bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison capacity of collagen hydrogel, mix‐powder and in situ hydroxyapatite/collagen hydrogelscaffolds with and without mesenchymal stem cells and platelet‐rich plasma in regeneration of critical sized bone defect in a rabbit animal model
Authors: Bakhtiarimoghadam Behnam , Shirian Sadegh , Mirzaei Esmaeil , Sharifi Siavash , Karimi Iraj , Gharati Gelavizh , Takallu Sara , Nazari Hassan
Published: May 2021

The aim of this study was to investigate the effect of developed collagen (Co) hydrogel (CH), powder‐mixed hydroxyapatite/collagen (HA/Co) hydrogel and in situ synthesized HA/Co (In/HA/Co) hydrogel with or without mesenchymal stem cell (MSC) and platelet‐rich plasma (PRP) on the regeneration of full‐thickness critical size bone defect in the rabbit animal model. In the first step of this study, the scaffolds were synthesized and characterized using FTIR spectroscopy, X‐ray diffraction, and scanning electron microcopy. In the second step or animal study, the radial bone defects were filled with the synthesized scaffolds with and without MSC and PRP. One hundred sixty one year‐old New Zealand white male rabbits were randomly divided in 16 groups of 10 rabbits including control with bone defect without treatment, In/HA/Co, HA/Co, CH, PRP, MSC, CH + PRP, HA/Co, In/HA/Co + PRP, HA/Co + PRP, CH + MSC, In/HA/Co + MSC, HA/Co + MSC, CH + PRP + MSC, In/HA/Co + PRP + MSC, and HA/Co + PRP + MSC. The created defects were filled using the constructed scaffolds alone or seeded with MSCs, with and without PRP injection. The treatments were assessed using histopathological, immunohistochemical and rediographical analysis on days 14, 28, 42, 56 post‐treatment. The plate‐like HA particles were distributed homogeneously in the in situ HA/Co scaffold compared to the HA/Co scaffold and had a similar structure to bone with carbonated plate‐like HA particles and nanofibrilated Co matrix. In situ HA/Co nanocomposite seeded with MSC and enriched by PRP can accelerate bone regeneration resulted from osteoblastic production of osteocalcin protein. Therefore, in situ HA/Co hydrogel seeded with MSC and PRP can be a new approach for bone tissue engineering.
Selective leaching of scandium and yttrium from red mud induced by hydrothermal treatment
Authors: Liliou Anna‐Maria , Saru Maria‐Liliana , Veksha Andrei , Lisak Grzegorz , Giannis Apostolos
Published: May 2021

BACKGROUND

The red mud (bauxite residue) is a rare earth element (REE) bearing material that should be considered a valuable resource. This research investigated the selective leaching of scandium (Sc) and yttrium (Y) from red mud by agitation leaching, as well as thermal and hydrothermal processing. Material characterization was conducted to shed light on the leaching mechanism for high REE extraction selectivity.

RESULTS

The agitation leaching with HCl, HNO3, and H2SO4 was insufficient for high leaching efficiencies of REEs. The addition of Ethylenediaminetetraacetic acid (EDTA) had a minor influence in the leaching of elements. Two acid combinations (0.27 Μ HCl + 0.2 Μ H2SO4 and 0.27 Μ HCl + 0.2 Μ HNO3) were formulated to optimize the leaching efficiency of REEs under thermal and hydrothermal processing. Thermal processing showed high Y leaching, but the selectivity was low because of considerable Ti and Fe extraction. High REE leaching selectivity was achieved when HCl + HNO3 was used in hydrothermal processing at 180 °C. Material characterization indicated that dense aggregation of particles occurred after hydrothermal processing. The mineral geothite was dissolved and new crystals like potassium calcium silicate were formed.

CONCLUSION

The high selective leaching of Sc and Y during hydrothermal processing was controlled by the extraction and desorption of elements from the material surface. The precipitation of Fe, Ca, and Ti and their re‐crystallization in new minerals have enhanced leaching selectivity. © 2021 Society of Chemical Industry (SCI).
Porcupine/Wntless‐dependent trafficking of the conserved WntA ligand in butterflies
Authors: Hanly Joseph J. , Robertson Erica C. N. , Corning Olaf B. W. H. , Martin Arnaud
Published: May 2021

Wnt ligands are key signaling molecules in animals, but little is known about the evolutionary dynamics and mode of action of the WntA orthologs, which are not present in the vertebrates or in Drosophila. Here we show that the WntA subfamily evolved at the base of the Bilateria + Cnidaria clade, and conserved the thumb region and Ser209 acylation site present in most other Wnts, suggesting WntA requires the core Wnt secretory pathway. WntA proteins are distinguishable from other Wnts by a synapomorphic Iso/Val/Ala216 amino‐acid residue that replaces the otherwise ubiquitous Thr216 position. WntA embryonic expression is conserved between beetles and butterflies, suggesting functionality, but the WntA gene was lost three times within arthropods, in podoplean copepods, in the cyclorrhaphan fly radiation, and in ensiferan crickets and katydids. Finally, CRISPR mosaic knockouts (KOs) of porcupine and wntless phenocopied the pattern‐specific effects of WntA KOs in the wings of Vanessa cardui butterflies. These results highlight the molecular conservation of the WntA protein across invertebrates, and imply it functions as a typical Wnt ligand that is acylated and secreted through the Porcupine/Wntless secretory pathway.
An accurate parameter extraction method for small signal model of CNFET
Authors: Wang Jinye , Liu Jun , Chen Zhanfei , Zhang Tingting
Published: May 2021

