bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Strontium Ions on Crystallization of Amorphous Calcium Carbonate
Authors: Schmidt Ingo , Zolotoyabko Emil , Lee Kyubock , Gjardy André , Berner Alex , Lakin Evgeny , Fratzl Peter , Wagermaier Wolfgang
Published: April 2019

In biomineralization, amorphous precursors enable formation of complicated crystal shapes and incorporation of organic and inorganic impurities. In some cases the concentrations of the inorganic impurity atoms greatly exceed the thermodynamical (equilibrium) solubility limits. To shed additional light on this, crystallization experiments with Sr‐rich amorphous calcium carbonate (ACC) are carried out. The Sr‐concentration in ACC, Sr/(Ca+Sr) ≈0.3, is more than 60 times larger than its solubility limit in calcite. Crystallization of ACC is accomplished using two different pathways: i) in a high humidity environment at room temperature, and ii) upon heating at 300 °C. In both cases, X‐ray diffraction measurements revealed the formation of particular crystal phases with an ability to take up substantial amounts of Sr. Crystals formed via the humidity route comprised spatially separated regions of almost pure rhombohedral calcite and orthorhombic aragonite/strontianite solid solution with a Sr/(Ca+Sr) ratio equal nearly 0.5. Crystallization of ACC upon heating resulted in the appearance of a new calcite‐like phase with reduced space symmetry, , instead of for regular calcite. Symmetry reduction in this Sr‐rich ‐phase is due to the rotational disorder of flat carbonate groups about the c‐axis, which is responsible for the enhanced lattice capacity of Sr incorporation.
A Multiphase Protocol for Selective Hydrogenation and Reductive Amination of Levulinic Acid with Integrated Catalyst Recovery
Authors: Bellè Alessandro , Tabanelli Tommaso , Fiorani Giulia , Perosa Alvise , Cavani Fabrizio , Selva Maurizio
Published: April 2019

At 60–150 °C and 15–35 bar H2, two model reactions of levulinic acid (LA), hydrogenation and reductive amination with cyclohexylamine, were explored in a multiphase system composed of an aqueous solution of reactants, a hydrocarbon, and commercial 5 % Ru/C as a heterogeneous catalyst. By tuning the relative volume of the immiscible water/hydrocarbon phases and the concentration of the aqueous solution, a quantitative conversion of LA was achieved with formation of γ‐valerolactone orN‐(cyclohexylmethyl)pyrrolidone in >95 and 88 % selectivity, respectively. Additionally, the catalyst could be segregated in the hydrocarbon phase and recycled in an effective semi‐continuous protocol. Under such conditions, formic acid additive affected the reactivity of LA through a competitive adsorption on the catalyst surface. This effect was crucial to improve selectivity for the reductive amination process. The comparison of 5 % Ru/C with a series of carbon supports demonstrated that the segregation phenomenon in the hydrocarbon phase, never previously reported, was pH‐dependent and effective for samples displaying a moderate surface acidity.
GNrep mouse: A reporter mouse for front–rear cell polarity
Authors: Barbacena Pedro , Ouarné Marie , Haigh Jody J. , Vasconcelos Francisca F. , Pezzarossa Anna , Franco Claudio A.
Published: April 2019

Cell migration is essential during development, regeneration, homeostasis, and disease. Depending on the microenvironment, cells use different mechanisms to migrate. Yet, all modes of migration require the establishment of an intracellular front–rear polarity axis for directional movement. Although front–rear polarity can be easily identified in in vitro conditions, its assessment in vivo by live‐imaging is challenging due to tissue complexity and lack of reliable markers. Here, we describe a novel and unique double fluorescent reporter mouse line to study front–rear cell polarity in living tissues, called GNrep. This mouse line simultaneously labels Golgi complexes and nuclei allowing the assignment of a nucleus‐to‐Golgi axis to each cell, which functions as a readout for cell front–rear polarity. As a proof‐of‐principle, we validated the efficiency of the GNrep line using an endothelial‐specific Cre mouse line. We show that the GNrep labels the nucleus and the Golgi apparatus of endothelial cells with very high efficiency and high specificity. Importantly, the features of fluorescent intensity and localization for both mCherry and eGFP fluorescent intensity and localization allow automated segmentation and assignment of polarity vectors in complex tissues, making GNrep a great tool to study cell behavior in large‐scale automated analyses. Altogether, the GNrep mouse line, in combination with different Cre recombinase lines, is a novel and unique tool to study of front–rear polarity in mice, both in fixed tissues or in intravital live imaging. This new line will be instrumental to understand cell migration and polarity in development, homeostasis, and disease.
Sequestration and biosynthesis of cyanogenic glucosides in passion vine butterflies and consequences for the diversification of their host plants
Authors: Pinheiro de Castro Érika C. , Zagrobelny Mika , Zurano Juan Pablo , Zikan Cardoso Márcio , Feyereisen René , Bak Søren
Published: April 2019

