bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid assessment of heavy metal pollution using ion-exchange resin sachets and micro-XRF core-scanning
Authors: Huang Jyh-Jaan Steven , Lin Sheng-Chi , Löwemark Ludvig , Liou Sofia Ya Hsuan , Chang Queenie , Chang Tsun-Kuo , Wei Kuo-Yen , Croudace Ian W.
Published: April 2019

Conventional pollution monitoring strategies for heavy metals are often costly and unpractical. Innovative sampling and analytical approaches are therefore needed to efficiently monitor large areas. This study presents a novel, simple, fast, and inexpensive method to monitor heavy metal pollution that uses cation-exchange resin sachets and the micro-XRF core-scanning technique (XRF-CS). The resin passive samplers act as concentrators of cationic species and can be readily deployed spatially and temporally to record pollution signals. The large number of analytical tasks are then overcome by the fast and non-destructive XRF-CS to precisely assess elemental concentrations. Quantifying element loading involves direct comparison with a set of identically prepared and scanned resin reference standards containing Ca, Ti, Cr, Mn, Ni, Cu, Zn, Pb. The results show that within the test range (from 0–1000 s mg kg−1), the calibration lines have excellent regressions (R2 ≥ 0.97), even at the shortest exposure time (1 s). A pilot field survey of a suspected polluted area in central Taiwan, where 30 resin sachets had been deployed, identified a pollution hot spot in a rapid and economical manner. Therefore, this approach has the potential to become a valuable tool in environmental monitoring and forensics.
Transition metal trifluoroacetates (M = Fe, Co, Mn) as precursors for uniform colloidal metal difluoride and phosphide nanoparticles
Authors: Guntlin Christoph P. , Kravchyk Kostiantyn V. , Erni Rolf , Kovalenko Maksym V.
Published: April 2019

We report a simple one-pot synthesis of uniform transition metal difluoride MF2 (M = Fe, Mn, Co) nanorods based on transition metal trifluoroacetates (TMTFAs) as single-source precursors. The synthesis of metal fluorides is based on the thermolysis of TMTFAs at 250–320 °C in trioctylphosphine/trioctylphosphine oxide solvent mixtures. The FeF2 nanorods were converted into FeF3 nanorods by reaction with gaseous fluorine. The TMTFA precursors are also found to be suitable for the synthesis of colloidal transition metal phosphides. Specifically, we report that the thermolysis of a cobalt trifluoroacetate complex in trioctylphosphine as both the solvent and the phosphorus source can yield 20 nm long cobalt phosphide nanorods or, 3 nm large cobalt phosphide nanoparticles. We also assess electrochemical lithiation/de-lithiation of the obtained FeF2 and FeF3 nanomaterials.
Local stress and pressure in an inhomogeneous system of spherical active Brownian particles
Authors: Das Shibananda , Gompper Gerhard , Winkler Roland G.
Published: April 2019

The stress of a fluid on a confining wall is given by the mechanical wall forces, independent of the nature of the fluid being passive or active. At thermal equilibrium, an equation of state exists and stress is likewise obtained from intrinsic bulk properties; even more, stress can be calculated locally. Comparable local descriptions for active systems require a particular consideration of active forces. Here, we derive expressions for the stress exerted on a local volume of a systems of spherical active Brownian particles (ABPs). Using the virial theorem, we obtain two identical stress expressions, a stress due to momentum flux across a hypothetical plane, and a bulk stress inside of the local volume. In the first case, we obtain an active contribution to momentum transport in analogy to momentum transport in an underdamped passive system, and we introduce an active momentum. In the second case, a generally valid expression for the swim stress is derived. By simulations, we demonstrate that the local bulk stress is identical to the wall stress of a confined system for both, non-interacting ABPs as well as ABPs with excluded-volume interactions. This underlines the existence of an equation of state for a system of spherical ABPs. Most importantly, our calculations demonstrated that active stress is not a wall (boundary) effect, but is caused by momentum transport. We demonstrate that the derived stress expression permits the calculation of the local stress in inhomogeneous systems of ABPs.
A combined FSTRA-shotgun proteomics approach to identify molecular changes in zebrafish upon chemical exposure
Authors: Ayobahan Steve U. , Eilebrecht Elke , Kotthoff Matthias , Baumann Lisa , Eilebrecht Sebastian , Teigeler Matthias , Hollert Henner , Kalkhof Stefan , Schäfers Christoph
Published: April 2019

The fish short-term reproduction assay (FSTRA) is a common in vivo screening assay for assessing endocrine effects of chemicals on reproduction in fish. However, the current reliance on measures such as egg number, plasma vitellogenin concentration and morphological changes to determine endocrine effects can lead to false labelling of chemicals with non-endocrine modes- of-action. Here, we integrated quantitative liver and gonad shotgun proteomics into the FSTRA in order to investigate the causal link between an endocrine mode-of-action and adverse effects assigned to the endocrine axis. Therefore, we analyzed the molecular effects of fadrozole-induced aromatase inhibition in zebrafish (Danio rerio). We observed a concentration-dependent decrease in fecundity, a reduction in plasma vitellogenin concentrations and a mild oocyte atresia with oocyte membrane folding in females. Consistent with these apical measures, proteomics revealed a significant dysregulation of proteins involved in steroid hormone secretion and estrogen stimulus in the female liver. In the ovary, the deregulation of estrogen synthesis and binding of sperm to zona pellucida were among the most significantly perturbed pathways. A significant deregulation of proteins targeting the transcriptional activity of estrogen receptor (esr1) was observed in male liver and testis. Our results support that organ- and sex-specific quantitative proteomics represent a promising tool for identifying early gene expression changes preceding chemical-induced adverse outcomes. These data can help to establish consistency in chemical classification and labelling.
Enhanced output performance on LbL multilayer PVDF-TrFE piezoelectric films for charging supercapacitor
Authors: Chung Moon Hyun , Yoo Seunghwan , Kim Hyun-Jun , Yoo Jungjoon , Han Seol-Yee , Yoo Kyung-Hwa , Jeong Hakgeun
Published: April 2019