A new small‐signal model for carbon nanotube field effect transistor (CNFET) is proposed which incorporates the effect of metallic carbon nanotubes (m‐CNTs). The effect of m‐CNTs is comprehensively modeled by contact resistance between m‐CNTs and source/drain (S/D), which also taken into account a parallel RC circuit composed of Cmts, Cmtd, and non‐linear resistance Rdsm. An analytical method is presented to extract model parameters. The model is validated using multi‐tube (MT) CNFET with eight gate fingers of 400 nm length and 50 μm width each manufactured in a 700 nm technology. Excellent agreement is achieved between measured and simulated S‐parameters in the range over 0.6–10.1 GHz.
Showing one's true colors: Leader Machiavellianism, rules and instrumental climate, and abusive supervision
Authors: De Hoogh Annebel H. B. , Den Hartog Deanne N. , Belschak Frank D.
Published: May 2021

Machiavellian (Mach) leaders' tendency to engage in hostile, abusive behavior is destructive for followers and organizations. Yet previous studies suggest that Machs do not always show negative leader behaviors such as abusive supervision. Drawing on trait activation theory, we propose that the manifestation of Mach trait‐relevant behavior depends upon contextual cues from the psychological work climate. Specifically, we argue that a low rule climate or a high instrumental climate offers relevant cues for Mach trait expression. We find support for our hypotheses in two studies of 219 and 183 leader–follower dyads. Both for a low rule climate and a high instrumental climate, leader Machiavellianism is positively related to leader abusive supervision, which, in turn, is negatively related to subordinate OCB and positively related to subordinate emotional exhaustion. However, when rule climate is high or instrumental climate is low, Mach behavior is not expressed, and thus, there is no indirect effect of leader Machiavellianism on follower OCB and emotional exhaustion through leader abusive supervision. Thus, our study shows that the psychological work climate is critical for the expression of leader Machiavellianism in abusive behavior and the related negative consequences to occur.
Decreasing trends in consecutive‐day tornado events in the United States
Authors: Moore Todd W.
Published: May 2021

Days with many tornadoes in the United States have become more common over time. These days tend to occur in consecutive‐day tornado events, but trends in the characteristics of consecutive‐day tornado events have not been documented. The Mann–Kendall trend test and Theil–Sen slope estimator were used in this study to detect trends and estimate rates of change over time in multiple metrics of consecutive‐day tornado events. Results show that the number of consecutive‐day events, the number of days occurring in consecutive‐day events, and the number of tornadoes occurring in consecutive‐day events have decreased over time. The percentages of annual tornadoes and tornado‐days occurring in consecutive‐day events have also decreased over time. These trends suggest that the percentage of tornadoes occurring on isolated days has, alternatively, increased over time.
Periodontitis activates the NLRP3 inflammasome in serum and saliva
Authors: Isola Gaetano , Polizzi Alessandro , Santonocito Simona , Alibrandi Angela , Williams Ray C.
Published: May 2021

Background

Nod‐like receptor family pyrin domain‐containing protein‐3 (NLRP3) complex inflammasome has potentially been shown to play an important role in the development of periodontitis and diabetes. The objective of this study was to analyze the association between serum and salivary NLRP3 concentrations in patients with periodontitis and type‐II diabetes mellitus (DM) and to evaluate whether this association was influenced by potential confounders.

Methods

: For the present study, a cohort of healthy controls (n = 32), and patients with periodontitis (n = 34), type‐II DM (n = 33), and a combination of periodontitis + type‐II DM (n = 34) were enrolled. Patients were characterized on the basis of their periodontal status and analyzed for demographic characteristics, serum mediators, and for serum and salivary concentrations of NLRP3. A uni‐ and multivariate model was established to analyze whether periodontitis, type‐II DM, and CRP influenced serum and salivary NLRP3 concentrations.

Results

In comparison to type‐II DM patients and healthy controls, patients with periodontitis (serum, P = 0.003; saliva P = 0.012) and periodontitis + type‐II DM (serum, P = 0.028; saliva, P = 0.003) had elevated serum and salivary NLRP3 concentrations. The multivariate regression model showed that periodontitis (P = 0.029) and HDL‐cholesterol (P = 0.012) were significant predictors of serum NLRP3 concentrations whereas periodontitis (P = 0.036) and CRP (P = 0.012) were significant predictors of salivary NLRP3.

Conclusion

The results of the present study showed that periodontitis and periodontitis + type‐II DM patients had higher serum and salivary NLRP3 concentrations in comparison to healthy controls and patients with type‐II DM. Periodontitis was demonstrated to be a significant predictor of both serum and salivary NLRP3 concentrations.
Sensitivity of tidal marshes as recorders of major megathrust earthquakes: constraints from the 25 December 2016 Mw 7.6 Chiloé earthquake, Chile
Authors: Brader Martin , Garrett Ed , Melnick Daniel , Shennan Ian
Published: May 2021