The colorful heliconiine butterflies are distasteful to predators due to their content of defense compounds called cyanogenic glucosides (CNglcs), which they biosynthesize from aliphatic amino acids. Heliconiine larvae feed exclusively on Passiflora plants where ~30 kinds of CNglcs have been reported. Among them, some CNglcs derived from cyclopentenyl glycine can be sequestered by some Heliconius species. In order to understand the evolution of biosynthesis and sequestration of CNglcs in these butterflies and its consequences for their arms race with Passiflora plants, we analyzed the CNglc distribution in selected heliconiine and Passiflora species. Sequestration of cyclopentenyl CNglcs is not an exclusive trait of Heliconius, since these compounds were present in other heliconiines such as Philaethria, Dryas and Agraulis, and in more distantly related genera Cethosia and Euptoieta. Thus, it is likely that the ability to sequester cyclopentenyl CNglcs arose in an ancestor of the Heliconiinae subfamily. Biosynthesis of aliphatic CNglcs is widespread in these butterflies, although some species from the sara‐sapho group seem to have lost this ability. The CNglc distribution within Passiflora suggests that they might have diversified their cyanogenic profile to escape heliconiine herbivory. This systematic analysis improves our understanding on the evolution of cyanogenesis in the heliconiine–Passiflora system.
Embolism recovery strategies and nocturnal water loss across species influenced by biogeographic origin
Authors: Zeppel Melanie J. B. , Anderegg William R. L. , Adams Henry D. , Hudson Patrick , Cook Alicia , Rumman Rizwana , Eamus Derek , Tissue David T. , Pacala Stephen W.
Published: April 2019

Drought‐induced tree mortality is expected to increase in future climates with the potential for significant consequences to global carbon, water, and energy cycles. Xylem embolism can accumulate to lethal levels during drought, but species that can refill embolized xylem and recover hydraulic function may be able to avoid mortality. Yet the potential controls of embolism recovery, including cross‐biome patterns and plant traits such as nonstructural carbohydrates (NSCs), hydraulic traits, and nocturnal stomatal conductance, are unknown. We exposed eight plant species, originating from mesic (tropical and temperate) and semi‐arid environments, to drought under ambient and elevated CO2 levels, and assessed recovery from embolism following rewatering. We found a positive association between xylem recovery and NSCs, and, surprisingly, a positive relationship between xylem recovery and nocturnal stomatal conductance. Arid‐zone species exhibited greater embolism recovery than mesic zone species. Our results indicate that nighttime stomatal conductance often assumed to be a wasteful use of water, may in fact be a key part of plant drought responses, and contribute to drought survival. Findings suggested distinct biome‐specific responses that partially depended on species climate‐of‐origin precipitation or aridity index, which allowed some species to recover from xylem embolism. These findings provide improved understanding required to predict the response of diverse plant communities to drought. Our results provide a framework for predicting future vegetation shifts in response to climate change.
Life history strategies drive size‐dependent biomass allocation patterns of dryland ephemerals and shrubs
Authors: Chen Renfei , Ran Jinzhi , Huang Heng , Dong Longwei , Sun Yuan , Ji Mingfei , Hu Weigang , Yao Shuran , Lu Jingli , Gong Haiyang , Xie Shubin , Du Qiajun , Hou Qingqing , Niklas Karl J. , Deng Jianming
Published: April 2019

Plant biomass allocation patterns are important to understanding and predicting ecosystem carbon cycles and other important ecological processes. Consequently, many attempts have been made to study these patterns. However, most studies focus on data from species in temperate forests to the neglect of data from desert species adapted to arid conditions. We hypothesize that different life history strategies drive or at least participate in different plant biomass allocation patterns, as, for example, the life history differences between desert ephemeral and shrub species. We tested this hypothesis using field data gathered directly from the entire desert vegetation in Northwestern China. When the data from each of the two species groups are pooled, ephemeral and shrub species manifest different scaling relationships between above‐ and belowground biomass, unlike the isometric scaling relationships typically reported for forest tree species. The observed scaling relationships are sensitive to water stress and temperature gradients. The scaling exponents numerically decrease with increasing drought stress, and relatively more biomass is allocated to shoot growth in ephemeral species (presumably to rapidly complete their life history). In the case of shrubs, the numerical value of the scaling exponent is insensitive to rainfall, presumably because these species allocate more biomass to root growth to access belowground water. However, the scaling exponent is significantly sensitive to temperature, which also regulates root growth. Moreover, for the two species groups, root–shoot ratios are jointly regulated by precipitation and temperature. The different biomass allocation patterns appear to result from different life histories that maximize either competition among neighboring plants, or escaping damage from drought and low temperatures. These findings show how overall body size and life histories jointly regulate biomass allocation patterns under different extreme conditions and provide insights into estimating the dry carbon content in dryland ecosystems.
Downstream transport and seasonal variation in freshwater pearl mussel (Margaritifera margaritifera) eDNA concentration
Authors: Wacker Sebastian , Fossøy Frode , Larsen Bjørn Mejdell , Brandsegg Hege , Sivertsgård Rolf , Karlsson Sten
Published: April 2019

