaghan Amanda , Dick Jaimie T. A.
Published: March 2021

Predation is a critical ecological process that directly and indirectly mediates population stabilities, as well as ecosystem structure and function. The strength of interactions between predators and prey may be mediated by multiple density dependences concerning numbers of predators and prey. In temporary wetland ecosystems in particular, fluctuating water volumes may alter predation rates through differing search space and prey encounter rates. Using a functional response approach, we examined the influence of predator and prey densities on interaction strengths of the temporary pond specialist copepodLovenula rayneraepreying on cladoceran prey,Daphnia pulex, under contrasting water volumes. Further, using a population dynamic modeling approach, we quantified multiple predator effects across differences in prey density and water volume. Predators exhibited type II functional responses under both water volumes, with significant antagonistic multiple predator effects (i.e., antagonisms) exhibited overall. The strengths of antagonistic interactions were, however, enhanced under reduced water volumes and at intermediate prey densities. These findings indicate important biotic and abiotic contexts that mediate predator–prey dynamics, whereby multiple predator effects are contingent on both prey density and search area characteristics. In particular, reduced search areas (i.e., water volumes) under intermediate prey densities could enhance antagonisms by heightening predator–predator interference effects.
Soil biogeochemistry across Central and South American tropical dry forests
Authors: Waring Bonnie G. , De Guzman Mark E. , Du Dan V. , Dupuy Juan M. , Gei Maga , Gutknecht Jessica , Hulshof Catherine , Jelinski Nicolas , Margenot Andrew J. , Medvigy David , Pizano Camila , Salgado‐Negret Beatriz , Schwartz Naomi B. , Trierweiler Annette M. , Van Bloem Skip J. , Vargas G. German , Powers Jennifer S.
Published: March 2021

The availability of nitrogen (N) and phosphorus (P) controls the flow of carbon (C) among plants, soils, and the atmosphere, thereby shaping terrestrial ecosystem responses to global change. Soil C, N, and P cycles are linked by drivers operating at multiple spatial and temporal scales: landscape‐level variation in macroclimate and soil geochemistry, stand‐scale heterogeneity in forest composition, and microbial community dynamics at the soil pore scale. Yet in many biomes, we do not know at which scales most of the biogeochemical variation emerges, nor which processes drive cross‐scale feedbacks. Here, we examined the drivers and spatial/temporal scales of variation in soil biogeochemistry across four tropical dry forests spanning steep environmental gradients. To do so, we quantified soil C, N, and P pools, extracellular enzyme activities, and microbial community structure across wet and dry seasons in 16 plots located in Colombia, Costa Rica, Mexico, and Puerto Rico. Soil biogeochemistry exhibited marked heterogeneity across the 16 plots, with total organic C, N, and P pools varying fourfold, and inorganic nutrient pools by an order of magnitude. Most soil characteristics changed more across space (i.e., among sites and plots) than over time (between dry and wet season samplings). We observed stoichiometric decoupling among C, N, and P cycles, which may reflect their divergent biogeochemical drivers. Organic C and N pool sizes were positively correlated with the relative abundance of ectomycorrhizal trees and legumes. By contrast, the distribution of soil P pools was driven by soil geochemistry, with larger inorganic P pools in soils with P‐rich parent material. Most earth system models assume that soils within a texture class operate similarly, and ignore subgrid cell variation in soil properties. Here we reveal that soil nutrient pools and fluxes exhibit as much variation among four Neotropical dry forests as is observed across terrestrial ecosystems at the global scale. Soil biogeochemical patterns are driven not only by regional differences in soil parent material and climate, but also by local‐scale variation in plant and microbial communities. Thus, the biogeochemical patterns we observed across the Neotropical dry forest biome challenge representation of soil processes in ecosystem models.
Self‐Assembled VS4 Hierarchitectures with Enhanced Capacity and Stability for Sodium Storage
Authors: Cheng Siling , Yao Kaitong , Zheng Kunxiong , Li Qifei , Chen Dong , Jiang Yu , Liu Weiling , Feng Yuezhan , Rui Xianhong , Yu Yan
Published: March 2021

