bluuebunny/crossref_metadata_2025 huggingface dataset:
Metacommunity robustness of plant–fly–wasp tripartite networks with specialization to habitat loss
Authors: Liao Jinbao , Xi Xinqiang , Bearup Daniel , Sun Shucun
Published: April 2020

Recent observations have found plant‐species‐specific fly‐host selection (i.e., specialization) of wasp parasitoids (wasps) in plant–fly–wasp (P–F–W) tripartite networks, yet no study has explored the dynamical implications of such high‐order specialization for the persistence of this network. Here we develop a patch‐dynamic framework for a unique P–F–W tripartite network with specialization observed in eastern Tibetan Plateau and explore its metacommunity robustness to habitat loss. We show that specialization in parasitoidism promotes fly species diversity, while the richness of both plant and wasp decreases. Compared to other two null models, real network structure favors plant species coexistence but increases the extinction risk for both flies and wasps. However, these effects of specialization and network structure would be weakened and ultimately disappear with increasing habitat loss. Interestingly, intermediate levels of habitat loss can maximize the diversity of flies and wasps, while increasing or decreasing habitat loss results in more species losses, supporting intermediate disturbance hypothesis. Finally, we observe that high levels of habitat loss initiate a bottom‐up cascade of species extinction from plants to both flies and wasps, resulting in a rapid collapse of the whole tripartite networks. Overall, this theoretical framework is the first attempt to characterize the dynamics of whole tripartite metacommunities interacting in realistic high‐order ways, offering new insights into complex multipartite networks.
Monozygotic twins with myocarditis and a novel likely pathogenic desmoplakin gene variant
Authors: Kissopoulou Antheia , Fernlund Eva , Holmgren Christina , Isaksson Eira , Karlsson Jan‐Erik , Green Henrik , Jonasson Jon , Ellegård Rada , Årstrand Hanna Klang , Svensson Anneli , Gunnarsson Cecilia
Published: April 2020

Myocarditis most often affects otherwise healthy athletes and is one of the leading causes of sudden death in children and young adults. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically determined heart muscle disorder with increased risk for paroxysmal ventricular arrhythmias and sudden cardiac death. The clinical picture of myocarditis and ARVC may overlap during the early stages of cardiomyopathy, which may lead to misdiagnosis. In the literature, we found several cases that presented with episodes of myocarditis and ended up with a diagnosis of arrhythmogenic cardiomyopathy, mostly of the left predominant type. The aim of this case presentation is to shed light upon a possible link between myocarditis, a desmoplakin (DSP) gene variant, and ARVC by describing a case of male monozygotic twins who presented with symptoms and signs of myocarditis at 17 and 18 years of age, respectively. One of them also had a recurrent episode of myocarditis. The twins and their family were extensively examined including electrocardiograms (ECG), biochemistry, multimodal cardiac imaging, myocardial biopsy, genetic analysis, repeated cardiac magnetic resonance (CMR) and echocardiography over time. Both twins presented with chest pain, ECG with slight ST‐T elevation, and increased troponin T levels. CMR demonstrated an affected left ventricle with comprehensive inflammatory, subepicardial changes consistent with myocarditis. The right ventricle did not appear to have any abnormalities. Genotype analysis revealed a nonsense heterozygous variant in the desmoplakin (DSP) gene [NM_004415.2:c.2521_2522del (p.Gln841Aspfs*9)] that is considered likely pathogenic and presumably ARVC related. There was no previous family history of heart disease. There might be a common pathophysiology of ARVC, associated with desmosomal dysfunction, and myocarditis. In our case, both twins have an affected left ventricle without any right ventricular involvement, and they are carriers of a novel DSP variant that is likely associated with ARVC. The extensive inflammation of the LV that was apparent in the CMR may or may not be the primary event of ARVC. Nevertheless, our data suggest that irrespective of a possible link here to ARVC, genetic testing for arrhythmogenic cardiomyopathy might be advisable for patients with recurrent myocarditis associated with a family history of myocarditis.
Hexacyanoferrate‐Intercalated Layered Double Hydroxides as Nanoadditives for the Detection of Early‐Stage Corrosion of Steel: The Revival of Prussian blue
Authors: Wilhelm Manon , Quevedo Marcela C. , Sushkova Alesia , Galvão Tiago L. P. , Bastos Alexandre , Ferreira Mário , Tedim João
Published: April 2020