The piezoelectric nanogenerator (PENG) has the potential to become a promising power supply for monitoring and sensors in Internet of Things (IoT) systems through wireless networks. In order to further increase the utilization of energy harvesters in an IoT system, we introduce a novel approach that greatly enhances the piezoelectric output performances by employing the layer-by-layer (LbL) method. Poly(vinylidenefluoride-co-trifluoroethylene) (PVDF-TrFE) polymer film, which has piezoelectric properties and mechanical flexibility, was used for the active layer in PENG. The maximum open-circuit voltage and closed-circuit current of the LbL multilayer PENG reached 34 V and 100 nA, respectively. In particular, the closed-circuit current of the LbL multilayer PENG was dramatically improved to be five times higher than that of the single-layer PENG. Furthermore, a supercapacitor was employed to investigate the energy storage capability of PENGs using different methods. The proposed LbL multilayer PENG is expected to be a candidate for a promising power supply for self-powered systems in the IoT system.
Long-term variations in PM2.5 concentrations under changing meteorological conditions in Taiwan
Authors: Cheng Fang-Yi , Hsu Chia-Hua
Published: April 2019

With emission control efforts, the PM2.5 concentrations and PM2.5 exceedance days (daily mean PM2.5 concentrations >35 µg m−3) show an apparent declining trend from 2006–2017. The PM2.5 concentrations increase from the northern to southern part of western Taiwan, and reductions in the PM2.5 concentration generally decrease from northern to southern part of western Taiwan. Thus, mitigation of the PM2.5 problem is less effective in southwestern Taiwan than in other regions in Taiwan. Analysis of a 39-year ERA-interim reanalysis dataset (1979–2017) reveals a weakening of the East Asian winter monsoon, a reduction in northeasterly (NE) monsoonal flow, and a tendency of enhanced stably stratified atmospheric structures in Taiwan and the surrounding area. The observed surface wind speed also presents a long-term decline. We can conclude that the long-term PM2.5 variations in Taiwan are mainly associated with changes in local anthropogenic emissions and modulated by short-term yearly variations due to strong haze events in China. In southwestern Taiwan, the long-term trend of PM2.5 reductions is possibly offset by worsening weather conditions, as this region is situated on the leeside of the mountains and often subject to stagnant wind when under the influence of NE monsoonal flow.
Ancient Mammalian and Plant DNA from Late Quaternary Stalagmite Layers at Solkota Cave, Georgia
Authors: Stahlschmidt M. C. , Collin T. C. , Fernandes D. M. , Bar-Oz G. , Belfer-Cohen A. , Gao Z. , Jakeli N. , Matskevich Z. , Meshveliani T. , Pritchard J. K. , McDermott F. , Pinhasi R.
Published: April 2019

Metagenomic analysis is a highly promising technique in paleogenetic research that allows analysis of the complete genomic make-up of a sample. This technique has successfully been employed to archaeological sediments, but possible leaching of DNA through the sequence limits interpretation. We applied this technique to the analysis of ancient DNA (aDNA) from Late Quaternary stalagmites from two caves in Western Georgia, Melouri Cave and Solkota. Stalagmites form closed systems, limiting the effect of leaching, and can be securely dated with U-series. The analyses of the sequence data from the Melouri Cave stalagmite revealed potential contamination and low preservation of DNA. However, the two Solkota stalagmites preserved ancient DNA molecules of mammals (bear, roe deer, bats) and plants (chestnut, hazelnut, flax). The aDNA bearing layers from one of the two Solkota stalagmites were dated to between ~84 ka and ~56 ka BP by U-series. The second Solkota stalagmite contained excessive detrital clay obstructing U-series dating, but it also contained bear bones with a minimum age of ~50 BP uncalibrated years and ancient DNA molecules. The preservation of authentic ancient DNA molecules in Late Quaternary speleothems opens up a new paleogenetic archive for archaeological, paleontological and paleoenvironmental research.
The characterization of Thermotoga maritima Arginine Binding Protein variants demonstrates that minimal local strains have an important impact on protein stability
Authors: Balasco Nicole , Smaldone Giovanni , Vigorita Marilisa , Del Vecchio Pompea , Graziano Giuseppe , Ruggiero Alessia , Vitagliano Luigi
Published: April 2019

The Ramachandran plot is a versatile and valuable tool that provides fundamental information for protein structure determination, prediction, and validation. The structural/thermodynamic effects produced by forcing a residue to adopt a conformation predicted to be forbidden were here explored using Thermotoga maritima Arginine Binding Protein (TmArgBP) as model. Specifically, we mutated TmArgBP Gly52 that assumes a conformation believed to be strictly disallowed for non-Gly residues. Surprisingly, the crystallographic characterization of Gly52Ala TmArgBP indicates that the structural context forces the residue to adopt a non-canonical conformation never observed in any of the high-medium resolution PDB structures. Interestingly, the inspection of this high resolution structure demonstrates that only minor alterations occur. Nevertheless, experiments indicate that Gly52 replacements in TmArgBP produce destabilizations comparable to those observed upon protein truncation or dissection in domains. Notably, we show that force-fields commonly used in computational biology do not reproduce this non-canonical state. Using TmArgBP as model system we here demonstrate that the structural context may force residues to adopt conformations believed to be strictly forbidden and that barely detectable alterations produce major destabilizations. Present findings highlight the role of subtle strains in governing protein stability. A full understanding of these phenomena is essential for an exhaustive comprehension of the factors regulating protein structures.
Zooarchaeology of the social and economic upheavals in the Late Antique-Early Islamic sequence of the Negev Desert
Authors: Marom Nimrod , Meiri Meirav , Tepper Yotam , Erickson-Gini Tali , Reshef Hagar , Weissbrod Lior , Bar-Oz Guy
Published: April 2019