Sodium‐ion batteries (SIBs) have become an auspicious candidate for large‐scale energy storage by cause of low cost, natural abundance, and similar working principle with lithium‐ion batteries (LIBs). At present, there is an urgent need to explore superior anode materials with rapid and stable sodiation/desodiation. Herein, 3D self‐assembled VS4 curly nanosheets hierarchitectures (VS4‐CN‐Hs) are developed for SIB anodes, where VS4 possesses a large theoretical sodium storage capacity, and the building block of nanosheets has large exposed surface area to the electrolyte as well as the constructed hierarchitectures can provide abundant buffer space to alleviate the volume expansion. As a result, VS4‐CN‐Hs anode possesses excellent electrochemical performance under a wide voltage window of 0.01–3.0 V, such as high reversible capacity of 863 mA h g−1 at 0.1 A g−1, marvelous rate feature (444 mA h g−1 at 10 A g−1), and extralong cycle stability (386 mA h g−1 after 1000 times at 5 A g−1).
CD4+ T cells regulate glucose homeostasis independent of adipose tissue dysfunction in mice
Authors: Brinker Georg , Froeba Janine , Arndt Lilli , Braune Julia , Hobusch Constance , Lindhorst Andreas , Bechmann Ingo , Gericke Martin
Published: March 2021

Obesity is frequently associated with a chronic low‐grade inflammation in the adipose tissue (AT) and impaired glucose homeostasis. Adipose tissue macrophages (ATMs) have been shown to accumulate in the inflamed AT either by means of recruitment from the blood or local proliferation. ATM proliferation and activation can be stimulated by TH2 cytokines, such as IL‐4 and IL‐13, suggesting involvement of CD4‐positive T cells in ATM proliferation and activation. Furthermore, several studies have associated T cells to alterations in glucose metabolism. Therefore, we sought to examine a direct impact of CD4‐positive T cells on ATM activation, ATM proliferation and glucose homeostasis using an in vivo depletion model. Surprisingly, CD4 depletion did not affect ATM activation, ATM proliferation, or insulin sensitivity. However, CD4 depletion led to a significant improvement of glucose tolerance. In line with this, we found moderate disturbances in pancreatic endocrine function following CD4 depletion. Hence, our data suggest that the effect on glucose metabolism observed after CD4 depletion might be mediated by organs other than AT and independent of AT inflammation.
Evaluating the suppression effectiveness of hybrid nitrogen and water mist with a cup burner coflowing flame
Authors: Ni Xiaomin , Zheng Zhong , Li Guochun , Wang Xishi
Published: March 2021

The suppression effectiveness of an intrinsically clean hybrid fire suppressant consisting of nitrogen and water mist was experimentally studied by a cup burner method with methane/air coflowing flame. A series of hybrid agents with different weight ratios of nitrogen and water mist (Sauter mean diameter: 12.6 μm) were tested and compared with nitrogen and water mist used alone. The minimum mass‐based extinction concentration (MEC) of neat nitrogen and water mist was measured as 32.1% and 15.2%, respectively. When combined, MEC of the hybrid agents fell between the limiting values of nitrogen and water mist used alone. An approximately linear relationship was shown for the suppression behavior of nitrogen and water mist in combination. The flow field of suppressants during the flame suppression process was studied by particle imaging velocimetry (PIV) technique. A small portion of water droplets near the flame front evaporated, which contributed to flame extinction by heat absorption and oxygen dilution. The remaining bulk mist was entrained vertically with the air flow, showing little effect on the flame base.
Proton exchange membrane fuel cell degradation model based on catalyst transformation theory
Authors: Ao Yunjin , Chen Kui , Laghrouche Salah , Depernet Daniel
Published: March 2021