We present evidence of land‐level change resulting from the 2016 Mw 7.6 Chiloé earthquake from tidal wetlands along the southern coastline of Isla de Chiloé, Chile, to test criteria for the detection of low‐level, <0.1 m, coseismic land‐level change. In order to record coseismic land‐level change in tidal wetland sediments, both the creation and preservation thresholds must be exceeded. High‐resolution diatom analyses of sediment blocks at two tidal marshes reveal that the 2016 earthquake exceeded the creation threshold and a statistically significant change in diatom assemblage is recorded. In contrast, the preservation threshold was not exceeded and the record of coseismic land‐level motion is not preserved at any location visited. After nine months, interseismic and coseismic changes are statistically indistinguishable. The most sensitive part of the tidal wetland is not consistent between research locations, possibly as a result of changes in sedimentation after the earthquake. We compare records of change from great earthquakes in Alaska with the record from the Chiloé earthquake to explore the detection limit. We propose that coastal palaeoseismological records are highly likely to underestimate the frequency of major (Mw 7–8) earthquakes, with important implications for recurrence intervals and assessment of future seismic hazards.
Vibrational study of lead bromide perovskite materials with variable cations based on Raman spectroscopy and density functional theory
Authors: Ghosh Supriya , Rana Debkumar , Pradhan Bapi , Donfack Patrice , Hofkens Johan , Materny Arnulf
Published: May 2021

Metal halide‐based perovskite semiconductors exhibit excellent optoelectronic properties such as a sharp absorption edge, high absorption coefficients, and a small recombination rate. Mixed compositions result in a variation of the structure of these perovskite materials, which also influences their electronic properties. Even though huge progress in synthesis and device fabrication has been made, still systematic investigations of structural properties of lead halide‐based perovskites are missing. Here, we systematically investigate the vibrational features of lead bromide‐based perovskites using Raman spectroscopy and density functional theory (DFT). We have performed these investigations using MA+, FA+, and Cs+ as cations in the lead bromide structures and determined the vibrational modes both from Raman experiments and DFT simulations. We find a clear dependence of the Raman band wavenumbers on the chosen cations. The structural differences are reflected in the different line‐width broadening of Raman bands, charge distribution on the cations and the extent of their interactions with the bromide anions.
Mitigating the Effects of Acute Vocal Exertion in Individuals With Vocal Fatigue
Authors: Fujiki Robert Brinton , Huber Jessica E. , Sivasankar M. Preeti
Published: May 2021

Objectives/Hypothesis

To investigate the effects of acute vocal exertion on individuals with vocal fatigue and to determine whether semi‐occluded vocal tract exercises (SOVTEs) are more effective than vocal rest in mitigating acute effects.

Study Design

Prospective, repeated‐measures design.

Methods

On consecutive days, 10 individuals (6 males, 4 females) with scores indicating vocal fatigue on the Vocal Fatigue Index completed two 10‐minute vocal exertion tasks. Vocal rest or SOVTEs were interspersed in counterbalanced order between exertion tasks. Respiratory kinematic, acoustic, aerodynamic, and self‐perceptual measures were collected at baseline, following vocal exertion, following SOVTE/vocal rest, and following the second exertion task.

Results

Acute vocal exertion worsened phonation threshold pressure (P < .001) and vocal effort (P < .001) and reduced maximum fundamental frequency (P < .001). Speech was terminated at lower lung volumes following vocal exertion (decreased lung volume termination [LVT], P < .001). Exertion‐induced changes in vocal effort and LVT were significantly reversed by both vocal rest and SOVTE. Detrimental changes in voice measures reoccurred following the second vocal exertion task. SOVTE and vocal rest protected against changes in respiratory kinematics when vocal exertion was resumed.

Conclusions

Vocal exertion impacted laryngeal, respiratory, and self‐perceptual measures in individuals with vocal fatigue. Both SOVTE and vocal rest partially mitigated changes in voice measures and prompted more efficient respiratory strategies that were maintained when vocal exertion resumed. These data increase our understanding of how individuals with vocal fatigue respond to vocal exertion tasks and offer preliminary guidance for optimal clinical recommendations.

Level of Evidence

3 Laryngoscope, 131:2732–2739, 2021
Root, not aboveground litter, controls soil carbon storage under grazing exclusion across grasslands worldwide
Authors: Su Jishuai , Xu Fengwei
Published: May 2021

Grazing exclusion is a common management strategy for improving grasslands degraded due to overgrazing. Although previous meta‐analyses proved that grazing exclusion improved soil carbon (C) storage of grasslands in China, we know little about its effect on grassland ecosystems elsewhere and whether litter accumulation induced by grazing exclusion regulates soil C storage. Using meta‐analysis, we integrated 91 publications to examine the effects of grazing exclusion on community litter and soil C storage, accompanied by analysis of the regulating roles of body size of herbivore, climatic conditions, and grazing exclusion duration. We found that grazing exclusion enhanced litter biomass and decomposition rate but did not change litter chemical quality. Generally, grazing exclusion enhanced plant production and soil C storage across grassland worldwide. Exclusion of medium and small herbivores had stronger effects on aboveground litter production and soil C storage than exclusion of large herbivores, and grazing exclusion's enhancement on litter production and soil C storage tended to increase as grazing exclusion proceeded. Notably, grazing exclusion‐induced increase in aboveground litter biomass was attributed to the increase in biomass of graminoids, while root biomass, not aboveground litter biomass, primarily regulated the increase in soil C storage. The stimulating effect of grazing exclusion on soil C storage was enhanced possibly due to enhanced root biomass response along a precipitation gradient. Generally, our study provided new insights that management practice under grazing exclusion should take plant community dynamics, grazing exclusion duration, preceding grazer type, and climate conditions into account simultaneously.
Factors modulating herbivory patterns in Cymodocea nodosa meadows
Authors: Jiménez‐Ramos Rocío , Egea Luis G. , Vergara Juan J. , Brun Fernando G.
Published: May 2021