Environmental DNA (eDNA) can be used to detect the presence and abundance of aquatic organisms from water samples. Before implementing this methodology as a tool for monitoring, more knowledge is needed on variation in eDNA concentrations in relation to species abundance and potential confounding factors. Shedding and decay of eDNA may vary extensively over the season and are dependent on environmental factors such as water temperature and on biological processes such as activity level and reproduction. In lotic systems, eDNA concentrations are also affected by downstream transport of eDNA. Sessile freshwater mussels provide an ideal study system for investigating the relationship between species spatial distribution and eDNA concentrations in lotic systems. We quantified freshwater pearl mussel (Margaritifera margaritifera) eDNA concentrations at four localities in a natural river with detailed knowledge of mussel spatial distribution: (a) upstream of the known species distribution, just downstream (b) a small and (c) a large aggregation and (d) 1,700 m downstream of the large aggregation. To study seasonal variation, we quantified eDNA concentrations during three periods: (a) in late spring, with cold water and relatively inactive mussels; (b) in mid‐summer, with higher water temperature and active mussel filtration; and (c) in late summer, during the release of larvae. Species detection was highly reliable, with no detection of eDNA upstream of the species distribution and complete detection downstream of the large aggregation. Detection success of the small aggregation was low, with 13% of the samples testing positive. Downstream transport was efficient, with no significant decrease in eDNA concentrations over 1,700 m river distance. Seasonal variation was strong, with a 20‐fold increase in eDNA concentrations from late spring to late summer, during reproduction. Our results highlight both the potential and challenges of eDNA monitoring in lotic systems.
Regulation of gamma‐frequency oscillation by feedforward inhibition: A computational modeling study
Authors: Rennó‐Costa César , Teixeira Daniel Garcia , Soltesz Ivan
Published: April 2019

Throughout the brain, reciprocally connected excitatory and inhibitory neurons interact to produce gamma‐frequency oscillations. The emergent gamma rhythm synchronizes local neural activity and helps to select which cells should fire in each cycle. We previously found that such excitation‐inhibition microcircuits, however, have a potentially significant caveat: the frequency of the gamma oscillation and the level of selection (i.e., the percentage of cells that are allowed to fire) vary with the magnitude of the input signal. In networks with varying levels of brain activity, such a feature may produce undesirable instability on the time and spatial structure of the neural signal with a potential for adversely impacting important neural processing mechanisms. Here we propose that feedforward inhibition solves the latter instability problem of the excitation‐inhibition microcircuit. Using computer simulations, we show that the feedforward inhibitory signal reduces the dependence of both the frequency of population oscillation and the level of selection on the magnitude of the input excitation. Such a mechanism can produce stable gamma oscillations with its frequency determined only by the properties of the feedforward network, as observed in the hippocampus. As feedforward and feedback inhibition motifs commonly appear together in the brain, we hypothesize that their interaction underlies a robust implementation of general computational principles of neural processing involved in several cognitive tasks, including the formation of cell assemblies and the routing of information between brain areas.
Pharmacokinetic Drug‐Drug Interactions Between Letermovir and the Immunosuppressants Cyclosporine, Tacrolimus, Sirolimus, and Mycophenolate Mofetil
Authors: McCrea Jacqueline B. , Macha Sreeraj , Adedoyin Adedayo , Marshall William , Menzel Karsten , Cho Carolyn R. , Liu Fang , Zhao Tian , Levine Vanessa , Kraft Walter K. , Yoon Esther , Panebianco Deborah , Stoch S. Aubrey , Iwamoto Marian
Published: April 2019

Letermovir (AIC246, MK‐8228) is a human cytomegalovirus terminase inhibitor indicated for the prophylaxis of cytomegalovirus infection and disease in allogeneic hematopoietic stem cell transplant recipients that is also being investigated for use in other transplant settings. Many transplant patients receive immunosuppressant drugs, of which several have narrow therapeutic ranges. There is a potential for the coadministration of letermovir with these agents, and any potential effect on their pharmacokinetics (PK) must be understood. Five phase 1 trials were conducted in 73 healthy female participants to evaluate the effect of letermovir on the PK of cyclosporine, tacrolimus, sirolimus, and mycophenolic acid (active metabolite of mycophenolate mofetil [MMF]), as well as the effect of cyclosporine and MMF on letermovir PK. Safety and tolerability were also assessed. Coadministration of letermovir with cyclosporine, tacrolimus, and sirolimus resulted in 1.7‐, 2.4‐, and 3.4‐fold increases in area under the plasma concentration–time curve and 1.1‐, 1.6‐, and 2.8‐fold increases in maximum plasma concentration, respectively, of the immunosuppressants. Coadministration of letermovir and MMF had no meaningful effect on the PK of mycophenolic acid. Coadministration with cyclosporine increased letermovir area under the plasma concentration–time curve by 2.1‐fold and maximum plasma concentration by 1.5‐fold, while coadministration with MMF did not meaningfully affect the PK of letermovir. Given the increased exposures of cyclosporine, tacrolimus, and sirolimus, frequent monitoring of concentrations should be performed during administration and at discontinuation of letermovir, with dose adjustment as needed. These data support the reduction in clinical dosage of letermovir (to 240 mg) upon coadministration with cyclosporine.
A STING to inflammation and autoimmunity
Authors: Kumar Vijay
Published: April 2019

