bluuebunny/crossref_metadata_2025 huggingface dataset:
Upconversion photoluminescence of Ho3+-Yb3+ doped barium titanate nanocrystallites: Optical tools for structural phase detection and temperature probing
Authors: Mahata Manoj Kumar , Koppe Tristan , Kumar Kaushal , Hofsäss Hans , Vetter Ulrich
Published: May 2020

Authors have explored the photo-physical properties of Ho3+-Yb3+ doped BaTiO3 nanocrystals and proposed an intuitive method to probe temperature and crystal phase structure of the matrix. Structural phase change of doped crystals was analyzed in terms of their X-ray diffraction, and it was confirmed through second harmonic generation. We give insights on upconversion of energy of light-emission in Ho3+-Yb3+: BaTiO3 nanocrystals upon a 980 nm laser-light excitation and subsequently, the excited state dynamics were studied with the help of dependence of upconversion luminescence on excitation power and measuring-temperature. To understand the nature of occupancies of the Ho3+ ions at the Ti- and Ba-sites, we performed site-selective, time-resolved spectroscopic measurements at various crystal phases. Based on the lifetime analysis, it is inferred that the Ho3+ ions are present at two types of sites in barium titanate lattice. One of those is the 6-coordinated Ti-site of low symmetry, while the other one is the 12-coordinated Ba-site of higher symmetry. The upconversion emission of the nanocrystals are found to be temperature-sensitive (12 to 300 K), indicating possible use as a self-referenced temperature probe. An analysis of the temperature dependent emissions from 5F4 and 5S2 levels of Ho3+ ions, gives a maximum value of temperature sensitivity ~ 0.0095 K−1 at 12 K. Furthermore, we observe a sharp change in the luminescence intensity at ~180 K due to a ferroelectric phase change of the sample. The correlation of upconversion luminescence with the results of X-ray diffraction and second harmonic generation at different crystal phases implies that the frequency upconversion may be used as a probe of structural change of the lattice.
The Effects of Tetracycline Residues on the Microbial Community Structure of Tobacco Soil in Pot Experiment
Authors: Zheng Jiayu , Zhang Jixu , Gao Lin , Kong Fanyu , Shen Guoming , Wang Rui , Gao Jiaming , Zhang Jiguang
Published: May 2020

To evaluate the micro-ecological effects of tetracycline residues on tobacco soil, high-throughput sequencing technology was used to study the effects of the addition of different concentrations (0, 5, 50, and 500 mg·kg−1) of tetracycline on the abundance, diversity, and structure of bacterial and fungal communities in the rhizosphere and non-rhizosphere soil of flue-cured tobacco in China. Results showed that the presence of tetracycline had an important but varying effect on soil bacterial and fungal community richness, diversity, and structure. Changes in the diversity indices (Chao index and Shannon index) of soil bacterial and fungal communities showed a similar pattern after the addition of tetracycline; however, a few differences were found in the effects of tetracycline in the rhizosphere and non-rhizosphere soil, suggesting an evident rhizosphere-specific effect. The bacterial community at the phylum level in the rhizosphere closely clustered into one group, which might be the result of tobacco root secretions and rhizodeposition. Tetracycline showed a concentration-dependent effect on the soil bacterial community structure. The soil bacterial community structures observed after treatments with higher concentrations of tetracycline (50 and 500 mg·kg−1) were found to be closely related. Moreover, the effects of the treatments with higher concentrations of tetracycline, on the soil bacterial community at the phylum level, were different from those with lower concentrations of tetracycline (5 mg·kg−1), and CK treatments. This might have resulted from the induction of increasing selective pressure with increasing antibiotic concentration. Tetracycline continued to affect the soil bacterial community throughout the experiment. Tetracycline was found to have a varying impact on the community structure of soil fungi compared to that of soil bacteria, and the addition of an intermediate concentration of tetracycline (50 mg·kg−1) significantly increased the soil fungal diversity in the non-rhizosphere soil. The biological effects of tetracycline on the soil fungal community and the fungal-bacterial interactions, therefore, require further elucidation, warranting further research.
Near IR responsive targeted integrated lipid polymer nanoconstruct for enhanced magnolol cytotoxicity in breast cancer
Authors: Elhabak Mona , Osman Rihab , Mohamed Mona , El-Borady Ola M. , Awad Gehanne A. S. , Mortada Nahed
Published: May 2020

Advances in cancer nanotechnology aim at improving specificity and effectiveness for tumor treatment. Amalgamation of different treatment modalities is expected to provide better cancer combating. Herein, We developed a long circulating nanocarrier comprising trastuzumab (TZB) surface modified polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) co-encapsulating magnolol (Mag) and gold nanoparticles (GNPs). A modified single step nanoprecipitation method was adopted ensuring particle coating with D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) while co-encapsulating GNPs. TZB was then anchored on NPs surface using a carbodiimide chemistry. The cytotoxicity of the developed system was evaluated with and without photothermal irradiation. NPs cellular uptake was then followed using confocal microscopical imaging. A hybrid matrix composed of PLGA/TPGS and surface decorated with TZB with a conjugation efficiency of ˃65%, was confirmed via FTIR, 1HNMR. GNPs could only be included in the NPs, when placed in the organic phase as evidenced by the shifted GNPs surface plasmonic resonance and confirmed via imaging coupled with energy dispersive X-ray analysis. Optimized NPs (136.1 ± 1.3 nm, −8.2 ± 1 mV and Mag encapsulation efficiency of 81.4 ± 1.8%) were able to boost Mag cytotoxicity on breast cancer cells while providing a selective multifunctional therapy with an added photothermal effect.
Beneficial effects of benzodiazepine on masticatory muscle dysfunction induced by chronic stress and occlusal instability in an experimental animal study
Authors: Nascimento Glauce C. , Malzone Bruno L. , Iyomasa Daniela M. , Pereira Yamba C. L. , Issa João Paulo M. , Leite-Panissi Christie R. A. , Watanabe Ii-Sei , Iyomasa Mamie M. , Fuentes Ramon , Del Bel Elaine , Dias Fernando J.
Published: May 2020