In coastal marine food webs, seagrass‐grazer interactions play a fundamental role in ecological processes by regulating the structure and functioning of plant communities. Therefore, assessing the strength of these seagrass‐grazer links and identifying the mechanisms that regulate these relationships are crucial to increasing our understanding of community and ecosystem structure and dynamics. Herbivory on the temperate seagrass Cymodocea nodosa was evaluated in four locations with contrasting abiotic and biotic factors (i.e., depth; meadow size; seagrass shoot density, productivity, and leaf traits; and herbivore presence) using cross‐transplantation experiments carried out once per season to account for seasonal variation. Patterns of feeding rates on C. nodosa meadows showed high temporal variability, with peaks occurring in spring and summer. Results indicate that between 46.59% and 74.08% of the annual leaf production is lost to herbivory at the locations sampled in this study. Herbivory rates increased with higher nitrogen content and shoot density for all types of consumers (mesograzers, fishes, and sea urchins). This work highlights the need to integrate the abiotic and biotic factors modulating herbivory patterns, particularly in a foundation species like C. nodosa, for which changes in plant traits and grazer abundance may trigger trophic cascades with far‐reaching consequences for associated species.
Ion spectroscopy in methane activation
Authors: Roithová Jana , Bakker Joost M.
Published: May 2021

This review is devoted to ion spectroscopy studies of complexes relevant for the understanding of methane activation with metal ions and clusters. Methane activation starts with the formation of a complex with a metal ion. The degree of the interaction between an intact methane molecule and the ion can be monitored by the perturbations of C–H stretch vibrations in the methane molecule. Binding mediated by the electrostatic interaction results in a η3 type coordination of methane. In contrast, binding governed by orbital interactions results in a η2 type coordination of methane. We further review the spectroscopic characterization of activation products of metal–methane reactions, such as the metal–carbene and carbyne products resulting from the interaction of selected 5d metals with methane. The focus of recent research in the field has shifted towards the investigation of interactions between methane and metal clusters. We show examples highlighting that metal clusters can be more reactive in methane activation reactions.
Impact mechanism of supervisor developmental feedback on employee workplace learning
Authors: Wang Shunlin , Zhang Xiangqian
Published: May 2021

Based on the mental simulation duality, this paper adopts the expected successful performance and self‐goal setting as mediating variables and takes the dual system theory. This paper constructs a chain mediating model in which supervisor developmental feedback affects employee workplace learning. A study of 449 samples proves that supervisor developmental feedback can significantly improve employee workplace learning; expected successful performance and self‐goal setting are significant independent mediating variables in the positive impact of supervisor developmental feedback on employee workplace learning; the supervisor developmental feedback promotes self‐goal setting through expected successful performance and then positively affects employee workplace learning.
Efficacy of sliced nerves of different thickness in a biodegradable nerve conduit to promote Schwann cell migration and axonal growth: An experimental study in the rat model
Authors: Sueyoshi Yu , Isogai Noritaka , Nagumo Yoshiaki , Onodera Yuta , Teramura Takeshi , Asamura Shinichi , Kusuhara Hirohisa
Published: May 2021

Background

Using the rat sciatic nerve model, sliced nerves of different thickness was combined to a biodegradable nerve conduit and the amount of nerve fragment necessary to promote nerve regeneration was investigated.

Materials and Methods

Harvested sciatic nerve (n = 6) was processed in sliced nerve of the different width; 2, 1, 0.5 mm, respectively. Western blot analysis was carried out to determine protein expression of Erk1/2. Subsequently, a total of 246 rats were used to create a 10 mm gap in the sciatic nerve. A polyglycolic acid‐based nerve conduit was used to bridge the gap, with one sliced (width; 2, 1, 0.5 mm) or two (width; 1 mm × 2) incorporated within the conduit (n = 6 at each point in each group). At 2, 4, 8, and 20 weeks after surgery, samples were resected and subjected to immune‐histological, transmission electron microscopic, and motor functional evaluation for nerve regeneration.

Results

Western blot analysis demonstrated Erk1/2 expressions were significantly increased in the groups of 2‐mm and 1‐mm width and attenuated in the 0.5‐mm width group (p < .05). The immune‐histological study showed the migration of Schwann cells and axon elongation were significantly extended in the groups of 2‐mm, 1‐mm, and 1 mm × 2 width at 4 weeks (p < .01), in which nerve conduction velocity was marked at 20 weeks (p < .01) after implantation.