Various intracellular pattern recognition receptors (PRRs) recognize cytosolic pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). Cyclic GMP-AMP synthase (cGAS), a cytosolic PRR, recognizes cytosolic nucleic acids including dsDNAs. The recognition of dsDNA by cGAS generates cyclic GMP-AMP (GAMP). The cGAMP is then recognized by STING generating type 1 IFNs and NF-κB-mediated generation of pro-inflammatory cytokines and molecules. Thus, cGAS-STING signaling mediated recognition of cytosolic dsDNA causing the induction of type 1 IFNs plays a crucial role in innate immunity against cytosolic pathogens, PAMPs, and DAMPs. The overactivation of this system may lead to the development of autoinflammation and autoimmune diseases. The article opens with the introduction of different PRRs involved in the intracellular recognition of dsDNA and gives a brief introduction of cGAS-STING signaling. The second section briefly describes cGAS as intracellular PRR required to recognize intracellular nucleic acids (dsDNA and CDNs) and the formation of cGAMP. The cGAMP acts as a second messenger to activate STING- and TANK-binding kinase 1-mediated generation of type 1 IFNs and the activation of NF-κB. The third section of the article describes the role of cGAS-STING signaling in the induction of autoinflammation and various autoimmune diseases. The subsequent fourth section describes both chemical compounds developed and the endogenous negative regulators of cGAS-STING signaling required for its regulation. Therapeutic targeting of cGAS-STING signaling could offer new ways to treat inflammatory and autoimmune diseases.
The Benefits of the Learn to Think Program for Preschoolers’ Creativity: An Explorative Study
Authors: Bai Honghong , Duan Haijun , Kroesbergen Evelyn H. , Leseman Paul P. M. , Hu Weiping
Published: April 2019

This paper presents the Learn to Think preschool (LTT‐P) program for promoting creativity in preschoolers and reviews its potential benefits. LTT‐P was designed within the framework of the successful LTT creativity program for older students and both were developed to fit the Chinese education system. To assess the potential benefits of LTT‐P, a quasi‐experimental pretest‐posttest control group study was conducted in a preschool in an urban region in the northwest of China, involving 68 middle level and 87 senior level children. The Lines and Circles subtests of the Torrance Test of Creative Thinking were used to examine the development of children's creativity on the dimensions fluency, originality, and elaboration between pretest and posttest. The results suggest that the LTT‐P program has the potential to promote young children's creative thinking, especially with regard to the aspects of originality and elaboration. The results for fluency are less clear. To the best of our knowledge, LTT‐P is the first program, grounded in a structured learning theory and sound curriculum framework, to support children's creativity development in Chinese early childhood education.
Fire outbreaks in extreme climate years in the State of Rio de Janeiro, Brazil
Authors: de Andrade Caio F. , Duarte João B. , Barbosa Maria Lucia F. , de Andrade Melina D. , de Oliveira Raquel O. , Delgado Rafael C. , Pereira Marcos G. , Batista Tays S. , Teodoro Paulo E.
Published: April 2019

Plant burning in tropical countries is a threat to the environment. It not only damages the local ecology but also affects the economy and society. This work aimed to analyze the meteorological systems, soil attributes, and meteorological variables derived from NCEP‐DOE Reanalysis 2 for 3 years of atypical climatic events (2005, 2010, and 2015); and relate these factors to the occurrence of fire outbreaks in the State of Rio de Janeiro, Brazil. In 2005, a total of 1,085 fire outbreaks were registered in the State, and most of them occurred during the dry season in the soil classes ultisol (542) and oxisol (139). The highest fire outbreaks concentration was reported in 2010, totaling 1, 702 outbreaks, and Argissolo and Latossolo (747 and 301, respectively) were also the most predominant soil classes. This fact can be explained by the greater predominance of pastures and greater area in km2 in the State. In 2015, the highest number of fire outbreaks was recorded, again, in Argissolo (418), in addition to Gleissolo (102). The total number of fire outbreaks registered in 2015 was lower than those recorded in 2005 and 2010, totaling 916 fire outbreaks statewide. The correlation shows maximum positive values of zonal wind component (0.71) for 2005. The highest negative values correlations found for 2005, 2010, and 2015 were for the meteorological traits soil moisture and relative air humidity, respectively. The present study is important for highlighting up the vulnerability of the Atlantic Forest ecosystem, given the occurrence of fire outbreaks.
Ultrasonication‐Induced Modification of Hydroxyapatite Nanoparticles onto a 3D Porous Poly(lactic acid) Scaffold with Improved Mechanical Properties and Biocompatibility
Authors: Si Junhui , Lin Jixin , Su Chen , Yu Shengrui , Cui Zhixiang , Wang Qianting , Chen Wenzhe , Turng Lih‐Sheng
Published: April 2019

A 3D porous poly(lactic acid) (PLA) scaffold with high porosity and well‐connected pores is fabricated using a vacuum‐assisted solvent casting technique. Its surface is modified with hydroxyapatite (HA) nanoparticles using ultrasonication to prepare an HA‐modified PLA/HA scaffold. For reference, an HA‐blended (b‐PLA‐HA) scaffold is fabricated via the solution blending method. The morphology, porosity, hydrophilicity, swelling ratio, mechanical properties, and cell viability of the PLA, b‐PLA‐HA, and PLA/HA scaffolds are systematically studied. The results show that HA nanoparticles are successfully introduced onto the surface of the PLA/HA scaffold, and strong interactions occur between the HA nanoparticles and the PLA matrix. The PLA/HA scaffold still has a high porosity of more than 85% after ultrasonication. The hydrophilicity and mechanical properties of the PLA/HA scaffold are significantly higher than those of the PLA and b‐PLA‐HA scaffolds. Compared with the PLA and b‐PLA‐HA scaffolds, the attachment and growth of mouse embryonic osteoblasts cells (MC3T3‐E1) cultured on the PLA/HA scaffold significantly improve, due to most HA nanoparticles on the surface, resulting in a good and direct interaction between the cells and the scaffold. Therefore, the PLA/HA scaffold possesses great potential to be used as a tissue engineering scaffold.
Analog of the Gellerstedt problem for a loaded equation of the third order
Authors: Baltaeva Umida , Torres Pedro J.
Published: April 2019