The Byzantine – Islamic transition (7th–8thcenturies CE) in the desert-edge Palaestina Tertia is examined using faunal remains recovered from archaeological sites in the Negev. Archaeozoological analyses suggest sharp differences between Late Byzantine and Early Islamic animal economies, especially in herding patterns and the exploitation of wildlife resources. These differences are suggested to reflect both cultural and land ownership changes following the Arab conquest, against the backdrop of climatic change. The archaeozoological record thereby provides independent evidence to the rise and fall of societal complexity in this marginal region.
Nanoindentation behavior of high entropy alloys with transformation-induced plasticity
Authors: Sinha S. , Mirshams R. A. , Wang T. , Nene S. S. , Frank M. , Liu K. , Mishra R. S.
Published: April 2019

Nanoindentation of three metastable dual-phase high entropy alloys (HEAs) was performed to obtain their inherent elastoplastic deformation responses. Excellent combination of hardness and elastic modulus in as-cast condition confirmed that, their inherently higher strength compared to other HEAs reported in literature, can be attributed to alloy chemistry induced phase stability. Further, hardness of 8.28 GPa combined with modulus of 221.8 GPa was obtained in Fe-Mn-Co-Cr-Si-Cu HEA by annealing the as-cast material, which is the best hardness-modulus combination obtained to date in HEAs from nanoindentation. On the other hand, although Fe-Mn-Co-Cr-Si HEA showed lower hardness and modulus than Fe-Mn-Co-Cr-Si-Al and Fe-Mn-Co-Cr-Si-Cu HEAs, the former alloy exhibited the highest strain rate sensitivity, as determined from tests performed at five different strain rates. The three alloys also had subtle differences in incipient plasticity and elastoplastic behavior, while retaining similar levels of hardness; and nanoindentation response showed microstructural dependence in friction stir processed, annealed and tensile-deformed specimens. Thus, the study highlighted that while higher strength was achieved by designing a class of HEAs with similar composition, any of the individual alloys can be tuned to obtain enhanced properties.
Cryogenian magmatic activity and early life evolution
Authors: Long Jie , Zhang Shixi , Luo Kunli
Published: April 2019

Data from the Qinling Orogenic Belt in China indicate that a strong magmatic-volcanic event on the Snowball Earth during the Cryogenian age (approximately 720–635 million years ago) was followed by a dynamic period of accelerated evolution of early life through the Ediacaran period. The studied volcanics of the Cryogenian Yaolinghe group are mainly represented by andesite, dacite and rhyolite, with minor amounts of basalt, trachy andesite and trachyte towards the top, which formed in the environment of an active island arc related to a continental margin. Compared with average felsic volcanics, the studied Cryogenian marine volcanic strata are enriched (1.5–30.6 times) in Co, Cr, Bi, Ni, Se, Ga, As, Cu, Ba, V, and Zn. Elemental concentrations (P, Cd, Co, Ni, and Se) of the studied volcanics are more than 5–26.4 times those in the contemporaneous Liantuo tillite. We propose that Cryogenian magmatic and volcanic activity increased the flux of some trace nutritional elements into the oceans which possibly provided essential nutrients for the development of early life.
Deep learning predicts hip fracture using confounding patient and healthcare variables
Authors: Badgeley Marcus A. , Zech John R. , Oakden-Rayner Luke , Glicksberg Benjamin S. , Liu Manway , Gale William , McConnell Michael V. , Percha Bethany , Snyder Thomas M. , Dudley Joel T.
Published: April 2019

Hip fractures are a leading cause of death and disability among older adults. Hip fractures are also the most commonly missed diagnosis on pelvic radiographs, and delayed diagnosis leads to higher cost and worse outcomes. Computer-aided diagnosis (CAD) algorithms have shown promise for helping radiologists detect fractures, but the image features underpinning their predictions are notoriously difficult to understand. In this study, we trained deep-learning models on 17,587 radiographs to classify fracture, 5 patient traits, and 14 hospital process variables. All 20 variables could be individually predicted from a radiograph, with the best performances on scanner model (AUC = 1.00), scanner brand (AUC = 0.98), and whether the order was marked “priority” (AUC = 0.79). Fracture was predicted moderately well from the image (AUC = 0.78) and better when combining image features with patient data (AUC = 0.86, DeLong paired AUC comparison, p = 2e-9) or patient data plus hospital process features (AUC = 0.91, p = 1e-21). Fracture prediction on a test set that balanced fracture risk across patient variables was significantly lower than a random test set (AUC = 0.67, DeLong unpaired AUC comparison, p = 0.003); and on a test set with fracture risk balanced across patient and hospital process variables, the model performed randomly (AUC = 0.52, 95% CI 0.46–0.58), indicating that these variables were the main source of the model’s fracture predictions. A single model that directly combines image features, patient, and hospital process data outperforms a Naive Bayes ensemble of an image-only model prediction, patient, and hospital process data. If CAD algorithms are inexplicably leveraging patient and process variables in their predictions, it is unclear how radiologists should interpret their predictions in the context of other known patient data. Further research is needed to illuminate deep-learning decision processes so that computers and clinicians can effectively cooperate.
Flexible-to-rigid transition is central for substrate transport in the ABC transporter BmrA from Bacillus subtilis
Authors: Lacabanne Denis , Orelle Cédric , Lecoq Lauriane , Kunert Britta , Chuilon Claire , Wiegand Thomas , Ravaud Stéphanie , Jault Jean-Michel , Meier Beat H. , Böckmann Anja
Published: April 2019