This work describes the synthesis and characterization of Zn‐Al and Mg‐Al layered double hydroxides (LDHs) intercalated with hexacyanoferrate. X‐ray diffraction, infrared spectroscopy and scanning electron microscopy indicated a successful intercalation of hexacyanoferrate in the sub‐micrometer sized platelet‐like particles. Release studies of hexacyanoferrate from LDHs found that the anion is released depending on the concentration of NaCl and under alkaline conditions. When placed in contact with carbon steel under corrosive conditions, the formation of Prussian blue was detected. Furthermore, the application of potentiodynamic polarization and electrochemical impedance spectroscopy revealed that hexacyanoferrate has a detrimental effect on the corrosion of carbon steel, while when intercalated in LDHs this effect is minimized. Overall, these findings open perspectives for the application of these materials as smart nanoadditives in coatings for corrosion detection.
Electrochemical Sensing of Chemical Warfare Agent Based on Hybrid Material Silver‐aminosilane Graphene Oxide
Authors: Singh Virendra V. , Sharma Pushpendra K. , Shrivastava Anchal , Gutch Pranav K. , Ganesan Kumaran , Boopathi Mannan
Published: April 2020

The threat from chemical warfare agents (CWAs) imparts an alarming call for the global community not limited to human being but also extends as unprecedented environmental threat, hence, timely detection and degradation in the event of CWAs attack is very crucial. Herein, we describe a hybrid material of 3‐aminopropyltriethoxysilane (APTES) modified graphene oxide (GO) on glassy carbon (GC) electrode along with electrodeposited silver nanodendrimers (AgNDs) for the electrochemical detection and degradation of CWA sulphur mustard (HD). The AgNDs/APTES‐GO hybrid material was characterized by SEM, EDX, BET, TGA, Raman, UV‐Vis, XPS and XRD techniques. The AgNDs/APTES‐GO modified GC electrode was also characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Electrochemical studies indicated presence of electrocatalysis owing to the synergistic effect of AgNDs and GO for sensing CWA HD via reductive dehalogenation. The AgNDs/APTES‐GO modified GC electrode exhibited linearity for CWA HD from 5.3 μM to 42.4 μM. Constant potential electrolysis was performed with modified electrode and degradation products were analysed using GC‐MS, highlighting the great potential of graphene based hybrid material. This new strategy provides an opportunity for the development of “detect and destroy” system for the CWAs and other environmental toxic pollutant, which could help in mitigation of on‐ site events for first responders.
An In‐Plane Sliding Triboelectric Nanogenerator with a Multielectrode Array for Self‐Powered Dynamic Addressing and Trajectory Tracking
Authors: Yang Shuai , Zhang Hulin , Sang Shengbo
Published: April 2020

The recognition and detection of micromotion, widely existant in modern microsystems, directly affects the sensing performance of advanced low‐dimensional electronics. Herein, a subtle in‐plane sliding triboelectric nanogenerator (TENG) composed of a polytetrafluoroethylene (PTFE) plate and an adjustable Al electrode array is reported. Each TENG unit can deliver an open‐circuit voltage of about 11.6 V, with a short‐circuit current close to 36 nA. An array of Al electrodes linearly aligned along the sliding direction enables dynamic addressing by recording and calculating sliding time without interference from sliding speed. In addition, two types of TENG‐based flexible self‐powered sensor matrices show an accurate mapping capability for stylus or finger movements, realizing real‐time trajectory tracking without using any external power sources. Herein, TENG‐based sensing applications are expanded, especially in active artificial intelligence and Internet of things.
Multi‐criteria decision making for seismic intensity measure selection considering uncertainty
Authors: Qian Jing , Dong You
Published: April 2020