In this paper, we study an analog of the Gellerstedt problem for the third‐order loaded equation with boundary conditions on nonparallel characteristics in the hyperbolic domain of the equation.
Combining multiband slice selection with consistent k‐t‐space EPSI for accelerated spectral imaging
Authors: Schmidt Rita , Seginer Amir , Tal Assaf
Published: April 2019

Purpose

To design and implement a multislice MRSI method for fast spectroscopic imaging, using a modified version of echo planar spectroscopic imaging (EPSI) that offers higher spectral width and/or shorter scan time.

Methods

Echo planar spectroscopic imaging suffers from inconsistencies between readout lines acquired with gradients of opposite signs, which has typically been addressed by reconstructing the “positive” and “negative” data sets separately and averaging the two. Nevertheless, consistency between the readout lines of each phase encode can be achieved by interposing the EPSI readouts with alternating “blipped” phase‐encode gradients. This method exchanges inconsistencies along the temporal dimension with inconsistencies along the phase‐encode dimension, which are straightforward to correct, as is conventionally done in various EPI reconstruction schemes. Such consistent k‐t‐space EPSI doubles the spectral width in comparison to EPSI, or, in an alternative realization, yields the same spectral width as EPSI, but at half the acquisition time. In this work, multiband CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration) slice selection was integrated with consistent k‐t‐space EPSI to further accelerate the measurement 2‐fold.

Results

The feasibility of a consistent k‐t‐space EPSI was demonstrated in both phantoms and in vivo brain imaging at 3 T, and four pulse scheme variants were evaluated. It was demonstrated to be useful in optimizing the spectral width and scan acceleration, both of which are limiting factors in vivo. Dual‐band implementation was shown to shorten the duration of the scan 4‐fold.

Conclusion

The consistent k‐t‐space EPSI can be used to accelerate MRSI or, alternatively, double its spectral width. Adding dual‐band CAIPIRINHA further accelerates the acquisition by a factor of 2.
Perspectives on preventing musculoskeletal injuries in nurses: A qualitative study
Authors: Richardson Amy , Gurung Gagan , Derrett Sarah , Harcombe Helen
Published: April 2019

Aims and objectives

To explore the perspectives of nursing and physiotherapy academics regarding techniques designed to prevent musculoskeletal pain and injury in nurses.

Background

High rates of musculoskeletal injuries are evident in nurses, yet there is an absence of research identifying effective interventions to address this problem. Exploring the perspectives of individuals with specialist knowledge in the area could help identify barriers to musculoskeletal injury prevention, and innovative strategies to investigate in future studies.

Design

Cross‐sectional qualitative descriptive study.

Methods

Between October–December 2017, group and individual face‐to‐face semi‐structured interviews were used to collect data. All interviews were audio‐recorded. A thematic analysis was performed, with two researchers coding audio files using NVivo software. The Consolidated Criteria for Reporting Qualitative Research Checklist was consulted to ensure complete reporting of all methods and findings.

Results

Nursing and physiotherapy academics (N = 10) were aware of a range of techniques to prevent musculoskeletal injuries in nurses, including education, equipment, health and safety policy and multi‐disciplinary collaboration. However, several barriers to using these techniques were identified, including age, knowledge and availability of equipment, personal and contextual factors, staffing and time pressures. Several strategies were recommended for further investigation and implementation in clinical practice, such as the sharing of personal experiences, orthopaedic assessments and changes to workplaces that foster a culture of safety.

Conclusions

Further research is required to reduce musculoskeletal pain and injury among nurses. This research should account for the barriers to current prevention strategies and consider investigating novel interventions.

Relevance to clinical practice

These findings highlight strategies for preventing musculoskeletal injuries among nurses that are likely to be most effective in clinical practice.
Numerical approximation of a concrete carbonation model: Study of the ‐law of propagation
Authors: Zurek Antoine
Published: April 2019

In this paper, we are interested in the long time behavior of approximate solutions to a free boundary model which appears in the modeling of concrete carbonation [1]. In particular, we study the long time regime of the moving interface. The numerical solutions are obtained by an implicit in time and finite volume in space scheme. We show the existence of solutions to the scheme and, following [2‐3], we prove that the approximate free boundary increases in time following a‐law. Finally, we supplement the study through numerical experiments.
Microstructure effects on the rheology of nanoclay‐filled PHB/LDPE blends
Authors: Karami Samaneh , Nazockdast Hossein , Ahmadi Zahed , Rabolt John F. , Noda Isao , Chase D. Bruce
Published: April 2019