ATP-binding-cassette (ABC) transporters are molecular pumps that translocate molecules across the cell membrane by switching between inward-facing and outward-facing states. To obtain a detailed understanding of their mechanism remains a challenge to structural biology, as these proteins are notoriously difficult to study at the molecular level in their active, membrane-inserted form. Here we use solid-state NMR to investigate the multidrug ABC transporter BmrA reconstituted in lipids. We identify the chemical-shift differences between the inward-facing, and outward-facing state induced by ATP:Mg2+:Vi addition. Analysis of an X-loop mutant, for which we show that ATPase and transport activities are uncoupled, reveals an incomplete transition to the outward-facing state upon ATP:Mg2+:Vi addition, notably lacking the decrease in dynamics of a defined set of residues observed in wild-type BmrA. This suggests that this stiffening is required for an efficient transmission of the conformational changes to allow proper transport of substrate by the pump.
A c-di-AMP riboswitch controlling kdpFABC operon transcription regulates the potassium transporter system in Bacillus thuringiensis
Authors: Wang Xun , Cai Xia , Ma Hongdan , Yin Wen , Zhu Li , Li Xinfeng , Lim Heon M. , Chou Shan-Ho , He Jin
Published: April 2019

The intracellular K+ level in bacteria is strictly controlled by K+ uptake and efflux systems. Among these, KdpFABC is a high-affinity K+ transporter system that is generally activated by the KdpDE two-component system in response to K+ limitation stress. However, the regulatory mechanism remains obscure in bacteria lacking the kdpDE genes. Here we report that the transcription of a kdpFABC operon is distinctively regulated by a cyclic diadenylate monophosphate (c-di-AMP) riboswitch located at the 5′-untranslated region of kdp transcript, and binding of c-di-AMP to the riboswitch promotes its intrinsic termination that blocks the kdpFABC transcription. Further, the intracellular c-di-AMP concentration was found to decrease under the K+ limitation stress, leading to transcriptional read-through over the terminator to allow kdpFABC expression. This regulatory element is found predominantly in the Bacillus cereus group and correlate well with the K+ and c-di-AMP homeostasis that affects a variety of crucial cellular functions.
Anti-inflammatory effects of paeoniflorin from Paeonia lactiflora Pall. on human corneal epithelial cells and a mouse model of dry eye disease
Authors: Zhao Mincong , Liu Li , Zheng Yating , Liu Guangrong , Che Biao , Li Penghui , Chen Huixiong , Dong Changzhi , Lin Li , Du Zhiyun
Published: April 2019

Dry eye disease (DED) is characterized by increased osmolality of tears due to a lack of production or increased evaporation of tears.
A hybridization chain reaction coupled with gold nanoparticles for allergen gene detection in peanut, soybean and sesame DNAs
Authors: Yuan Dan , Fang Xueen , Liu Yongxin , Kong Jilie , Chen Qin
Published: April 2019

A HCR coupled with gold nanoparticles to detect allergen genes by using ultraviolet absorption spectra or color changes.
Nature-inspired extracellular matrix coating produced by micro-patterned smooth muscle and endothelial cells endows cardiovascular materials with better biocompatibility
Authors: Han Congzhen , Luo Xiao , Zou Dan , Li Jingan , Zhang Kun , Yang Ping , Huang Nan
Published: April 2019

Functionalizing cardiovascular biomaterials with an extracellular matrix (ECM) via in vitro decellularization has been applied as an effective method to improve the biocompatibility of implants.
Cell-penetrating peptide together with PEG-modified mesostructured silica nanoparticles promotes mucous permeation and oral delivery of therapeutic proteins and peptides
Authors: Tan Xinyi , Zhang Yan , Wang Qian , Ren Tianyang , Gou Jingxin , Guo Wei , Yin Tian , He Haibing , Zhang Yu , Tang Xing
Published: April 2019

Electrostatic particle complexes, CPP/TPP/NP, consisting of PEG-modified silica NPs with TPP and CPP, showed satisfactory stability and mucous penetration.
Designing new Togni reagents by computation
Authors: Jiang Heming , Sun Tian-Yu , Chen Ying , Zhang Xinhao , Wu Yun-Dong , Xie Yaoming , Schaefer Henry F.
Published: April 2019

New trifluoromethylating reagents are designed based on trans influence and steric effect.
Facileo-quinodimethane formation from benzocyclobutenes triggered by the Staudinger reaction at ambient temperature
Authors: Kohyama Aki , Koresawa Eri , Tsuge Kiyoshi , Matsuya Yuji
Published: April 2019

4π Ring-opening at ambient temperature triggered by the Staudinger reaction.
Mild pyrolysis of ionic self-assembled cobalt porphyrins on carbon toward efficient electrochemical conversion of CO2 to CO
Authors: Zhang Xue , Liu Huiyuan , Qin Jiaqi , Han Hongsa , Qiu Chenxi , Zhang Siyu , Hao Xinyu , Liu Wei , Song Yujiang
Published: April 2019