Psychological stress and occlusal alteration are important etiologic factors for temporomandibular/masticatory muscular disorders. In particular, the exact physiologic mechanism underlying the relation by occlusal alteration and temporomandibular disorders remains unclear. Our purpose was to test the hypothesis that benzodiazepine therapy is able to prevent metabolic and vascular changes in the medial pterygoid muscle of rats under chronic stress after 14 days of unilateral exodontia. Adult Wistar rats were submitted to unpredictable chronic mild stress (10 days) and/or unilateral exodontia and their plasma and medial pterygoid muscles were removed for analysis. A pre-treatment with diazepam was used to verify its effect on stress. The parameters evaluated included anxiety behavior, plasma levels of corticosterone, metabolic activity by succinate dehydrogenase, capillary density by laminin staining and ultrastructural findings by transmission electron microscopy. Occlusal instability induced anxiety-like behavior on elevated plus-maze test and diazepam administration blocked the appearance of this behavior. Unilateral exodontia promoted in the contralateral muscle an increase of oxidative fibers and capillaries and modification of sarcoplasmic reticulum. Chronic stress caused increased glycolytic metabolism, reduced capillary density and morphological changes in mitochondria on both sides. Association of both factors induced a glycolytic pattern in muscle and hemodynamic changes. Pharmacological manipulation with diazepam inhibited the changes in the medial pterygoid muscle after stress. Our results reveal a preventive benzodiazepine treatment for stress and occlusal instability conditions affecting masticatory muscle disorders. In addition, provide insights into the mechanisms by which chronic stress and exodontia might be involved in the pathophysiology of masticatory muscular dysfunctions.
Inbred varieties outperformed hybrid rice varieties under dense planting with reducing nitrogen
Authors: Lu Jian , Wang Danying , Liu Ke , Chu Guang , Huang Liying , Tian Xiaohai , Zhang Yunbo
Published: May 2020

Field experiments were conducted over two years to evaluate the effects of planting density and nitrogen input rate on grain yield and nitrogen use efficiency (NUE) of inbred and hybrid rice varieties. A significant interaction effect was observed between nitrogen input and planting density on grain yield. Higher number of panicles per square meter and spikelets per panicle largely accounted for the observed advantage in performance of inbred, relative to hybrid varieties. Compared with high nitrogen input rate, nitrogen absorption efficiency, nitrogen recovery efficiency, and partial factor productivity increased by 24.6%, 28.0%, and 33.3% in inbred varieties, and by 32.2%, 29.3%, and 35.0% in hybrids under low nitrogen input, respectively. Inbred varieties showed higher nitrogen absorption efficiency, nitrogen recovery efficiency, and partial factor productivity than hybrids, regardless of nitrogen input level. Nitrogen correlated positively with panicle number, spikelets per panicle, biomass production at flowering, and after flowering in inbred varieties but only with panicle number and biomass production at flowering in hybrids. Inbred varieties are more suitable for high planting density at reduced nitrogen input regarding higher grain yield and NUE. These findings bear important implications for achieving high yield and high efficiency in nutrient uptake and utilization in modern rice-production systems.
Dynamic Effects of Aortic Arch Stiffening on Pulsatile Energy Transmission to Cerebral Vasculature as A Determinant of Brain-Heart Coupling
Authors: Aghilinejad Arian , Amlani Faisal , King Kevin S. , Pahlevan Niema M.
Published: May 2020

Aortic stiffness increases with age and is a robust predictor of brain pathology including Alzheimer’s and other dementias. Aging causes disproportionate stiffening of the aorta compared with the carotid arteries, reducing protective impedance mismatches at their interface and affecting transmission of destructive pulsatile energy to the cerebral circulation. Recent clinical studies have measured regional stiffness within the aortic arch using pulse wave velocity (PWV) and have found a stronger association with cerebrovascular events than global stiffness measures. However, effects of aortic arch PWV on the transmission of harmful excessive pulsatile energy to the brain is not well-understood. In this study, we use an energy-based analysis of hemodynamic waves to quantify the effect of aortic arch stiffening on transmitted pulsatility to cerebral vasculature, employing a computational approach using a one-dimensional model of the human vascular network. Results show there exists an optimum wave condition—occurring near normal human heart rates—that minimizes pulsatile energy transmission to the brain. This indicates the important role of aortic arch biomechanics on heart-brain coupling. Our results also suggest that energy-based indices of pulsatility combining pressure and flow data are more sensitive to increased stiffness than using flow or pressure pulsatility indices in isolation.
TRPV1 is crucial for thermal homeostasis in the mouse by heat loss behaviors under warm ambient temperature
Authors: Yonghak Park , Miyata Seiji , Kurganov Erkin
Published: May 2020