Durability is a severe problem in the commercial application of proton exchange membrane fuel cell (PEMFC). The platinum (Pt) catalyst which greatly affects performance and durability is one of the most important components in PEMFC. However, few PEMFC degradation models focused on the Pt catalyst degradation process in molecule scale. In this paper, a novel PEMFC catalyst degradation model is developed based on the catalyst transformation theory. In this model, the Pt catalyst degrades by changing form and size according to the transformation theory, which includes Pt dissolution and Ostwald ripening mechanisms. The advantage of this new model is that the transformation of every Pt particle is calculated directly, and the characteristics of every particle are considered, thus it can give more accurate catalyst degradation process. Six groups of experimental data have been used to validate the effectiveness of the proposed degradation model of PEMFC. Furthermore, the accuracy of the proposed degradation model is superior to a traditional model, and the application of such a degradation model to the performance prediction of the PEMFC has been discussed.
Solving the Opioid Crisis Isn't Just a Public Health Challenge—It's a Bioethics Challenge
Authors: Rieder Travis N.
Published: March 2021

Among those who discuss America's opioid crisis, it is popular to claim that we know what we, as a society, ought to do to solve the problem—we simply don't want it badly enough. We don't lack knowledge; we lack the will to act and to fund the right policies. In fact, I've heard two versions of this. Among those who focus on prescription opioids, it is clear that we ought to stop prescribing so many powerful opioid painkillers. And among my public health colleagues focusing on illicit drug use, it is clear that we ought to expand addiction treatment and harm‐reduction services. The problem, however, is that the second claim is not obvious (and, indeed, is denied by many Americans), and the first claim probably isn't even true (at least, not in so crude a form). In short, the opioid crisis presents not only a problem of political will but also one of ethics. It will take work to discover or justify our normative claims in this arena.
The Golden Rule
Authors: Sauder Ryan
Published: March 2021

The Hastings Center's chief advancement officer describes values and intellectual interests that undergird his work. “My job is itself collaborative in spirit,” Sauder writes. “My primary responsibility is to identify and build connections with a wide variety of people who value ethical decision‐making at the crossroads of health, science, and technology.”
A Man of Vision: Daniel Callahan on the Nasty Problem and the Noxious Brew
Authors: Marshall Mary Faith
Published: March 2021

This essay, published shortly before the 2020 U.S. presidential election (mired in controversy over a potential judicial appointment to the Supreme Court), celebrates Daniel Callahan's prescient bookAbortion: Law, Choice and Morality.Nothing could be timelier. Callahan's central question was the “moral and social” struggle requisite for coherent policies and laws regulating abortion. He rejected “one‐value” positions and strove to develop an expansive middle ground. He decried emotion untutored by reason, crude polemics, and bludgeoning: his recipe for a “noxious brew.” Callahan's way of thinking preceded the development of a critical health humanities, the advent of moral foundations theory in psychology, and the philosophical concept of a moral imagination. Each of these inheres in his rigorous approach to the abortion problem. His honesty and humility led to a sea change in his position on abortion. Fifty years later, much can still be learned from Callahan's arguments—about abortion and other bioethics issues—most importantly, in how we address wider social issues in these polarized times.
Between Crisis and Convention: How Should We Address Contingency?
Authors: Bibler Trevor
Published: March 2021

The Covid‐19 pandemic has brought about renewed conversation about equality and equity in the distribution of medical resources. Much of the recent conversation has focused on creating and implementing policies in times of crisis when resources are exhausted. Depending on how the pandemic develops, some communities may implement crisis measures, but many health care facilities are currently experiencing shortages of staff and materials even if the facilities have not implemented crisis standards. There is a need for shared conversation about equality and equity in these times of contingency between conventional and crisis medicine. To respond well to these challenges, I recommend that institutions rely on policy, professional education, and ethics consultation. As is the case with crisis policies, creating contingency policies requires that health care professionals decide on how, specifically, to achieve equity. A policy is only as effective as its implementation; therefore, institutions should invest in context‐specific education on contingency policies. Finally, ethics consultation should be available for questions that contingency policies cannot address.
Genetic Data Aren't So Special: Causes and Implications of Reidentification
Authors: Kasperbauer T.J. , Schwartz Peter H.
Published: March 2021