Heat-treated self-assembled cobalt porphyrins on carbon electrochemically convert CO2 to CO with a high faradaic efficiency and at a low overpotential.
Rhodium(ii)-catalyzed annulation ofN-sulfonyl-1,2,3-triazoles with 1,3,5-triazinanes to produce octahydro-1H-purine derivatives: a combined experimental and computational study
Authors: Ge Jiemin , Wu Xueli , Bao Xiaoguang
Published: April 2019

The Rh(ii)-catalyzed annulation ofN-sulfonyl-1,2,3-triazoles with 1,3,5-triazinanes leading to the octahydro-1H-purine derivatives with moderate to good yields is described in this communication.
Correlating blocking temperatures with relaxation mechanisms in monometallic single-molecule magnets with high energy barriers (Ueff > 600 K)
Authors: Giansiracusa Marcus J. , Kostopoulos Andreas K. , Collison David , Winpenny Richard E. P. , Chilton Nicholas F.
Published: April 2019

Correlating blocking temperatures with relaxation mechanisms in single-molecule magnets.
Dithiothreitol-assisted polysulfide reduction in the interlayer of lithium–sulfur batteries: a first-principles study
Authors: Liu Jiaqin , Li Mo , Zhang Xiaofei , Zhang Qi , Yan Jian , Wu Yucheng
Published: April 2019

The reaction mechanism of dithiothreitol-assisted polysulfide reduction in lithium–sulfur batteries was clarified based on systematic theoretical study.
Influence of the hydrophobic domain on the self-assembly and hydrogen bonding of hydroxy-amphiphiles
Authors: Andrushchenko Valery , Pohle Walter
Published: April 2019

IR spectroscopy paired with calculations reveals that structurally similar amphiphiles ODA and DOG form very different supramolecular assemblies.
Functional materials: making the world go round
Authors: Wächtler Maria , González Leticia , Dietzek Benjamin , Turchanin Andrey , Roth Christina
Published: April 2019

This themed issue includes a collection of articles on functional materials.
Phthalocyanines and porphyrinoid analogues as hole- and electron-transporting materials for perovskite solar cells
Authors: Urbani Maxence , de la Torre Gema , Nazeeruddin Mohammad Khaja , Torres Tomás
Published: April 2019

Stable macrocyclic compounds based on phthalocyanines and porphyrins as hole- and electron-transporting materials for perovskite solar cells are reviewed.
Modelling consortium for chemistry of indoor environments (MOCCIE): integrating chemical processes from molecular to room scales
Authors: Shiraiwa Manabu , Carslaw Nicola , Tobias Douglas J. , Waring Michael S. , Rim Donghyun , Morrison Glenn , Lakey Pascale S. J. , Kruza Magdalena , von Domaros Michael , Cummings Bryan E. , Won Youngbo
Published: April 2019

We report on the development of a modelling consortium for chemistry in indoor environments that connects models over a range of spatial and temporal scales, from molecular to room scales and from sub-nanosecond to days, respectively.
Influence of nonionic and ionic surfactants on the antifungal and mycotoxin inhibitory efficacy of cinnamon oil nanoemulsions
Authors: Wu Dianhui , Lu Jian , Zhong Shaobin , Schwarz Paul , Chen Bingcan , Rao Jiajia
Published: April 2019

The influence of ionic surfactants (cationic surfactant lauric arginate and anionic surfactant lysolecithin) on the physical properties, antifungal and mycotoxin inhibitory efficacy of Tween 80 stabilized cinnamon oil-in-water nanoemulsions was investigated.
Condensing-enriched magnetic photonic barcodes on superhydrophobic surface for ultrasensitive multiple detection
Authors: Cai Lijun , Bian Feika , Sun Lingyu , Wang Huan , Zhao Yuanjin
Published: April 2019

When PhC barcodes with stable characteristic reflection peaks are integrated with a superhydrophobic substrate they can realize the ultrasensitive multiple detection by the enrichment of the solution upon evaporation. Thus, the detection of miRNA was carried out by the system and it was found the detection limit was improved by about three orders.
Metabolic responses ofSaccharomyces cerevisiaeto ethanol stress using gas chromatography-mass spectrometry
Authors: Ming Ming , Wang Xiyue , Lian Lili , Zhang Hao , Gao Wenxiu , Zhu Bo , Lou Dawei
Published: April 2019

Metabolic responses ofSaccharomyces cerevisiaeunder ethanol stress by a metabolomics method based on GC-MS.
Single sea urchin–MoO3 nanostructure for surface enhanced Raman spectroscopy of dyes
Authors: Prabhu B Ramya , Bramhaiah K. , Singh Kaushalendra K. , John Neena S.
Published: April 2019

MoO3 micro-nanostructures with a sea urchin morphology are synthesized employing a single-step chemical bath deposition method at lower temperatures. MoO3 sea urchins are non-stoichiometric with oxygen vacancies and surface hydroxyl groups, highly suitable for single nanostructure-based SERS detection of dye molecules.
Synthesis, crystal structures and magnetic properties of a series of pentanuclear heterometallic [CuII3LnIII2] (Ln = Ho, Dy, and Gd) complexes containing mixed organic ligands
Authors: Chen Yong , Long Qiao-Qiao , Hu Zhao-Bo , Wang Hui-Sheng , Huang Zhi-Yong , Chen Wei , Song You , Zhang Zai-Chao , Yang Feng-Jun
Published: April 2019