The rheological and morphological properties of the nanoclay‐filled LDPE/PHB blends using LDPE‐g‐MAH as compatibilizer were determined. SEM data showed that the morphology was more sensitive to organoclay incorporation, compared to inclusion of the compatibilizer. Moreover, the results of image analysis and rheological studies indicated that nanoclay was located in the PHB phase after migrating from the LDPE phase, due to the thermodynamic and viscosity effects. The data obtained also showed that the stabilization mechanisms of PHB and LDPE matrix nanocomposites is due to coalescence prevention (due to the physical barrier) and alteration in the viscosity ratio of the phases, respectively. The obvious, pseudo‐solid‐like behavior over a wide range of frequencies in the PHB/LDPE/nanoclay systems demonstrated that the strong interaction between PHB/LDPE and nanoclay restricted the relaxation process of polymer chains. Therefore, PHB/LDPE/nanoclay was associated with a greater melt strength, which is essential for its favorable processability and applications. POLYM. COMPOS., 40:4125–4134, 2019. © 2019 Society of Plastics Engineers
A novel nanosilica‐supported ultraviolet absorber for the preparation of robust biodegradable plastic film with high ultraviolet aging resistance
Authors: Zhu Shuli , Chen Yongjun , Tang Yuhan , Li Qunyang , Zhong Bangchao , Zeng Xueqi , Xie Dong , Jia Zhixin , Jia Demin
Published: April 2019

A novel type of nanosilica‐supported ultraviolet absorber (SiO2‐N‐0) was successfully prepared by chemically grafting 2,4‐dihydroxybenzophenone (UV‐0) onto the surface of nanosilica (SiO2) with the aid of a coupling agent via a sol–gel method, which was confirmed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. SiO2‐N‐0 was then incorporated into poly(butylene adipate‐co‐terephthalate) (PBAT) to fabricate biodegradable composite film with a casting method. As expected, SiO2‐N‐0 was homogeneously dispersed in PBAT matrix, leading to higher mechanical strength and lower water vapor transmission of PBAT/SiO2‐N‐0 film than those of PBAT/SiO2/UV‐0 film. More importantly, because of its low migration and volatility, SiO2‐N‐0 endowed PBAT film with excellent aging resistance under ultraviolet radiation than did the corresponding low molecular ultraviolet absorber UV‐0. Taken together, these results suggest that thus prepared PBAT/SiO2‐N‐0 composite film may find many applications, especially as biodegradable agricultural mulch film. POLYM. COMPOS., 40:4154–4161, 2019. © 2019 Society of Plastics Engineers
Paranoia and risk of personality disorder in the general population
Authors: Muñoz‐Negro José E. , Prudent Cécile , Gutiérrez Blanca , Cervilla Jorge A.
Published: April 2019

Background

We hypothesized that paranoia is associated with personality disorder (PD) in the general population.

Method

This was a population‐based cross‐sectional survey carried out in Andalusia (Spain) using a representative sample of 4 507 participants. Paranoia was measured using the Green Paranoid Thought Scale, and risk of having a PD was screened using the Standardized Assessment of Personality Abbreviated Scale whilst borderline personality disorder (BPD) was measured with the CEPER‐III Exploratory Interview of Personality disorder. Adjusted Pearsons' correlations between paranoia and PD or BPD were calculated.

Results

Paranoia was associated with the risk of having PD and, more robustly, with BPD. Both associations held true for both personality outcomes (PD and BPD) when tested for two Green Paranoid Thought Scale paranoia subtypes (persecutory and reference) after accounting for the effects of age, sex and child abuse.

Conclusions

Paranoia seems to either augment the risk for, or be part of, PD/BPD. © 2019 John Wiley & Sons, Ltd.
Relation Between Yield Stress and Peierls Stress
Authors: Siu Kai Wing , Ngan Alfonso Hing Wan
Published: April 2019

It is often assumed that the Peierls stress of single dislocations can reflect accurately the macroscopic yield stress. Here, dislocation dynamics simulations show that the yield stress‐to‐Peierls stress (Y/P) ratio remains within a small range of ≈0.3 ± 0.1, over a wide range of initial dislocation density, mobile dislocation fraction, and temperature which affects cross slip. This range of Y/P arises from the typical stress concentration ahead of dislocation pile‐ups. The results explain why Y/P was observed to be around one‐third in previous experiments.
Fetal echocardiographic assessment of cardiovascular impact of prolonged support on EXTrauterine Environment for Neonatal Development (EXTEND) system
Authors: Ozawa K. , Davey M. G. , Tian Z. , Hornick M. A. , Mejaddam A. Y. , McGovern P. E. , Flake A. W. , Rychik J.
Published: April 2019

Objective

EXTrauterine Environment for Neonatal Development (EXTEND) is a system to support ongoing fetal growth and organ development in an extrauterine environment, utilizing a pumpless low‐resistance oxygenator circuit. The aim of this study was to evaluate hemodynamics and cardiac function in fetal sheep sustained on the EXTEND system.

Methods

This was a prospective study of fetal sheep supported for a minimum of 3 weeks on EXTEND. Hemodynamic parameters were assessed weekly and included heart rate, mean arterial pressure (MAP), Doppler‐echocardiography‐derived cardiac output (CO), pulsatility indices (PIs) of the fetal middle cerebral artery (MCA), umbilical artery (UA) and ductus venosus and cardiac function, as assessed by speckle‐tracking‐derived global longitudinal strain and strain rate in the right (RV) and left (LV) ventricles. Parameters were compared at 0 days and 1, 2 and 3 weeks following placement on EXTEND.