Conclusion

When nerve tissue was inserted in the biodegradable nerve conduit as a sliced nerve, the method of inserting two sheets with a slice width of 1 mm most strongly accelerated motor function.
Electromagnetic field and three‐phase lag in a compressed rotating isotropic homogeneous micropolar thermo‐viscoelastic half‐space
Authors: Bayones Fatimah S. , Abo‐Dahab Sayed M. , Abd‐Alla Abdelmooty M. , Kilany Araby A.
Published: May 2021

Using a thermal shock of the ramp type, the authors constructed a unique mathematical three‐phase‐lag scheme in a compressed rotating isotropic homogeneous micropolar thermo‐viscoelastic medium. The model is applied to solve an issue of an exactly performing half‐space exposed to defined boundary circumstances with an electromagnetic field. Normal mode analysis and Lame's potentials methods were used to obtain the analytical answers. The authors were interested in studying the effect of the initial stress, ramp time, magnetic field, and rotation on distributing, displacement, temperature, and stress, as well as induced electric and magnetic distribution. The findings showed that the impact of the viscous, ramp parameter, rotation, phase lag, magnetic field, and initial stress on the micropolar thermo‐viscoelastic medium is distinct.
Research on high luminous efficiency, high color rendering index chips on board light emitting diode and excitation and excitation saturation effect of phosphor
Authors: Wen Zuojie , Zhang Rongrong , Li Bingqian , Liang Shenghua , Yang Mingde , Xia Zhenghao
Published: May 2021

A kind of chips on board (COB) package of light emitting diode (LED) light source is designed and produced. By reducing the current density and using the mirror aluminum substrate with high reflectivity to improve the luminous efficiency. Meanwhile, three kinds of red phosphors with peak wavelength of 630 nm, 631 nm and 639 nm are added on the basis of yellow‐green phosphors, which increase within the range of red light LED spectrum composition, improve the LED color rendering index. The measurement results show that under 500 mA forward current, the luminous flux density of LED on the luminous surface with an area of 227 mm2 reaches 14.4 lm/mm2, the luminous efficiency reaches 175.5 lm/W, and the color rendering index reaches 89.3. It is found in the process of measuring the LED color temperature changes slightly with the current change, and by calculating that the proportion of blue photons in the LED spectrum is increasing gradually, the cause of this phenomenon is the phosphor excitation efficiency is saturation when the optical power density is high, which is influenced in two aspects: the proportion of photons absorbed by phosphor or the phosphor excitation efficiency decreases, the two factors together or separately cause the phosphor excitation saturation effect.
The use of eculizumab in ventilator‐dependent myasthenia gravis patients
Authors: Usman Uzma , Chrisman Christina , Houston Drew , Haws Clara Chow , Wang Alan , Muley Suraj
Published: May 2021

Introduction/Aims

Eculizumab has been shown to be efficacious in acetylcholine receptor antibody–positive (AChR+) Myasthenia Gravis Foundation of America (MGFA) class II, III, and IV generalized myasthenia gravis (gMG) patients. However, it has not been studied in MGFA class V gMG patients.

Methods

We report three AChR+, refractory, MGFA class V gMG patients treated with eculizumab. MGFA class, MG‐Composite (MGC) score and MG Activities of Daily Living (MG‐ADL) score were assessed before and after eculizumab.

Results

Two of three gMG patients, refractory to intravenous immunoglobulin, plasmapheresis, prednisone, and (in one case) rituximab, showed a robust response to eculizumab with marked improvement in MGFA, MG‐ADL, and MGC measures. The third patient showed a partial response to eculizumab but remained on noninvasive ventilation and gastrostomy intubation. Patients 1 and 2 achieved minimal manifestation status at week 4 and week 6, respectively, and showed continued improvement on MG‐ADL and MGC scores through weeks 55 and 43, respectively, with eculizumab. The third patient showed a partial response at week 10, followed by a slight decline in his MG‐ADL score, but noted a slow but an incomplete improvement afterward on MG‐ADL and MGC scores, possibly due to delayed eculizumab infusion.

Discussion

Eculizumab may play a role in the treatment of patients with MGFA class V, refractory gMG. Larger studies are required to provide further evidence.
Two‐dimensional photonic metasurfaces for slow light‐controlled photocatalysis
Authors: Capitolis Jérôme , Hamandi Marwa , Hochedel Marion , El‐Jallal Said , Drouard Emmanuel , Chevalier Céline , Leclercq Jean‐Louis , Penuelas José , Dursap Thomas , Brottet Solène , Devif Brice , Nguyen Hai Son , Berhault Gilles , Chovelon Jean‐Marc , Ferronato Corinne , Guillard Chantal , Puzenat Eric , Crespo‐Monteiro Nicolas , Reynaud Stephanie , Jourlin Yves , Bugnet Matthieu , Seassal Christian
Published: May 2021

Photocatalysis using semiconductor materials like titania (TiO2) is a key method for environmental purification or solar fuel generation. Nanostructures that maximize incident light absorption are highly desired to enhance depollution rate or solar‐to‐fuel conversion efficiency in limited volumes of catalysts. Here, we report on structural and optical properties of metasurfaces based on a 20 nm thick anatase layer conformally deposited onto a wavelength‐scale two‐dimensional periodic photonic lattice. We investigate the NO degradation using such metasurfaces, and evaluate the impact of the patterning on photocatalytic activities between 340 and 400 nm. In the 380–385 nm range, the mean photochemical efficiency is increased by a factor up to 5.7 compared to flat references, with an overall three‐fold enhancement within the whole spectral range of interest. This approach can be applied to numerous types of systems by varying active materials, leading to substantial improvements in air/water depollution, water splitting or artificial photosynthesis processes.
Investigation on microcapsule self‐healing mechanism of polymer matrix composites based on numerical simulation
Authors: Gao Chongyang , Ruan Huanren , Yang Chenlong , Wang Fang
Published: May 2021