Thermal homeostasis in mammalians is a self-regulating process by which biological systems maintain an internal thermal stability, even under different temperature conditions; however, the molecular mechanisms involved under warm ambient temperature remain unclear. Here, we aimed to clarify functional significance of transient receptor potential vanilloid receptor 1 (TRPV1) under warm ambient temperature. TRPV1 KO mice exhibited transient hyperthermia when exposed to 30.0 and 32.5 °C, whereas wild-type (WT) mice did not. TRPV1 KO mice exhibited prolonged and prominent hyperthermia upon exposure to 35.0 °C, whereas WT mice showed transient hyperthermia. Hyperthermia also occurs in WT mice that received intracerebroventricular injection of TRPV1 antagonist AMG9810 upon exposure to 35.0 °C. Heat loss behaviors, sleeping and body licking, were deficient in TRPV1 KO mice exposed to warm temperatures. Therefore, the present results indicate that central TRPV1 is crucial for maintaining a constant body temperature via the initiation of heat loss behaviors under warm ambient temperature.
Morphological changes in the subthalamic nucleus of people with mild-to-moderate Parkinson’s disease: a 7T MRI study
Authors: Patriat Rémi , Niederer Jacob , Kaplan Jordan , Amundsen Huffmaster Sommer , Petrucci Matthew , Eberly Lynn , Harel Noam , MacKinnon Colum
Published: May 2020

This project investigated whether structural changes are present in the subthalamic nucleus (STN) of people with mild-to-moderate severity of Parkinson’s disease (PD). Within-subject measures of STN volume and fractional anisotropy (FA) were derived from high-resolution 7Tesla magnetic resonance imaging (MRI) for 29 subjects with mild-to-moderate PD (median disease duration = 2.3±1.9 years) and 18 healthy matched controls. Manual segmentation of the STN was performed on 0.4 mm in-plane resolution images. FA maps were generated and FA values were averaged over the left and right STN separately for each subject. Motor sign severity was assessed using the Movement Disorders Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). Linear effects models showed that STN volume was significantly smaller in the PD subjects compared to controls (p = 0.01). Further, after controlling for differences in STN volumes within or between groups, the PD group had lower FA values in the STN compared to controls (corrected p ≤ 0.008). These findings demonstrate that morphological changes occur in the STN, which likely impact the function of the hyperdirect and indirect pathways of the basal ganglia and movement control.
Spatio-temporal patterning of different connexins in developing and postnatal human kidneys and in nephrotic syndrome of the Finnish type (CNF)
Authors: Kosovic Ivona , Filipovic Natalija , Benzon Benjamin , Vukojevic Katarina , Saraga Marijan , Glavina Durdov Merica , Bocina Ivana , Saraga-Babic Mirna
Published: May 2020

Connexins (Cxs) are membrane-spanning proteins which enable flow of information important for kidney homeostasis. Changes in their spatiotemporal patterning characterize blood vessel abnormalities and chronic kidney diseases (CKD). We analysed spatiotemporal expression of Cx37, Cx40, Cx43 and Cx45 in nephron and glomerular cells of developing, postnatal kidneys, and nephrotic syndrome of the Finnish type (CNF) by using immunohistochemistry, statistical methods and electron microscopy. During kidney development, strong Cx45 expression in proximal tubules and decreasing expression in glomeruli was observed. In developing distal nephron, Cx37 and Cx40 showed moderate-to-strong expression, while weak Cx43 expression gradually increased. Cx45/Cx40 co-localized in mesangial and granular cells. Cx43 /Cx45 co-localized in podocytes, mesangial and parietal epithelial cells, and with podocyte markers (synaptopodin, nephrin). Different Cxs co-expressed with endothelial (CD31) and VSMC (α –SMA) markers in vascular walls. Peak signalling of Cx37, Cx43 and Cx40 accompanied kidney nephrogenesis, while strongest Cx45 signalling paralleled nephron maturation. Spatiotemporal Cxs patterning indicate participation of Cx45 in differentiation of proximal tubules, and Cx43, Cx37 and Cx40 in distal tubules differentiation. CNF characterized disorganized Cx45 expression in proximal tubules, increased Cx43 expression in distal tubules and overall elevation of Cx40 and Cx37, while Cx40 co-localized with increased number of interstitial myofibroblasts.
Efficacy of conbercept combined with panretinal photocoagulation in the treatment of proliferative diabetic retinopathy
Authors: He Feng , Yang Jingyun , Zhang Xiao , Yu Weihong
Published: May 2020

This prospective clinical study was to compare the effect of panretinal photocoagulation (PRP) associated with intravitreal conbercept injections versus PRP alone in the treatment of proliferative diabetic retinopathy (PDR). For each of 15 patients included, one eye was randomly assigned to receive treatment with PRP, and the other eye received conbercept combined PRP. Ophthalmic examinations, optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) were performed at baseline and at each monthly visit until 6 months. Fluorescein angiography (FA) was acquired at baseline, 3 months and 6 months. Between group and within group analysis was done by using generalized estimating equations (GEE). The combination group had a significant decrease of neovascularization (NV) leakage area than the PRP group at month 3 and month 6 after treatment, and a better best-corrected visual acuity (BCVA) during the first three months. Within-group analysis indicated a significant decrease in NV leakage at month 3 and month 6 in both groups, and a significant increase in BCVA at 1 month in the combination group. In summary, the combination of intravitreal injection of conbercept and PRP can significantly reduce the NV of PDR patients and achieve better BCVA during the drug’s lifespan compared with PRP alone.
Anguillid eels as a surrogate species for conservation of freshwater biodiversity in Japan
Authors: Itakura Hikaru , Wakiya Ryoshiro , Gollock Matthew , Kaifu Kenzo
Published: May 2020