Results

Of 10 fetal sheep enrolled, seven survived for 3 weeks and were included in the analysis. Median gestational age at cannulation was 107 (range, 95–109) days. Heart rate decreased and MAP increased significantly, but within acceptable ranges, during the study period. The quantities and relative ratios of right and left CO remained stable within the anticipated physiological range throughout the study period. Vascular tracings and PIs appeared to be similar to those seen normally in the natural in‐utero state, with MCA‐PI being higher than UA‐PI. UA tracings demonstrated maintained abundant diastolic flow despite the absence of placental circulation. In both the RV and LV, strain decreased significantly at 1 and 2 weeks relative to baseline but returned to baseline values by week 3.

Conclusions

The EXTEND mechanical support system replicates natural physiology and creates a stable and sustainable cardiovascular construct that supports growth over a 3‐week period. However, there is a period of depressed contractility within the first week with subsequent improvement by week 3. This may reflect a period of physiological accommodation that warrants further investigation. This study lays the foundation for further exploration as the EXTEND system moves towards human application. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.
Ayn Rand’s Objectivist Ethics Applied to Video Game Business
Authors: Harviainen J. Tuomas , Paavilainen Janne , Koskinen Elina
Published: April 2019

This article analyzes the business ethics of digital games, using Ayn Rand’s philosophy of Objectivism. It identifies different types of monetization options as virtuous or nonvirtuous, based on Rand’s views on rational self-interest. It divides the options into ethical Mover and unethical Looter designs, presents those logics in relation to an illustrative case example, Zynga, and then discusses a view on the role of players in relation to game monetization designs. Through our analysis of monetization options in the context of Objectivist ethics, the article contributes to discussions on game revenue ethics. It also expands the still understudied area of applying Rand’s ethics to business, in the context of a new sector, game development, and business. This research enables ethicists to apply a wider-than-before perspective on virtue ethics to online business, and helps game developers act in a virtuous manner, which provides them with a long-term business advantage.
Religion and behavioral procrastination: Mediating effects of locus of control and content of prayer
Authors: Zarzycka Beata , Liszewski Tomasz , Marzel Marek
Published: April 2019

Religion is a significant predictor of self-regulatory processes. Procrastination has been described as the very essence of self-regulatory failure. In this study, we examined the relationship between religiousness and procrastination, with locus of control and styles of prayer playing mediating roles. These relationships were tested using data from 196 students. We applied the Centrality of Religiosity Scale, Levenson’s Locus of Control Scale, the God Control Scale, the Content of Prayer Scale, and the Behavioral Procrastination Scale. The results showed that: God control fully mediates the effects of ideology and intellect on procrastination; internal control fully mediates the effect of public prayer and religious experience on procrastination; and passive style of prayer was a mediator in the relationship between centrality of religion and procrastination. Our findings suggest that religious people may give up internal control, believing that their matters are in God’s hands. Being subject to God’s power provides them with a replacement form of control, which reduces problems of self-regulation.
ECONOMIC SCENARIO GENERATOR AND PARAMETER UNCERTAINTY: A BAYESIAN APPROACH
Authors: Bégin Jean-François
Published: April 2019

In this article, we study parameter uncertainty and its actuarial implications in the context of economic scenario generators. To account for this additional source of uncertainty in a consistent manner, we cast Wilkie’s four-factor framework into a Bayesian model. The posterior distribution of the model parameters is estimated using Markov chain Monte Carlo methods and is used to perform Bayesian predictions on the future values of the inflation rate, the dividend yield, the dividend index return and the long-term interest rate. According to the US data, parameter uncertainty has a significant impact on the dispersion of the four economic variables of Wilkie’s framework. The impact of such parameter uncertainty is then assessed for a portfolio of annuities: the right tail of the loss distribution is significantly heavier when parameters are assumed random and when this uncertainty is estimated in a consistent manner. The risk measures on the loss variable computed with parameter uncertainty are at least 12% larger than their deterministic counterparts.
Predictive characteristics of methicillin-resistant Staphylococcus aureus nares screening tests for methicillin resistance among S. aureus clinical isolates from hospitalized veterans
Authors: Fox Teresa C. , Thuras Paul , Johnson James R.
Published: April 2019

For patients with possible Staphylococcus aureus infection, providers must decide whether to treat empirically for methicillin-resistant S. aureus (MRSA). Nares MRSA colonization screening tests could inform decisions regarding empiric MRSA-active antibiotic use.1,2
MHD Buoyancy Flow of Nanofluids over an Inclined Plate Immersed in Uniform Porous Medium in the Presence of Solar Radiation
Authors: Rashed Z. Z. , Ahmed S. E. , Sheremet M. A.
Published: April 2019