Since delamination always occurs in the laminate structures of fiber reinforced polymer composites in engineering applications, developing self‐healing composites has become more and more important nowadays, especially for large‐scale composite equipment, which is difficult to maintain when in service. In this paper, the micromechanical finite element (FE) models are developed for the polymer matrix composites containing self‐healing microcapsules. Based on mesoscale FE simulation and cross reference to related experimental results, we firstly reveal the rupture mechanism of microcapsules, in which the interaction between the microcapsules and microcracks propagated in the resin matrix is investigated by using the extended finite element method in ABAQUS. The mesoscale characteristics of the self‐healing agent, dicyclopentadiene, during the healing process, are revealed with the help of the fluid–solid coupling FE module. Especially, the dynamic filling mechanism of the self‐healing agent within the microcrack planes is physically interpreted by the use of the capillary effect and contact angle principle. Finally, the healing efficiencies of self‐healing composites with different microcapsule sizes and volume fractions are quantitatively evaluated via the virtual mechanical tests of fracture toughness. To be emphasized is that most of the simulation results obtained in this work have exhibited good agreements with the corresponding experimental data, showing a robust reliability of our FE models.
Using digital image correlation for in situ strain and damage monitoring in hybrid fiber laminates under in‐plane shear loading
Authors: Emami Tabrizi Isa , Alkhateab Baidaa , Seyyed Monfared Zanjani Jamal , Yildiz Mehmet
Published: May 2021

Utilizing resistive strain gauges for V‐notch shear tests in fiber reinforced laminates is usually limited to low strain values due to technical uncertainties imposed by the measurement technique and also the progressive damage development in the notched region of the composite. Therefore, this study investigates an alternative approach by using digital image correlation system and further comparison with resistive strain gauge to identify the effect of heterogenous nature of damage development on measurement results. Moreover, glass/carbon fiber hybrid and non‐hybrid laminates are tested in two major directions through the same approach to determine the effect of stacking sequence in spatial microdamage accumulation. It is shown that tailoring appropriate region of interest for full field strain measurement at various stages of loading enables proper monitoring of microdamage accumulation and thereby delivers a precise stress–strain behavior for hybrid and non‐hybrid laminates. Comparison of the strain maps for hybrid laminates tested in 0° direction, shows that the presence of carbon plies at the surface results in uniform strain distribution between the notches of the test sample. In contrast, a non‐homogeneous strain map with separate regions of high strain gradient are observed for hybrid specimens with glass plies at surface, which can cause underestimation of average shear strain by resistive strain gauges. On the other hand, it is shown that strain maps for hybrid samples tested at 90° configuration is analogous regardless of the stacking sequence, and damage accumulation in these samples is most likely related to relative volume fraction of various fibers in hybrid laminate.
Selective contacts and fill factor limitations in heterojunction solar cells
Authors: Serenelli Luca , Martini Luca , Menchini Francesca , Izzi Massimo , de Cesare Giampiero , Condorelli Giuseppe , Gerardi Cosimo , Muñoz Delfina , Tucci Mario
Published: May 2021

Crystalline silicon‐based heterojunction (HJ) solar cells are becoming the best choice for manufacturing companies, because of the low temperature processes useful for very thin silicon wafers and the possibility to easily achieve cells efficiencies higher than 22% on n‐type silicon wafers. However, the maximum cell efficiency is still limited by the typical Fill Factor (FF) value of 82%. This issue is due to several factors, some of which are sometimes underestimated, like the base contact. Indeed, a potential mismatch between the work functions of the transparent conductive oxide and the base doped layer can give rise to a small barrier against electrons collection, which is not easy to recognize when the cell FF overcomes 80%. Also a low doping efficiency of the p‐type amorphous layer at the emitter side can negatively affect the FF. In this case, even if high efficiency cells are produced, their full potential is still unexploited. Thus, both selective contacts of the cell, even if apparently optimized to achieve very good results, can hide problems that limit the final cell FF and efficiency. In a previous work, an experimental method and a model to individuate hidden barriers at the base contact on n‐type crystalline silicon‐based HJs have been provided. In this paper, that model is applied to experimental data obtained from the characterization of both commercial and laboratory level HJ solar cells. Moreover, an easy method to recognize the presence of a barrier to the charge transport at the emitter side of the cell is illustrated.
Drivers of Hsp104 potentiation revealed by scanning mutagenesis of the middle domain
Authors: Ryan Jeremy J. , Bao Aaron , Bell Braxton , Ling Cendi , Jackrel Meredith E.
Published: May 2021

Hsp104, a yeast protein disaggregase, can be potentiated via numerous missense mutations at disparate locations throughout the coiled‐coil middle domain (MD). Potentiated Hsp104 variants can counter the toxicity and misfolding of TDP‐43, FUS, and α‐synuclein, proteins which are implicated in neurodegenerative disorders. However, potentiated MD variants typically exhibit off‐target toxicity. Further, it has remained confounding how numerous degenerate mutations confer potentiation, hampering engineering of therapeutic Hsp104 variants. Here, we sought to comprehensively define the key drivers of Hsp104 potentiation. Using scanning mutagenesis, we iteratively studied the effects of modulation at each position in the Hsp104 MD. Screening this library to identify enhanced variants reveals that missense mutations at 26% of positions in the MD yield variants that counter FUS toxicity. Modulation of the helix 2–helix 3/4 MD interface potentiates Hsp104, whereas mutations in the analogous helix 1–2 interface do not. Surprisingly, we find that there is a higher likelihood of enhancing Hsp104 activity against human disease substrates than impairing Hsp104 native function. We find that single mutations can broadly destabilize the MD structure and lead to functional potentiation, suggesting this may be a common mechanism conferring Hsp104 potentiation. Using this approach, we have demonstrated that modulation of the MD can yield engineered variants with decreased off‐target effects.
Activator protein‐1 mediated CYP6ER1 overexpression in the clothianidin resistance of Nilaparvata lugens (Stål)
Authors: Jin Ruoheng , Wang Yue , He Biyan , Zhang Yunhua , Cai Tingwei , Wan Hu , Jin Byung Rae , Li Jianhong
Published: May 2021