Genetic information is widely thought to pose unique risks of reidentifying individuals. Genetic data reveals a great deal about who we are and, the standard view holds, should consequently be treated differently from other types of data. Contrary to this view, we argue that the dangers of reidentification for genetic and nongenetic data—including health, financial, and consumer information—are more similar than has been recognized. Before different requirements are imposed around sharing genetic information, proponents of the standard view must show that they are in fact necessary. We further argue that the similarities between genetic and nongenetic information have important implications for communicating risks during consent for health care and research. While patients and research participants need to be more aware of pervasive data‐sharing practices, consent forms are the wrong place to provide this education. Instead, health systems should engage with patients throughout patient care to educate them about data‐sharing practices.
Can We Do without Respect and Justice in Animal Research Ethics?
Authors: Walker Rebecca L.
Published: March 2021

This book review essay discusses Principles of Animal Research Ethics (2020), by Tom L. Beauchamp and David DeGrazia.
Heart and Soul
Authors: Kaebnick Gregory E.
Published: March 2021

The lead article in this January‐February 2021 issue—the first of the Hastings Center Report's fiftieth year of publication—does not set out to change medicine. It tries instead to understand it. In “A Heart without Life: Artificial Organs and the Lived Body,” Mary Jean Walker draws on work in phenomenology and on empirical research with people who have received artificial heart devices to argue that such devices may have two very different effects on how a patient experiences the body and the self. Several other pieces in this issue address the ongoing slew of patient care and health policy problems surrounding the Covid‐19 pandemic, and a special report titled Democracy in Crisis: Civic Learning and the Reconstruction of Common Purpose considers the requirements for public involvement in policy‐making about bioethical issues.
Weighted Lotteries and the Allocation of Scarce Medications for Covid‐19
Authors: Jansen Lynn A. , Wall Steven
Published: March 2021

The allocation of vaccines and therapeutics for Covid‐19 obviously raises ethical questions, and physicians and ethicists have begun to address them. Writers have identified various criteria that should guide allocation decisions, but the criteria often conflict and need to be balanced against one another. This article proposes a model for thinking about how different considerations that are relevant to the distribution of vaccines and scarce treatments for Covid‐19 could be integrated into an allocation procedure. The model employs the construct of a weighted lottery, which is a construct that has been employed in other contexts that involve the distribution of scarce resources. The article highlights the advantages of applying a weighted lottery to the Covid‐19 context and offers an illustration for how it might work in practice. The primary aim of the article is to articulate the structural features of a weighted lottery for this context and to bring out its advantages over other methods for allocating Covid‐19 medications.
Selective attention modulates neural envelope tracking of informationally masked speech in healthy older adults
Authors: Kurthen Ira , Galbier Jolanda , Jagoda Laura , Neuschwander Pia , Giroud Nathalie , Meyer Martin
Published: March 2021

Speech understanding in noisy situations is compromised in old age. This study investigated the energetic and informational masking components of multi‐talker babble noise and their influence on neural tracking of the speech envelope in a sample of healthy older adults. Twenty‐three older adults (age range 65–80 years) listened to an audiobook embedded in noise while their electroencephalogram (EEG) was recorded. Energetic masking was manipulated by varying the signal‐to‐noise ratio (SNR) between target speech and background talkers and informational masking was manipulated by varying the number of background talkers. Neural envelope tracking was measured by calculating temporal response functions (TRFs) between speech envelope and EEG. Number of background talkers, but not SNR modulated the amplitude of an earlier (around 50 ms time lag) and a later (around 300 ms time lag) peak in the TRFs. Selective attention, but not working memory or peripheral hearing additionally modulated the amplitude of the later TRF peak. Finally, amplitude of the later TRF peak was positively related to accuracy in the comprehension task. The results suggest that stronger envelope tracking is beneficial for speech‐in‐noise understanding and that selective attention is an important ability supporting speech‐in‐noise understanding in multi‐talker scenes.
Symmetry analysis of MHD Casson fluid flow for heat and mass transfer near a stagnation point over a linearly stretching sheet with variable viscosity and thermal conductivity
Authors: Nazim Tufail Muhammad , Zaib Faryal
Published: March 2021