Free convective flow and heat transfer of nanofluid close to the inclined plate immersed in the porous medium under the effects of uniform magnetic field and solar radiation has been studied. Boundary-layer approach, Boussinesq approximation and two-phase nanofluid model have been used for a formulation of the governing equations taking into account convective-radiative heat exchange with an environment. The local similarity method has been adopted for the analysis of the considered phenomenon. The obtained equations have been solved numerically using MATLAB software. The effects of control characteristics on profiles of velocity, temperature and nanoparticles volume fraction as well as Nusselt number have been studied in detail.
A New Exact Analysis for Anisotropic Conductive Heat Transfer in Truncated Composite Spherical Shells
Authors: Norouzi M. , Rahmani H. , Birjandi A. K
Published: April 2019

In the present paper, a general analytical solution is proposed for anisotropic heat conduction through truncated composite spherical shells. The solution is so important in designing the spherical vessels which are usually used to store the CNG, LNG, LPG and other petroleum condensates. Herein, it is supposed that the fiber angle of composite laminate is in range of zero to 90 degrees. Heat convection with ambient flow, an external heat radiation, and a possible internal heat generation are modeled within the heat transfer equation. The exact solution is derived using the complex finite Fourier transform method. The particular solution of transferred equation is found based on the Green’s function and Sturm-Liouville theories. Finally, an inverse integral transformation is applied to form the final analytical solution in physical space. Defining four materials differing in the value of conductivity coefficient in fiber direction, the effects of used composite material and fiber angle on temperature distribution of the spherical shell are investigated in detail.
Influence of Induced Magnetic Field and Radiation on Free Convective Jeffrey Fluid Flow between two Parallel Porous Plates with Soret and Dufour Effects
Authors: Ojjela Odelu , Raju Adigoppula , Naresh Kumar N.
Published: April 2019

The present article deals with the influence of the induced magnetic field on an unsteady two dimensional incompressible free convective chemically reacting slip flow of Jeffrey fluid between two parallel plates under the influence of the thermal radiation, Soret and Dufour. It is assumed that the flow is generated due to periodic suction/injection and the non-uniform temperature and concentrations are varying periodically with time at the plates. The governing partial differential equations are reduced into nonlinear ordinary differential equations by using similarity transformations and solved by shooting method along with Rung-Kutta 4th order scheme. The results are analyzed for various flows, heat and mass transfer characteristics with respect to various prominent parameters such as the ratio of relaxation to retardation times, Deborah number, magnetic Reynold’s number, Strommer’s number, radiation parameter, chemical reaction parameter, Soret and Dufour numbers in details through graphs and tables. It is observed that the temperature of the fluid is enhanced with Soret and Dufour whereas the concentration is decreased. Also the mass transfer rate of the fluid is enhanced with Strommer’s number, whereas the heat transfer rate decreases with increasing of the Jeffery fluid parameter. The present results have good agreement with published work for Newtonian case.
Tremor Estimation and Removal in Robot-Assisted Surgery Using Lie Groups and EKF
Authors: Rana Rohit , Gaur Prerna , Agarwal Vijyant , Parthasarathy Harish
Published: April 2019

This paper aims at estimating the tremor torque using extended Kalman filter (EKF) applied to a two-link 3-DOF robot with nonlinear dynamics modelled using Lie-group and Lie-algebra theory. Later, it is generalised to d number of links with (d + 1) -DOF. The configuration of each link at any time is described by its rotation relative to the preceding link. Using this formulation, an elegant formula for the kinetic energy of the (d + 1) -DOF system is obtained as a quadratic form in the angular velocities with coefficients being highly nonlinear trigonometric functions of the angles. Properties of the Lie algebra generators and the Lie adjoint map are used to arrive at this expression. Further, the gravitational potential energy and the torque potential energy are expressed as nonlinear trigonometrical functions of the angles using properties of the SO(3) group. The input torque comprises a nonrandom intentional torque component and a highly nonlinear tremor torque component. The tremor torque is modelled as a stochastic differential equation (sde) satisfying Ornstein–Uhlenbeck (OU) process with diffusion and damping coefficients. Further, the tremor is treated as the disturbance. The Euler–Lagrange equations for the angles are derived. These form a system of sdes, and the EKF is used to get a more accurate disturbance estimate than that provided by the usual disturbance observer. The EKF is based on noisy angle measurements and yields as a bonus the angle and angular velocity estimates on a real-time basis. The parameters in the OU process model of the tremor torque, and parameters of the Fourier components of the intentional torque have also been estimated.
Interactions among Locus of Control, Environmental Attitudes and Pro-Environmental Behaviour in China
Authors: Giefer Madeline M , Peterson M Nils , Chen Xiaodong
Published: April 2019

Promoting environmentally conscious behaviour requires an understanding of the complex cognitive mechanisms by which people decide to act environmentally. Research suggests that locus of control (LOC), or the extent to which a person feels his or her own actions can produce broader change, is an important predictor of environmental behaviour; however, little is known about how LOC interacts with other cognitive motivators. This study uses a nationwide survey from China to test whether LOC moderates the effect of environmental attitudes on behaviour. Respondents with external LOC (i.e., those who believe personal actions cannot produce change) reported lower pro-environmental behaviour than those with internal LOC (i.e., those who believe personal actions can produce change). In addition, the influence of environmental attitudes on pro-environmental behaviour was stronger among respondents with external LOC than those with internal LOC. These results support efforts to promote conservation in China by promoting internal LOC and add a novel suggestion that attitude-based messaging is more efficacious among audiences with external LOC.