To monitor and manage biodiversity, surrogate species (i.e., indicator, umbrella and flagship species) have been proposed where conservation resources are focused on a limited number of focal organisms. Using data obtained from 78 sites across six rivers in the mainland Japan and the Amami-Oshima Island, we demonstrate that two anguillids – the Japanese eel (Anguilla japonica) and the giant mottled eel (A. marmorata) – can act as surrogate species for conservation of freshwater biodiversity. Anguillid eels were the widest topographically-distributed species ranging from near the mouth to the upper reaches of rivers. Moreover, stable isotopic analyses indicated that eels are likely one of the highest-order predators in freshwater ecosystems. A significant positive relationship was found between the density of eels and the number of other diadromous species collected. However, the optimal models revealed that both the density of eels and the number of other diadromous species were significantly negatively correlated with distance from the river mouth and cumulative height of trans-river structures from the river mouth to each site. This suggests the positive relationship between eel density and number of other diadromous species was indirect and related to river-ocean connectivity. Given their catadromous life-cycle, and global commercial and cultural importance, as a taxa, anguillid eels can act as indicator, umbrella and flagship species, and a comprehensive surrogate for conservation of freshwater biodiversity.
Root growth in light of changing magnesium distribution and transport between source and sink tissues in potato (Solanum tuberosum L.)
Authors: Koch Mirjam , Winkelmann Merle Katharina , Hasler Mario , Pawelzik Elke , Naumann Marcel
Published: May 2020

This study depicts relations between magnesium (Mg) transport and re-translocation, photoassimilate partitioning, cation and ion concentrations, and finally root growth of potato under different Mg supplies. Potato plants were grown in a hydroponic culture system under different Mg regimes while investigating Mg concentrations, the expression of various Mg transporters, soluble sugars, and cations and anions in source and sink organs at different growth stages. Reports from literature about the impact of Mg deficiency on root growth are inconsistent. As Mg is known to be a phloem mobile nutrient, it is expected to be re-translocated under restricted availability of Mg from source to sink organs. Thus, we assume that plants can tolerate a slight Mg restriction without severe root growth reduction. However, under severe Mg deficiency, the process of Mg re-translocation is hampered, resulting in an impaired photoassimilate partitioning, and finally root growth. This might also explain the findings of studies claiming that Mg deficiency does not impair root growth as plants of these studies likely only suffered a slight Mg restriction. Finally, this study gives indications that an interruption of the process of Mg-re-translocation in early plant growth could be an indicator for growth reductions of the plant at a later growth stage.
N-Terminal selective modification of peptides and proteins using 2-ethynylbenzaldehydes
Authors: Deng Jie-Ren , Lai Nathanael Chun-Him , Kung Karen Ka-Yan , Yang Bin , Chung Sai-Fung , Leung Alan Siu-Lun , Choi Man-Chung , Leung Yun-Chung , Wong Man-Kin
Published: May 2020

Selective modification of the N-terminus of peptides and proteins is a promising strategy for single site modification methods. Here we report N-terminal selective modification of peptides and proteins by using 2-ethynylbenzaldehydes (2-EBA) for the production of well-defined bioconjugates. After reaction screening with a series of 2-EBA, excellent N-terminal selectivity is achieved by the reaction in slightly acidic phosphate-buffered saline using 2-EBA with electron-donating substituents. Selective modification of a library of peptides XSKFR (X = either one of 20 natural amino acids) by 2-ethynyl-4-hydroxy-5-methoxybenzaldehyde (2d) results in good-to-excellent N-terminal selectivity in peptides (up to >99:1). Lysozyme, ribonuclease A and a therapeutic recombinant Bacillus caldovelox arginase mutant (BCArg mutant) are N-terminally modified using alkyne- and fluorescein-linked 2-EBA. Alkyne-linked BCArg mutant is further modified by rhodamine azide via copper(I)-catalyzed [3 + 2] cycloaddition indicating that the reaction has high functional group compatibility. Moreover, the BCArg mutant modified by 2-ethynyl-5-methoxybenzaldehyde (2b) exhibits comparable activity in enzymatic and cytotoxic assays with the unmodified one.
Comment on “ferroelectricity-free lead halide perovskites” by A. Gómez, Q. Wang, A. R. Goñi, M. Campoy-Quiles and A. Abate, Energy Environ. Sci., 2019, 12, 2537
Authors: Colsmann Alexander , Leonhard Tobias , Schulz Alexander D. , Röhm Holger
Published: May 2020

This comment analyzes pitfalls when investigating piezoresponse and ferroelectricity in organic-metal halide perovskite thin films.
Biological effects of allergen–nanoparticle conjugates: uptake and immune effects determined on hAELVi cells under submerged vs. air–liquid interface conditions
Authors: Mills-Goodlet Robert , Schenck Milena , Chary Aline , Geppert Mark , Serchi Tommaso , Hofer Sabine , Hofstätter Nobert , Feinle Andrea , Hüsing Nicola , Gutleb Arno C. , Himly Martin , Duschl Albert
Published: May 2020

An allergen–nanoparticle interaction study was performed using hAELVi cells grown under submerged vs. air–liquid interface culture conditions. Choice of cellular models showed impact on the investigation of uptake kinetics and inflammatory responses.
Dual switchable molecular tweezers incorporating anisotropic MnIII–salphen complexes
Authors: Doistau Benjamin , Benda Lorien , Cantin Jean-Louis , Cador Olivier , Pointillart Fabrice , Wernsdorfer Wolfgang , Chamoreau Lise-Marie , Marvaud Valérie , Hasenknopf Bernold , Vives Guillaume
Published: May 2020