Three novel heterometallic compounds [CuII3LnIII2] [Ln = Ho (1), Dy (2) and Gd (3)] containing mixed organic ligands were obtained. 1 and 2 show slow magnetic relaxation behaviour.
Optimum selective separation of Cu(ii) using 3D ordered macroporous chitosan films with different pore sizes
Authors: Zhang Yuzhe , Bian Tingting , Xia Da , Wang Dandan , Zhang Yi , Zheng Xudong , Li Zhongyu
Published: April 2019

3DOM-IICF coupled with colloidal crystal template and ion imprinting technology (IIP) was used to absorb copper ions (Cu(ii)) in water. Added polystyrene (PS) micro-spheres to form a three-dimensional ordered macroporous structure.
Graphitic carbon nitride (g-C3N4)/graphite nanocomposite as an extraordinarily sensitive sensor for sub-micromolar detection of oxalic acid in biological samples
Authors: Alizadeh Taher , Nayeri Sahar , Hamidi Negin
Published: April 2019

Nanosized graphitic carbon nitride (nano-g-C3N4) was synthesized using the thermal polymerization of melamine and utilized as a novel electrocatalyst for electrooxidation of oxalic acid (OA).
Anisotropic optical properties induced by uniaxial strain of monolayer C3N: a first-principles study
Authors: Chen Qing-Yuan , Liu Ming-yang , Cao Chao , He Yao
Published: April 2019

The optical properties, structural properties and electronic properties of a new two-dimensional (2D) monolayer C3N under different strains are studied in this paper by using first-principles calculations.
Immobilized antimony species on magnetite: a novel and highly efficient magnetically reusable nanocatalyst for direct and gram-scale reductive-coupling of nitroarenes to azoarenes
Authors: Zeynizadeh Behzad , Faraji Fariba
Published: April 2019

In this study, magnetic nanoparticles of Fe3O4@SbFxwere synthesized. Then, the catalytic activity of Fe3O4@SbFxMNPs was highlighted by one-pot reductive-coupling of aromatic nitro compounds to the corresponding azoarene materials with NaBH4.
Effect of practicum courses on pre-service teachers’ beliefs towards chemistry teaching: a year-long case study
Authors: Boz Yezdan , Ekiz-Kiran Betul , Kutucu Elif Selcan
Published: April 2019

In this study, we examined the effect of School Experience (SE) and Practice Teaching (PT) courses on pre-service chemistry teachers’ beliefs towards chemistry teaching over a one-year period. To reach this purpose, participants’ beliefs and experiences towards chemistry teaching were monitored closely throughout the varied phases of the two practicum courses. Two pre-service chemistry teachers participated in the study. Data were collected via semi-structured interviews, observation notes, CoRes and reflection papers. Semi-structured interviews focusing on the pre-service teachers’ beliefs regarding chemistry teaching were conducted three times while participating in the SE and PT courses. During the PT course before their teaching experiences the participants prepared CoRes, and after their experiences they critiqued their own performances. Moreover, the participants were observed during their student-teaching experiences to identify how they transfer their beliefs into their teaching. Data were analyzed via inductive analyses. Results indicated that both pre-service teachers had stable core beliefs derived from their own experiences as students that remained constant during these courses and guided their practical instruction. Although both participants attended the same courses during the teacher education program, their attitudes while taking the educational courses were different. Factors that shaped pre-service teachers’ beliefs towards teaching were presented as the practicum courses enriched with CoRes and reflection papers, observing their mentors, experiences gained from microteaching sessions, and pedagogical and methods courses taken during the pre-service teacher education program. Implications for the formation of pre-service teachers’ beliefs towards teaching throughout pre-service teacher education programs were provided.
Na2Fe(SO4)2: an anhydrous 3.6 V, low-cost and good-safety cathode for a rechargeable sodium-ion battery
Authors: Pan Wenli , Guan Wenhao , Liu Shuangyu , Xu Ben Bin , Liang Chu , Pan Hongge , Yan Mi , Jiang Yinzhu
Published: April 2019

A new high-voltage earth-abundant cathode for sodium-ion batteries, Na2Fe(SO4)2, is reported, combining high thermal stability and good moisture resistance.
Electronic and optical properties of π-bridged perylenediimide derivatives: the role of π-bridges
Authors: Guo Yuan , Han Guangchao , Tu Zeyi , Yi Yuanping
Published: April 2019

For the π-bridged multi-PDI derivatives, intramolecular electron transfer is dictated by the super-exchange mechanism and can be greatly tuned by the π-bridge modes.
Progress and development in structural and optoelectronic tunability of supramolecular nonbonded fullerene assemblies
Authors: Das Saunak , Presselt Martin
Published: April 2019

Morphology of fullerene assemblies at the few-molecular scale control optoelectronic properties and solar cell parameters at the device scale.
Impressive second harmonic generation response in a novel phase-matchable NLO-active MOF derived from achiral precursors
Authors: Zhang Yu-Xiao , Li Bing-Xuan , Lin Hua , Ma Zuju , Wu Xin-Tao , Zhu Qi-Long
Published: April 2019

Simple yet extraordinary: a novel 1D Zn-based MOF with promising nonlinear optical (NLO) response has been prepared from achiral precursors, which serves as a prototype to theoretically access insight into the origin of the NLO response.
Genomic testing, tumor microenvironment and targeted therapy of Hedgehog-related human cancers
Authors: Katoh Masaru
Published: April 2019