In this article, the impacts of variable viscosity and thermal conductivity on magnetohydrodynamic, heat transfer, and mass transfer flow of a Casson fluid are analyzed on a linearly stretching sheet inserted in a permeable medium along with heat source/sink and viscous dissipation. To reduce the ascendant partial differential equations into ordinary differential equations, Lie group transformation is utilized. Further, the fourth‐order Runge–Kutta strategy is utilized to solve the ordinary differential equations numerically. The numerical results obtained for various parameters by employing coding in MATLAB programming are investigated and considered through graphical representation and tables. We anatomize the impacts of distinctive parameters on velocity, temperature, and concentration distributions.
Responses to global financial standards in emerging markets: Regulatory neoliberalism and the BaselIICapital Accord
Authors: Alvi Farzad Haider , Williamson Peter J.
Published: March 2021

This paper examines the diffusion of the Basel II Capital Accord into emerging markets (EMs). The literature on the diffusion of financial standards reinforces determinism: carefully derived standards such as those around financial liberalization are assumed to be applicable to all markets in an effort to promote stability and international harmonization. Attempts to use financial liberalization and macroprudential toolkits such as Basel II, however well intentioned, can increase rather than mitigate financial instability, due in part to unevenness in the adoption of financial standards. We analyse rich, action research data on the response of banks in 19 EMs in Asia, the Middle East, and Eastern Europe to the advent of Basel II. We find heterogeneous rather than universalistic responses, captured as four types of behavioural variations leading to differences in the intensity of diffusion: Reformist, Instigative, Disobliging and Cosmetic. The variations reflect regulatory neoliberalism. The typology contributes to our understanding of the interaction between bank behaviour, regulator stance and institutional context as determinants of the diffusion of global financial standards.
Performance evaluation of bactericidal effect and endotoxin inactivation by low‐temperature ozone/hydrogen peroxide mixed gas exposure
Authors: Nomura Yusuke , Yamamura Junji , Fukui Chie , Fujimaki Hideo , Sakamoto Kazuyuki , Matsuo Ken‐ichi , Kuromatsu Hisashi , Kikuchi Yutaka , Haishima Yuji
Published: March 2021

This study evaluated the performance of a new O3/H2O2 mixed gas sterilization instrument for killing microorganisms and inactivating bacterial endotoxin at low temperatures. Sterility assurance level was achieved by an over 6‐log reduction of Geobacillus stearothermophilus ATCC 12980, and the decimal reduction value was 0.77 min in sterilization mode. A reduction of over 3 logs in Limulus amebocyte lysate coagulation activity of purified endotoxin from Escherichia coli was observed after treatment in endotoxin‐inactivation mode. The same inactivation ability was observed when treating dried bacterial cells. Biomaterials made of polymer or metal did not exhibit cytotoxicity after gas exposure at O3 concentrations below 200 ppm. As the results of human cell‐based pyrogen testing, significant amounts of endotoxin that were over the limit for medical devices contacting cerebrospinal fluid (2.15 EU/device) were detected on scissors washed with a washer‐disinfector and sterilized with ethylene oxide or autoclaving. In contrast, endotoxin decreased to 0.29 ± 0.05 EU/device after O3/H2O2 mixed gas sterilization in endotoxin‐inactivation mode. Compared to conventional gas sterilization methods, O3/H2O2 mixed gas has high sterilization ability and a strong capacity to inactivate endotoxin. It is expected that this sterilization technology will improve the safety of reusable medical devices and utensils for regenerative medicine.
Reduction of Calciprotein Particles in Adults Receiving Infliximab for Chronic Inflammatory Disease
Authors: Tiong Mark K , Smith Edward R , Toussaint Nigel D , Al‐Khayyat Hasan F , Holt Stephen G
Published: March 2021