Molecular tweezers incorporating Mn(III)–salphen complexes were synthesized and closed by the orthogonal mechanism (Zn(II) coordination and cyanide binding) resulting in a switch of magnetic properties.
Correction: Computer-aided design of high-efficiency GeTe-based thermoelectric devices
Authors: Hong Min , Zheng Kun , Lyv Wanyu , Li Meng , Qu Xianlin , Sun Qiang , Xu Shengduo , Zou Jin , Chen Zhi-Gang
Published: May 2020

Correction for ‘Computer-aided design of high-efficiency GeTe-based thermoelectric devices’ by Min Hong et al., Energy Environ. Sci., 2020, DOI: 10.1039/d0ee01004a.
Determination of oxoanions and water-soluble species of arsenic, selenium, antimony, vanadium, and chromium eluted in water from airborne fine particles (PM2.5): effect of acid and transition metal content of particles on heavy metal elution
Authors: Taira Misaki , Sakakibara Kunio , Saeki Kentaro , Ohira Shin-Ichi , Toda Kei
Published: May 2020

Leaching of toxic heavy metal oxoanions from PM2.5 is related to acids and transition metals of PM2.5.
Reaction of ketone hydrazones with TeCl4: isolation and reactions of novel divinyl telluride
Authors: Okuma Kentaro , Qu Yuxuan , Suetome Aoi , Nagahora Noriyoshi
Published: May 2020

The reaction of acetophenone hydrazones with TeCl4 in the presence of DBU gave divinyl tellurides. The reaction of divinyl tellurides with bromine or benzyne afforded the corresponding tellurium dibromides or (E)-2-alkenyl tellurides.
Covalent interactions depend on the distances between metals and fullerenes for thermodynamically stable M@C78 (M = La, Ce, and Sm)
Authors: Li Mengyang , Zhao Yaoxiao , Han Yanbo , Yuan Kun , Zhang Kaini , Chen Yingqi , Ehara Masahiro , Nagase Shigeru , Zhao Xiang
Published: May 2020

Thermodynamic selectivity occurs between fullerenes and metals in M@C78 (M = La, Ce, Sm), including non-IPR C1(22 595)-C78; the different number of electrons transferred from metals to C78 leads to the first EMF with diradical features.
Rapid, ultrasensitive and highly specific biosensor for the diagnosis of SARS-CoV-2 in clinical blood samples
Authors: Zeng Lu , Li Yue , Liu Jie , Guo Lingling , Wang Zhongxing , Xu Xinxin , Song Shanshan , Hao Changlong , Liu Liqiang , Xin Meiguo , Xu Chuanlai
Published: May 2020

IgG–IgM immunochromatographic strip for rapid screening of SARS-CoV-2 infection including confirmed patients, suspect and asymptomatic carriers in 15 min.
Combined KH/alkaline-earth metal amide catalysts for hydrogenation of alkenes
Authors: Zhang Xiang-Yu , Du Hui-Zhen , Zhai Dan-Dan , Guan Bing-Tao
Published: May 2020

Breaking saline KH: The combined KH/alkaline-earth metal amide catalysts display much better catalytic activity than their components in the hydrogenation of alkenes, suggesting the degradation and activation of saline KH with the metal amides.
Pd/Xiang-Phos-catalyzed enantioselective intermolecular carboheterofunctionalization under mild conditions
Authors: Tao Mengna , Tu Youshao , Liu Yu , Wu Haihong , Liu Lu , Zhang Junliang
Published: May 2020

A highly chemo-, regio-, enantio-selectivitive Pd/Xiang-Phos-catalyzed intermolecular carboheterofunctionalization of 2,3-dihydrofurans for the synthesis of polysubstituted benzofused heterocycles mild conditions.
Statistical mechanical analysis of the electromechanical coupling in an electrically-responsive polymer chain
Authors: Grasinger Matthew , Dayal Kaushik
Published: May 2020

Polymers that couple deformation and electrostatics have potential application in soft sensors and actuators for robotics and biomedical technologies. This paper applies statistical mechanics to study their coupled electromechanical response.
Inverse and highly selective separation of CO2/C2H2on a thulium–organic framework
Authors: Ma Deyun , Li Zhi , Zhu Jiaxing , Zhou Yiping , Chen Lilin , Mai Xufeng , Liufu Meilin , Wu Yinbing , Li Yingwei
Published: May 2020

A new Tm-based complex1is synthesized and activated at different temperatures to obtain two porous MOFs (1aand1a′) with different pore sizes and pore surfaces, in which1ashows an excellent capability to selectively capture CO2from CO2/C2H2.
Efficient modelling of ion structure and dynamics in inorganic metal halide perovskites
Authors: Balestra Salvador R. G. , Vicent-Luna Jose Manuel , Calero Sofia , Tao Shuxia , Anta Juan A.
Published: May 2020

Inorganic metal halide perovskites are nowadays one of the most studied semiconductors. Using quantum calculations as reference data, we have employed a genetic algorithm to develop a force field to study ion migrations and lattice dynamics.
Optimization of analytical assay performance of antibody-gated indicator-releasing mesoporous silica particles
Authors: Costa Elena , Climent Estela , Gawlitza Kornelia , Wan Wei , Weller Michael G. , Rurack Knut
Published: May 2020