BACKGROUND

Nilaparvata lugens, a destructive rice pest in Asia, has developed resistance to many insecticides, including the neonicotinoid clothianidin. CYP6ER1 plays an important role in N. lugens resistant to clothianidin, but only limited information on the transcriptional regulation of CYP6ER1 overexpression in clothianidin resistance is available.

RESULTS

In this study, the transcription factor activator protein 1 (AP‐1) was found to be overexpressed in a clothianidin‐resistant strain of N. lugens and several field resistant populations. RNA interference‐mediated silencing of NlAP‐1 significantly decreased CYP6ER1 expression and increased the susceptibility of N. lugens to clothianidin. Additionally, NlAP‐1 was highly expressed in egg and adult stages, and in midguts, and NlAP‐1 was upregulated and induced to a greater extent in the clothianidin‐resistant strain after exposure to clothianidin. Finally, dual‐luciferase reporter assays confirmed the interaction between NlAP‐1 and the two predicted binding sites in the CYP6ER1 promoter.

CONCLUSION

NlAP‐1 bound the −1388 to −1208‐bp region of the CYP6ER1 promoter, enhancing its activity and then regulate the expression of CYP6ER1. These findings enhance our knowledge of the transcriptional regulation of the P450 genes that mediate insecticide resistance in insect pests. © 2021 Society of Chemical Industry.
Ergothioneine in a peptide: Substitution of histidine with 2‐thiohistidine in bioactive peptides
Authors: Jenny Kaelyn A. , Ruggles Erik L. , Liptak Matthew D. , Masterson Douglas S. , Hondal Robert J.
Published: May 2021

Ergothioneine (EGT) is the betaine of 2‐thiohistidine (2‐thioHis) and may be the last undiscovered vitamin. EGT cannot be incorporated into a peptide because the α‐nitrogen is trimethylated, although this would be advantageous as an EGT‐like moiety in a peptide would impart unique antioxidant and metal chelation properties. The amino acid 2‐thioHis is an analogue of EGT and can be incorporated into a peptide, although there is only one reported occurrence of this in the literature. A likely reason is the harsh conditions reported for protection of the thione, with similarly harsh conditions used in order to achieve deprotection after synthesis. Here, we report a novel strategy for the incorporation of 2‐thioHis into peptides in which we decided to leave the thione unprotected. This decision was based upon the reported low reactivity of EGT with 5,5′‐dithiobis(2‐nitrobenzoic acid) (DTNB), a very electrophilic disulfide. This strategy was successful, and we report here the synthesis of 2‐thioHis analogues of carnosine (βAH), GHK‐tripeptide, and HGPLGPL. Each of these peptides contain a histidine (His) residue and possesses biological activity. Our results show that substitution of His with 2‐thioHis imparts strong antioxidant, radical scavenging, and copper binding properties to the peptide. Notably, we found that the 2‐thioHis analogue of GHK‐tripeptide was able to completely quench the hydroxyl and ABTS radicals in our assays, and its antioxidant capacity was significantly greater than would be expected based on the antioxidant capacity of free 2‐thioHis. Our work makes possible greater future use of 2‐thioHis in peptides.
The use of local and nonlocal priors in Bayesian test‐based monitoring for single‐arm phase II clinical trials
Authors: Zhou Yanhong , Lin Ruitao , Lee J. Jack
Published: May 2021

Bayesian sequential monitoring is widely used in adaptive phase II studies where the objective is to examine whether an experimental drug is efficacious. Common approaches for Bayesian sequential monitoring are based on posterior or predictive probabilities and Bayesian hypothesis testing procedures using Bayes factors. In the first part of the paper, we briefly show the connections between test‐based (TB) and posterior probability‐based (PB) sequential monitoring approaches. Next, we extensively investigate the choice of local and nonlocal priors for the TB monitoring procedure. We describe the pros and cons of different priors in terms of operating characteristics. We also develop a user‐friendly Shiny application to implement the TB design.
Rosmarinic acid protects mice from imiquimod induced psoriasis‐like skin lesions by inhibiting the IL‐23/Th17 axis via regulating Jak2/Stat3 signaling pathway
Authors: Zhang Miaomiao , Li Ning , Cai Ruhang , Gu Jiangyong , Xie Fuda , Wei Hong , Lu Chuanjian , Wu Dinghong
Published: May 2021