Patients with chronic inflammatory diseases (CID) experience accelerated loss of bone mineral density, which is often accompanied by increased vascular calcification. These disturbances can be attenuated by therapies for inflammation, such as the tumor necrosis factor inhibitor infliximab. Calciprotein particles (CPP) are circulating colloidal aggregates of calcium and phosphate together with the mineral‐binding protein fetuin‐A, which have emerged as potential mediators of vascular calcification. The precise origins of serum CPP are unclear, but bone turnover may be an important source. In this longitudinal observational study, we studied patients with CID undergoing treatment with infliximab to assess the temporal relationship between bone turnover and circulating CPP. Ten patients with active CID receiving infliximab induction therapy and an additional 3 patients with quiescent CID on maintenance infliximab therapy were studied for 8 weeks with repeated measures of bone turnover markers as well as CPP (calciprotein monomers [CPM], primary CPP [CPP‐I], and secondary CPP [CPP‐II]). Therapeutic response was appraised using validated disease activity scores. At baseline, those with active CID had elevated markers of bone resorption and suppressed bone formation markers as well as higher CPM and CPP‐I compared with those with quiescent CID. In responders, there was an early but transient reduction in resorption markers by week 1, but a more sustained increase in bone formation markers compared with non‐responders at week 8. This was accompanied by reductions in CPM (β = −6.5 × 103 AU [95% CI −11.1, −1.8], p = 0.006) and CPP‐I (β = −23.4 × 104 particles/mL [95% CI −34.8, −11.9], p < 0.001). In contrast, no significant changes in any markers were observed in non‐responders or those receiving maintenance therapy. Thus, CPP have a dynamic association with changes in bone turnover in response to infliximab therapy, adding to accumulating evidence of the role of bone as a determinant of systemic levels. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
Placental neurotrophin levels in gestational diabetes mellitus
Authors: Jadhav Anjali , Khaire Amrita , Gundu Shridevi , Wadhwani Nisha , Chandhiok Nomita , Gupte Sanjay , Joshi Sadhana
Published: March 2021

Objective

Neurotrophins are known to influence the development and maturation of the feto‐placental unit and affect fetal growth trajectories. This study reports the levels of nerve growth factor (NGF) and brain‐derived growth factor (BDNF) in the placenta of women with gestational diabetes mellitus (GDM).

Methods

A total number of 60 women with GDM and 70 women without GDM (non‐GDM) were included in the study. Placental NGF and BDNF levels were measured using commercially available ELISA kits.

Results

Placental NGF levels were lower (p < .05) in women with GDM compared to non‐GDM women. Maternal body mass index (BMI), mode of delivery, and the gender of the baby influenced the placental NGF levels. Placental BDNF levels were similar in GDM and non‐GDM women. There was an influence of baby gender on the placental BDNF levels while maternal BMI and mode of delivery did not show any effect. In regression models adjusted for maternal age at delivery, gestational age, maternal BMI, mode of delivery, and baby gender, the placental NGF levels in the GDM group were lower (−0.144 pg/ml [95% CI −0.273, 22120.016] p = .028) as compared to the non‐GDM group. However, there was no difference in the BDNF levels between the groups.

Conclusion

This study for the first time demonstrates differential effects on neurotrophic factors such as BDNF and NGF in the placenta in pregnancies complicated by GDM. Alterations in the levels of placental neurotrophins in GDM deliveries may affect placental development and fetal brain growth. This has implications for increased risk for neurodevelopmental pathologies in later life.