An in-depth study of the chemical tuning modes of antibody-gated indicator delivery (gAID) systems revealed the importance of size matching, localisation of grafting and loading sequence for obtaining high-performance small-molecule sensor materials.
Ultra-high lattice thermal conductivity and the effect of pressure in superhard hexagonal BC2N
Authors: Nayeb Sadeghi Safoura , Vaez Allaei S. Mehdi , Zebarjadi Mona , Esfarjani Keivan
Published: May 2020

Using first-principles methods to calculate thermomechanical properties of BC2N, we investigate the effect of pressure on its high thermal conductivity and show that its thermal expansion matches that of Si, making it a good candidate as a heat sink for electronic devices.
Abnormal bandgap enlargement resulted in a promising mid-infrared nonlinear optical material Rb2CdBrI3with an ultrahigh laser damage threshold
Authors: Wu Qi , Liu Xian , Du Yeshuang , Teng Chunlin , Liang Fei
Published: May 2020

An abnormal bandgap enlargement resulted in the Rb2CdBrI3material as a good candidate for mid-infrared nonlinear optical crystal materials.
Computational design of two-photon active organic molecules for infrared responsive materials
Authors: Zaleśny Robert , Alam Md. Mehboob , Day Paul N. , Nguyen Kiet A. , Pachter Ruth , Lim Chang-Keun , Prasad Paras N. , Ågren Hans
Published: May 2020

Aiming at proposing design rules, the mechanism of two-photon absorption is analyzed in a series of π-conjugated organic cations and their neutral precursors exhibiting aggregation-enhanced optical properties.
A highly fluorescent covalent organic framework as a hydrogen chloride sensor: roles of Schiff base bonding and π-stacking
Authors: EL-Mahdy Ahmed F. M. , Lai Ming-Yi , Kuo Shiao-Wei
Published: May 2020

In this paper we report the extremely crystalline structures, high thermal stabilities, and strong fluorescence emissions of covalent organic frameworks based on linked carbazole units.
WITHDRAWN: Long intergenic non-coding RNA LINC00662 contributes to malignant growth of colorectal cancer cells by upregulating c-myc via sponging microRNA-145
Authors: Yao Zhifeng , Xu Danghui , Li Zhanfeng , Yao Jianxin , Pan Zhiyao , Chen Jinfei
Published: May 2020

The Accepted Manuscript version of this article (published on 29 May 2020) was withdrawn on 29 July 2020 at the request of the authors due to concerns over data validity.
Non‐destructive detection of coconut quality using RF sensor
Authors: Kumar Varshney A. , Pathak N.P. , Sircar D.
Published: May 2020

This Letter proposes the application of RF technology for the non‐destructive detection of spoiled coconut at the pre‐processing stage. Since the dielectric property of coconut water changes at different stages of coconut, the sensor measures the content of water inside a coconut sample non‐destructively at 2.45 GHz. The sensor has been trained to determine the threshold water level between healthy and spoiled coconut which in turn can be used to sort the coconuts. The measurement results have been presented for different processing stages of coconut for different samples. Detecting coconut quality through dielectric sensing reveals some very impressive results and opens the doors for better consumption.
Feasibility of C3F7CN/CO2 gas mixtures in high‐voltage DC GIL: a review on recent advances
Authors: Tu Youping , Chen Geng , Wang Cong , Shao Yuming , Tong Yujing , Li Chuanyang , Ma Guoming , Shahsavarian Tohid
Published: May 2020

With the rise of renewable energy resources, especially offshore wind power plant, the DC transmission concept has attracted more and more attention. The selection of eco‐friendly insulating gas, as most critical insulating part of gas‐insulated equipment is top priority for developing highly reliable system. Moreover, it is acknowledged that eco‐friendly C3F7CN/CO2 gas mixtures have become a potential alternative to SF6 gas due to its excellent performance. This study reviews the basic physical properties of C3F7CN gas/gas mixtures and insulation properties including the gas gap breakdown and surface flashover performance at DC, as well as lightning impulse voltage. Investigation about the gas stability is presented, including the compatibility of gas with solid materials in gas‐insulated transmission line (GIL), and the decomposition characteristics under long‐term electrical and thermal stresses. The important progress on the charge accumulation characteristics of gas–solid interface in the novel gas environment under DC voltage stress is analysed. Finally, the key issues that need to be paid attention to and further followed through regarding the application of this novel gas in GIL are summarised and put forward. This study hopefully can provide a complete reference for the development of eco‐friendly DC gas insulation equipment with C3F7CN/CO2 gas mixtures.
Iron loss prediction in high‐speed permanent‐magnet machines using loss model with variable coefficients
Authors: Chen Shibo , Wang Kai , Sun Haiyang
Published: May 2020

Iron loss prediction is extremely crucial to performance and thermal analysis for high‐speed permanent‐magnet (PM) machines, but it is difficult to conduct at arbitrary frequency especially high frequency. Due to the frequency‐dependent coefficients of iron loss model, although iron loss can be calculated by loss model with constant coefficients under fixed frequencies, it is not feasible to measure the required loss data of non‐oriented electrical steel under each frequency. Moreover, toroid tester is better to obtain accurate loss data of steel, but the data under specific high frequency cannot be directly measured due to the limitation of equipment and tester. Thus, this study presents a three‐term iron loss model with variable coefficients to predict iron loss of machines at arbitrary frequency, especially high frequency based on measured loss data of steel at low frequency. Although both proposed three‐term model and conventional two‐term model with variable coefficients can predict iron loss of machines at an arbitrary frequency, the comparison shows that the accuracy of the three‐term model is higher. In addition, experiments validate that proposed three‐term model with variable coefficients is accurate and feasible for iron loss prediction in high‐speed PM machines.
Data quality aware chance‐constrained DC‐OPF: a variational Bayesian Gaussian mixture approach
Authors: Wu Xiong , Wang Xiuli , Duan Chao , Dang Can , Yao Li , Fan Yue , Song Rui
Published: May 2020