Hedgehog signals are transduced through Patched receptors to the Smoothened (SMO)-SUFU-GLI and SMO-Gi-RhoA signaling cascades. MTOR-S6K1 and MEK-ERK signals are also transduced to GLI activators through post-translational modifications. The GLI transcription network up-regulates target genes, such as BCL2, FOXA2, FOXE1, FOXF1, FOXL1, FOXM1, GLI1, HHIP, PTCH1 and WNT2B, in a cellular context-dependent manner. Aberrant Hedgehog signaling in tumor cells leads to self-renewal, survival, proliferation and invasion. Paracrine Hedgehog signaling in the tumor microenvironment (TME), which harbors cancer-associated fibroblasts, leads to angiogenesis, fibrosis, immune evasion and neuropathic pain. Hedgehog-related genetic alterations occur frequently in basal cell carcinoma (BCC) (85%) and Sonic Hedgehog (SHH)-subgroup medulloblastoma (87%) and less frequently in breast cancer, colorectal cancer, gastric cancer, pancreatic cancer, non-small-cell lung cancer (NSCLC) and ovarian cancer. Among investigational SMO inhibitors, vismodegib and sonidegib are approved for the treatment of patients with BCC, and glasdegib is approved for the treatment of patients with acute myeloid leukemia (AML). Resistance to SMO inhibitors is caused by acquired SMO mutations, SUFU deletions, GLI2 amplification, other by-passing mechanisms of GLI activation and WNT/β-catenin signaling activation. GLI–DNA-interaction inhibitors (glabrescione B and GANT61), GLI2 destabilizers (arsenic trioxide and pirfenidone) and a GLI-deacetylation inhibitor (4SC-202) were shown to block GLI-dependent transcription and tumorigenesis in preclinical studies. By contrast, SMO inhibitors can remodel the immunosuppressive TME that is dominated by M2-like tumor-associated macrophages (M2-TAMs), myeloid-derived suppressor cells and regulatory T cells, and thus, a Phase I/II clinical trial of the immune checkpoint inhibitor pembrolizumab with or without vismodegib in BCC patients is ongoing.
Energy extraction properties of a flapping wing with a deformable airfoil
Authors: Zhu Bing , Zhang Wei , Huang Yun
Published: April 2019

Flapping wing devices have attracted considerable attention as a new means of power extraction. The present study applies transient numerical calculations based on the dynamic mesh technique to investigate the influences of leading edge, trailing edge, or overall circular arc airfoil deformations on the power extraction efficiencies of a flapping wing device under the condition of maintaining a constant arc length along the mean camber line of the foil. The results indicate that airfoil deformations can improve the power extraction efficiency of the flapping wing device. The primary reason is that the active synchronised deformation of the foil increases the effective curvature and the velocity circulation around the foil. In addition, the performance curve of the flapping wing device exhibits two frequency ranges with relative high efficiency. In the low frequency region, if the leading edge vortex (LEV) detaches from the trailing edge just as the foil reverses its heaving direction, the foil will gain much more energy due to the positive power extraction of the pitching moment. In the high frequency region, a small steady body‐attached vortex (BAV) maintains a high lift, and, thus, the device extracts more power due to the enhanced heaving force.
Two‐stage op‐amp and integrator realisation through GaAsP/AlGaSb nanowire CP‐TFET
Authors: Lemtur Alemienla , Sharma Dheeraj , Patel Jyoti , Suman Priyanka , Rajan Chithraja
Published: April 2019

Tunnel field effect transistors (TFETs) have been extensively explored for the possibility of replacing metal oxide semiconductor FET (MOSFET) due to its steeper slope and for being more energy efficient. In this regard, device level performance of AlGaSb/GaAsP gate all around (Nanowire) charge plasma TFET (CP‐TFET) shows promising results. To further verify these results, an overview of circuit performance is provided in this work, where analysis of two‐stage operational amplifier (op‐amp) is shown. Further, based on this op‐amp, working of the integrator is also demonstrated. Simulations are carried out with the aid of Verilog A model in the Cadence environment. The outcome of circuit performance exhibits that the proposed device is viable for analogue applications and can be seriously considered for future low‐power analogue designs.
Tight‐binding model for the electronic properties of buckled triangular borophene
Authors: Horri Ashkan , Faez Rahim
Published: April 2019

In this work, the authors present a tight‐binding (TB) model for describing the electronic properties of buckled triangular Borophene. This TB model is constructed using three orbitals for each boron atom. The Slater–Koster approach is applied to calculate TB Hamiltonian. Parameters of the TB model are fitted from the first‐principle energy band results. When only nearest‐neighbour hoppings are included, this TB model is sufficient to capture the bands around high‐symmetry k ‐points.
Stellar activity and rotation of the planet host Kepler-17 from long-term space-borne photometry
Authors: Lanza A. F. , Netto Y. , Bonomo A. S. , Parviainen H. , Valio A. , Aigrain S.
Published: April 2019

Context. The study of young Sun-like stars is fundamental to understanding the magnetic activity and rotational evolution of the Sun. Space-borne photometry by the Kepler telescope provides unprecedented datasets to investigate these phenomena in Sun-like stars.

Aims. We present a new analysis of the entire Kepler photometric time series of the moderately young Sun-like star Kepler-17 accompanied by a transiting hot Jupiter.

Methods. We applied a maximum-entropy spot model to the long-cadence out-of-transit photometry of the target to derive maps of the starspot filling factor versus the longitude and the time. These maps are compared to the spots occulted during transits to validate our reconstruction and derive information on the latitudes of the starspots.