IL‐23/Th17 (IL‐17) axis plays a critical role in psoriasis. Rosmarinic acid (RA) was proved the inhibitory effect of T cell infiltration in the skin. However, whether and how RA has beneficial effects on psoriasis did not really know yet. So lipopolysaccharide (LPS)‐induced abnormal proliferation Hacat cell line and Imiquimod (IMQ)‐induced psoriasis‐like mouse dermatitis were used to assess the pharmacological effects and mechanisms of RA by Psoriasis Area Severity Index (PASI) score, histopathology, flow cytometry, reverse transcription‐polymerase chain reaction (RT‐PCR) and western blotting. The results showed that RA inhibited LPS‐induced aberrant expression of Hacat cell line, and significantly alleviated IMQ‐induced skin inflammation. Although RA had no obviously effect on the ratio of epidermal Langerhans cell (LC) and LC migration from the skin to the skin draining lymph nodes, RA inhibited the expression of IL‐23 in skin lesions, as well as reduced the differentiation of Th17 cells and producing of IL‐17A by down regulating the transcriptor factor RORγt and JAK2/Stat3 signal pathway, comparing to IMQ treated group. The findings suggest that RA inhibits psoriasis‐like skin inflammation in vivo and in vitro by reducing the expression of IL‐23, inhibiting Th17 dominated inflammation and down regulating the Jak2/Stat3 signal pathway.
Simulating the dynamics of atherosclerosis to the incidence of myocardial infarction, applied to the KORA population
Authors: Simonetto Cristoforo , Rospleszcz Susanne , Heier Margit , Meisinger Christa , Peters Annette , Kaiser Jan Christian
Published: May 2021

Analyzing epidemiological data with simplified mathematical models of disease development provides a link between the time‐course of incidence and the underlying biological processes. Here we point out that considerable modeling flexibility is gained if the model is solved by simulation only. To this aim, a model of atherosclerosis is proposed: a Markov Chain with continuous state space which represents the coronary artery intimal surface area involved with atherosclerotic lesions of increasing severity. Myocardial infarction rates are assumed to be proportional to the area of most severe lesions. The model can be fitted simultaneously to infarction incidence rates observed in the KORA registry, and to the age‐dependent prevalence and extent of atherosclerotic lesions in the PDAY study. Moreover, the simulation approach allows for non‐linear transition rates, and to consider at the same time randomness and inter‐individual heterogeneity. Interestingly, the fit revealed significant age dependence of parameters in females around the age of menopause, qualitatively reproducing the known vascular effects of female sex hormones. For males, the incidence curve flattens for higher ages. According to the model, frailty explains this flattening only partially, and saturation of the disease process plays also an important role. This study shows the feasibility of simulating subclinical and epidemiological data with the same mathematical model. The approach is very general and may be extended to investigate the effects of risk factors or interventions. Moreover, it offers an interface to integrate quantitative individual health data as assessed, for example, by imaging.
Do Patient Characteristics Matter When Calculating Sample Size for Eczema Clinical Trials?
Authors: Howells L. , Gran S. , Chalmers J. R. , Stuart B. , Santer M. , Bradshaw L. , Gaunt D. M. , Ridd M. J. , Gerbens L. A. A. , Spuls P. I. , Huang C. , Francis N. A. , Thomas K. S.
Published: May 2021

Background

The Patient-Oriented Eczema Measure (POEM) is the core outcome instrument recommended for measuring patient-reported atopic eczema symptoms in clinical trials. To ensure that the statistical significance of clinical trial results is meaningful, trials are often designed by specifying the target difference in the primary outcome as part of the sample size calculation. One method used to specify the target difference is a score that corresponds to a standardized effect size.

Objectives

to assess how the standardized effect size of POEM scores vary across age, gender, ethnicity and disease severity.

Methods

This study combined data from five UK-based randomized clinical trials of eczema treatments in order to assess differences in self-reported eczema symptoms (POEM) corresponding to a standardized effect size (0.5 SD of baseline POEM scores) across age, gender, ethnicity and disease severity.

Results

POEM scores corresponding to 0.5 SD(baseline) were remarkably consistent across participants of varying ages, gender, ethnicity and disease severity from datasets of five UK trials in children (range 2.99–3.45).

Conclusions

This study provides information that can support those designing clinical trials to determine their sample size and can aid individuals interpreting trial results. Further exploration of differences in populations beyond the United Kingdom is needed.
Noncontact Multiphysics Probe for Spatiotemporal Resolved Single‐Cell Manipulation and Analyses
Authors: Brimmo Ayoola T. , Menachery Anoop , Sukumar Pavithra , Qasaimeh Mohammad A.
Published: May 2021

Heterogeneity and spatial arrangement of individual cells within tissues are critical to the identity of the host multicellular organism. While current single‐cell techniques are capable of resolving heterogeneity, they mostly rely on extracting target cells from their physiological environment and hence lose the spatiotemporal resolution required for understanding cellular networks. Here, a multifunctional noncontact scanning probe that can precisely perform multiple manipulation procedures on living single‐cells, while within their physiological tissue environment, is demonstrated. The noncontact multiphysics probe (NMP) consists of fluidic apertures and “hump” shaped electrodes that simultaneously confine reagents and electric signals with a single‐cell resolution. The NMP's unique electropermealization‐based approach in transferring macromolecules through the cell membrane is presented. The technology's adjustable spatial ability is demonstrated by transfecting adjacent single‐cells with different DNA plasmid vectors. The NMP technology also opens the door for controllable cytoplasm extraction from living single‐cells. This powerful application is demonstrated by executing multiple time point biopsies on adherent cells without affecting the integrity of the extracted macromolecules or the viability of cells. Furthermore, the NMP's function as an electro‐thermal based microfluidic whole‐cell tweezer is reported. This work offers a multifunctional tool with unprecedented probing features for spatiotemporal single‐cell analysis within tissue samples.