The contamination of outliers severely damages the data quality, resulting in the inaccurate data‐driven optimisation model. This study proposes a data quality aware chance‐constrained model for the direct current optimal power flow (DC‐OPF) problem under uncertainties. Under the framework of Bayesian statistics, the variational Bayesian Gaussian mixture model (VBGMM) is employed to extract the probabilistic information from the available historical data, i.e. realisations of random variables. VBGMM can identify the outliers by capturing their probability characteristics, in which way improving the data quality. Notably, VBGMM automatically determines the number of components, which is a remarkable difference from the conventional Gaussian mixture model. In addition, based on the affine policy, a method integrating VBGMM with chance‐constrained programming is proposed to make VBGMM scalable. The proposed method is firstly tested on a 6‐bus system for an illustrative purpose, and then on a 118‐bus system for validating the potential practical application. Comparative studies verify the effectiveness of the proposed method.
Transient stability of power systems with embedded VSC‐HVDC links: stability margins analysis and control
Authors: Gonzalez‐Torres Juan Carlos , Damm Gilney , Costan Valentin , Benchaib Abdelkrim , Lamnabhi‐Lagarrigue Françoise
Published: May 2020

This study investigates the impact of embedded voltage source converter‐based high voltage direct current (VSC‐HVDC) links on AC grids transient stability. Firstly, using transient energy functions, it is demonstrated that VSC‐HVDC links controlled to track constant power references, do not inherently improve transient stability of the surrounding AC grid as an AC line naturally does. Then, a control law using the feedback linearisation technique on a simple but representative power system is derived. The control law highlights and combines the three main actions the VSC‐HVDC link can offer to enhance rotor angle stability: fast power reallocation, injection of synchronising power and injection of damping power. The control law is implemented and validated in EMT simulation. It is then shown that an HVDC link can assure the synchronisation of different AC areas even if no AC transmission lines interconnect them. Through another case study, it is shown how the HVDC link can help to share dynamic frequency reserves to not jeopardise the stability of the system. The last example investigates the effect of a DC fault on AC transient stability and how the control can help improving the system response.
Hybrid voltage stability and security assessment using synchrophasors with consideration of generator Q‐limits
Authors: Hur Rizvi Syed Muhammad , Kundu Pratim , Srivastava Anurag K.
Published: May 2020

Increased power demands, push for economics and limited investment in grid infrastructure have led utilities to operate power systems closer to their stability limits. Voltage instability may trigger cascade tripping, wide‐area voltage collapse, and power blackouts. Real‐time voltage stability monitoring possible with deployment of phasor measurement units (PMUs) is essential to take proactive control actions and minimise the impact on the system. This study presents a novel online algorithm for (a) hybrid perturbation analysis based voltage stability monitoring (HPVSM), (b) including Q‐limit in voltage stability index, and (c) real‐time security analysis using voltage stability index. HPVSM‐based voltage stability index is computed using the data obtained from linear state estimator and PMU measurements. Typically measurement‐based schemes ignore the impact of generator Q‐limits and security analysis is not feasible. The proposed HPVSM‐based index considers the impact of generator Q‐limits violations by anticipating the critical generators using real‐time PMU measurements. Contingencies are ranked using the proposed voltage stability index for security analysis. Results simulated for the 9‐bus WECC, IEEE 14, 57, and 118 bus systems highlight the superiority of the proposed method in real‐time voltage stability and security analysis.
Light‐weight wideband spiral antenna with a two‐layer circular HIS reflector: TL‐CirHISR spiral antenna
Authors: Tanabe Masahiro , Nakano Hisamatsu
Published: May 2020

This study describes a light‐weight wideband spiral antenna that radiates a unidirectional beam. To realise a light‐weight antenna, a one‐layer thick high‐impedance surface reflector (HISR) for a reference spiral antenna is replaced by a two‐layer circular HISR (TL‐CirHISR). The TL‐CirHISR is made of fan‐shaped patches printed on a dielectric substrate. It is revealed that a voltage standing wave ratio (VSWR) of <2 and an axial ratio of <3 dB are obtained across a design frequency range of 3.2–10 GHz (a fractional bandwidth of ∼103%). A weight reduction of 50%, compared to the weight of the reference spiral antenna, is achieved. A prototype spiral antenna with the TL‐CirHISR is fabricated and measured to confirm the analysed antenna characteristics, with good agreement between analysed and measured results obtained.
System development and experimental validation of a long‐range VNA‐based channel sounder
Authors: Mbugua Allan Wainaina , Fan Wei , Cai Xuesong , Chen Yun , Wang Wei , Olesen Kim , Pedersen Gert Frølund
Published: May 2020

In a wireless communication system, the radio propagation channel is a complicated component to characterise. Channel sounding equipment thus has to meet specific criteria to extract the desired channel parameters. In this study, the authors outline the development and validation of a vector network analyser (VNA) based channel sounder for the frequency range from 1 to 50 GHz using radio‐over‐fibre techniques. Three methods of de‐embedding phase errors due to hardware impairments are demonstrated and validated via back‐to‐back measurements. The bidirectional scheme utilising optical circulators is shown to have a superior performance over the two‐branch unidirectional and the two‐branch bidirectional schemes. Therefore, the bidirectional scheme utilising optical circulators is proposed to achieve a long‐range ultra‐channel sounder based on the VNA.
Measurement‐based determination of parameters for non‐stationary TDL models with reduced number of taps
Authors: Hassan Nina , Käske Martin , Schneider Christian , Sommerkorn Gerd , Thomä Reiner , Matolak David
Published: May 2020