Results. We find two main active longitudes on the photosphere of Kepler-17, one of which has a lifetime of at least ∼1400 days although with a varying level of activity. The latitudinal differential rotation is of solar type, that is, with the equator rotating faster than the poles. We estimate a minimum relative amplitude ΔΩ/Ω between ∼0.08 ± 0.05 and 0.14 ± 0.05, our determination being affected by the finite lifetime of individual starspots and depending on the adopted spot model parameters. We find marginal evidence of a short-term intermittent activity cycle of ∼48 days and an indication of a longer cycle of 400−600 days characterized by an equatorward migration of the mean latitude of the spots as in the Sun. The rotation of Kepler-17 is likely to be significantly affected by the tides raised by its massive close-by planet.

Conclusion. We confirm the reliability of maximum-entropy spot models to map starspots in young active stars and characterize the activity and differential rotation of this young Sun-like planetary host.
Phase-curve analysis of comet 67P/Churyumov-Gerasimenko at small phase angles
Authors: Masoumzadeh N , Kolokolova L , Tubiana C , El-Maarry M. R. , Mottola S , Güttler C. , Snodgrass C , Sierks H. , Naletto G. , Lamy P. L. , Rodrigo R. , Koschny D , Davidsson B , Barucci M. A. , Bertaux J.-L. , Bertini I , Bodewits D. , Cremonese G , Da Deppo V. , Debei S. , De Cecco M. , Deller J. , Fornasier S. , Fulle M , Gutiérrez P. J. , Hasselmann P. H. , Ip W.-H. , Keller H. U. , Lara L. M. , Lazzarin M , López-Moreno J. J. , Marzari F , Shi X , Toth I
Published: April 2019

Aims. The Rosetta-OSIRIS images acquired at small phase angles in three wavelengths during the fly-by of the spacecraft on 9–10 April 2016 provided a unique opportunity to study the opposition effect on the surface of comet 67P/Churyumov-Gerasimenko (67P). Our goal is to study phase curves of the nucleus at small phase angles for a variety of surface structures to show the differences in their opposition effect and to determine which surface properties cause the differences.

Methods. We used OSIRIS NAC images that cover the Ash-Khepry-Imhotep region to extract the phase curve, that is, the reflectance of the surface as a function of phase angle. We selected six regions of interest (ROIs) and derived the phase curves for each ROI. We fit a linear-exponential function to the phase curves. The resulting model parameters were then interpreted by spectrophotometric, geomorphological, and phase-ratio analyses, and by investigating the influence of structural and textural properties of the surface.

Results. We find evidence for the opposition effect (deviation of the phase curve from linear behavior) in phase curves for all areas. We found an anticorrelation between the phase ratio and reflectance in a small phase angle range. This provides evidence for the shadow-hiding effect. We conclude that the decrease in the slope of the phase ratio versus reflectance indicates a decrease in the proportion of shadowed regions and reduces the contribution of the shadow-hiding effect. Large uncertainties in the determination of the opposition effect parameters with respect to wavelength do not allow us to conclusively claim coherent backscattering in the opposition effect phenomenon. Based on the two analyses, we conclude that the opposition effect of comet 67P in the Ash-Khepry-Imhotep region is mainly affected by shadow-hiding.
Physical and chemical fingerprint of protostellar disc formation
Authors: Artur de la Villarmois E. , Jørgensen J. K. , Kristensen L. E. , Bergin E. A. , Harsono D. , Sakai N. , van Dishoeck E. F. , Yamamoto S.
Published: April 2019

Context. The structure and composition of emerging planetary systems are likely strongly influenced by their natal environment within the protoplanetary disc at the time when the star is still gaining mass. It is therefore essential to identify and study the physical processes at play in the gas and dust close to young protostars and investigate the chemical composition of the material that is inherited from the parental cloud.

Aims. The purpose of this paper is to explore and compare the physical and chemical structure of Class I low-mass protostellar sources on protoplanetary disc scales.

Methods. We present a study of the dust and gas emission towards a representative sample of 12 Class I protostars from the Ophiuchus molecular cloud with the Atacama Large Millimeter/submillimeter Array (ALMA). The continuum at 0.87 mm and molecular transitions from C17O, C34S, H13CO+, CH3OH, SO2, and C2H were observed at high angular resolution (0.′′4, ~60 au diameter) towards each source. The spectrally and spatially resolved maps reveal the kinematics and the spatial distribution of each species. Moreover, disc and stellar masses are estimated from the continuum flux and position-velocity diagrams, respectively.

Results. Six of the sources show disc-like structures in C17O, C34S, or H13CO+ emission. Towards the more luminous sources, compact emission and large line widths are seen for transitions of SO2 that probe warm gas (Eu ~ 200 K). In contrast, C17O emission is detected towards the least evolved and less luminous systems. No emission of CH3OH is detected towards any of the continuum peaks, indicating an absence of warm CH3OH gas towards these sources.

Conclusions. A trend of increasing stellar mass is observed as the envelope mass decreases. In addition, a power-law relation is seen between the stellar mass and the bolometric luminosity, corresponding to a mass accretion rate of (2.4 ± 0.6) × 10−7 M⊙ yr−1 for the Class I sources, with a minimum and maximum value of 7.5 × 10−8 and 7.6 × 10−7 M⊙ yr−1, respectively. This mass accretion rate is lower than the expected value if the accretion is constant in time and rather points to a scenario of accretion occurring in bursts. The differentiation between C17O and SO2 suggests that they trace different physical components: C17O traces the densest and colder regions of the disc-envelope system, while SO2 may be associated with regions of higher temperature, such as accretion shocks. The lack of warm CH3OH emission suggests that there is no hot-core-like region around any of the sources and that the CH3OH column density averaged over the disc is low. Finally, the combination of bolometric temperature and luminosity may indicate an evolutionarytrend of chemical composition during these early stages.