This study proposes a new strategy of extracting parameters for tapped delay line (TDL) channel models from vehicle to infrastructure channel measurements. The proposed approach is based on an already existing method to derive parameters for a non‐stationary model using first‐order Markov chains. It will be shown that with the proposed method, the number of taps necessary to regenerate the delay spread of a channel can be significantly reduced. An approach will be discussed to evaluate the performance of the model. The feasibility of the method will be confirmed using channel sounding measurements.
Theoretical and experimental verification of a fast two‐dimensional Gaussian beam mode analysis method
Authors: Chen Tianyang , Chen Xiaodong , Yao Yuan , Liu Xiaoming , Yu Junsheng
Published: May 2020

In quasi‐optical systems, the beam distortion and the cross‐polarisation caused by the offset reflectors get a lot of attention. Also, the distortion was thoroughly studied in previous works. In this study, the authors give the detailed derivations of exact and approximate expressions of cross‐polarisation and some simple explanations about energy conversion between co‐ and cross‐polarisations in two‐dimensional multi‐reflector systems based on Gaussian beam mode analysis (GBMA). In addition two dual‐reflector systems with different structures are used to verify the correctness and accuracy of GBMA comparing with physical optics (PO) in commercial software GRASP10. Furthermore, the authors fabricate one of these two systems and give experimental results. Then, they propose a fast analysis algorithm based on the vector addition method to reduce the computation time by eliminating the redundant modes. The efficiency of the proposed fast algorithm is illustrated by the number of modes and the calculation time for each reflection in a tri‐reflector system. In addition, the authors also present the computation time of PO in GRASP10 as a reference. With the application of the fast algorithm, the computational efficiency is improved and increases with the number of reflections.
Wideband bandstop filters based on wideband 180° phase shifters
Authors: Qiu Lei‐Lei , Zhu Lei
Published: May 2020

In this study, a class of wideband bandstop filters is proposed based on wideband 180° phase shifters. Different from traditional signal–interference‐based bandstop filters, they make use of a 180° phase shifting in a wide operating band in principle. After numerical analysis of the phase responses of the two coupling‐line paths, the optimal solutions for the largest 180° phase‐shifting bandwidth or minimum impedance ratio can be obtained. Then, the wideband bandstop filter based on these two unique coupling lines is intensively analysed to reveal that three transmission zeros are generated in the stopband as the two paths have a 180° phase difference, thus exhibiting its wideband property. Moreover, by enlarging the impedance of the two paths, good out‐of‐band characteristics of the bandstop filter can be attained, while in‐band performances are almost unchanged. Next, two types of bandstop filters with extended bandwidth are proposed by cascading an extra delay line for both paths, and they hold similar filtering characteristics as the aforementioned one. Finally, the design process and demonstration are provided. The measured results of the three fabricated filters show that Type‐I, Type‐II, and Type‐III filters can satisfactorily obtain a 3 dB bandwidth of 108, 122, and 130% with 25, 14.7, and 11.6 dB rejection level, respectively.
Combining PRF staggering with phase‐coded inter‐pulse overlay to combat delay–Doppler ambiguities
Authors: Levanon Nadav
Published: May 2020

Pulse repetition frequency (PRF) staggering is a well‐established technique in the pulse‐Doppler radar, used in order to increase the unambiguous range and Doppler and to minimise blind spots. The study offers a new staggering dimension that can increase the number of different staggering choices. The new approach is to add an inter‐pulse coherent phase‐coded overlay. The code is shorter than the number of pulses in each PRF batch and is repeated an integer number of times within the batch. A required property of the phase code is perfect periodic autocorrelation, namely zero autocorrelation sidelobes. In order to minimise the added complexity, the overlay codes use a two‐phase or three‐phase alphabet. As in a conventional PRF staggering, there are P coherent batches, each using a different PRF, with its matched phase‐coded overlay. The performance analysis uses a conventional binary integration rule that declares detection if there were H, or more, individual detections in the P batches.
Stochastic modelling of electric vehicle behaviour to estimate available energy storage in parking lots
Authors: Bin Irshad Usama , Rafique Sohaib , Town Graham
Published: May 2020

The increasing penetration of electric vehicles (EVs) brings challenges and opportunities for power systems. One particular opportunity concerns the use of parked EVs to provide energy and associated services to the grid. In this work, the potential energy storage capacity of parking lots (PLs) of EVs is computed using the proposed stochastic model which considers the sporadic nature of the EV’ behaviours (i.e. arrival/departure, battery degradation, travel pattern, charge/discharge rates). The analysis was performed for two types of PLs with very different occupancy distributions, i.e. a shopping centre PL, and a workplace PL. In both cases, the available energy storage capacity of EVs was estimated hourly using real household travel data, i‐MiEV data and car park occupancy records. The results show that the aggregated energy storage capacity closely follows the occupancy of EVs in the PLs, and is substantial, with little sensitivity to charging rate. The proposed stochastic modelling considered the variations in energy consumption, battery degradation, and user behaviour, predicted 13.4% less peak capacity than deterministic modelling. Moreover, the authors conclude that the shopping centre PL is a viable energy resource to the grid, with their scale and throughput compensating for the relatively low occupancy.