Seismic intensity measure (IM) selection is associated with consideration of multiple criteria, and there are uncertainties within the selection process. In this paper, a novel multi‐criteria decision making (MCDM) approach by incorporating stochastic multi‐criteria acceptability analysis (SMAA) with technique for order preference by similarity to ideal solution (TOPSIS) is proposed to solve the stochastic decision making problem of IM selection. TOPSIS provides an alternative rank function, and the SMAA is used to address the uncertainties within the IM selection. The performance criteria (e.g., efficiency, proficiency, practicality, sufficiency, and correlation) are evaluated for the investigated structural components, and the decision matrix is formulated based on the criteria of each IM alternative. Furthermore, the importance of the component to system reliability is quantified in a probabilistic manner using nonlinear time history analysis and serves as the weighting factors in MCDM stage. The holistic acceptability indices indicating the overall acceptability levels of IM alternatives are computed by the proposed approach. Additionally, the effects of different IMs (e.g., average spectral acceleration, peak ground velocity, and spectral acceleration) on probabilistic seismic loss and resilience are investigated to further support the IM selection. The proposed approach is illustrated on a highway bridge, and the results are presented.
Isotopic (Sr, Nd, and Os) compositions of Zhaxikang diabases, southern Tibet: Records of mantle‐plume activity and implications for Zhaxikang Sb–Pb–Zn–Ag mineralization
Authors: Li Ruyue , Sun Xiang , Mou Nini , Li Chao , Wan Xiuquan , Yu Miao
Published: April 2020

Diabases from the Zhaxikang Sb–Pb–Zn–Ag deposit in southeastern Tibet provide an opportunity to reveal the tempo‐spatial distribution of the recently identified Comei large igneous province and understand the association with Zhaxikang mineralization. Here we present whole‐rock geochemical and Sr–Nd–Re–Os isotopic data on the Zhaxikang diabases. The Zhaxikang diabases have a Re–Os isochron age of 136.1 ± 3.1 Ma. These rocks are characterized by high TiO2 content (3.0–4.2 wt%) and have alkaline ocean island basalt‐like trace element patterns with initial 87Sr/86Sr ratios of 0.7060–0.7069, εNd(t) values of 1.3–3.3, and 187Os/188Os(t) ratios of 0.12–0.13. The Zhaxikang diabases are part of the Comei large igneous province and were derived from partial melting of enriched garnet‐bearing mantle source and related to interaction of plume melts with subcontinental lithospheric mantle. Our new data provided additional evidence that Zhaxikang Pb–Zn(Ag)‐bearing Mn–Fe carbonate veins were not produced by a sedimentary exhalative event in Triassic–Jurassic rift environment.
Influence and analysis of structure design and optimization on the performance of a pit drip irrigation emitter*
Authors: Xu Tianyu , Zhang Lixiang
Published: April 2020

This study aimed at enhancing the performance of an emitter by optimizing the flow channel and reducing the flow index, which improves the energy dissipation coefficient and anti‐clogging ability of a pit drip irrigation emitter (PDIE). Methodologies of a flow numerical simulation and a model experiment were used to evaluate the influence of four types of optimized structure schemes of PDIE. The results show that the low‐velocity vortex zone in the flow channel increased the energy dissipation coefficient, and decreased the flow index, in which anti‐clogging ability was decreasing. The optimal design schemes 3 and 4 had a good working performance by reducing the flow area at the upper and lower ends of the PDIE and adding the resistance of the torus edge; the former added two triangles and the latter an arc and a triangle. The flow index was between 0.482 and 0.486, and the energy dissipation coefficient was 843–912. The optimizations improved the anti‐clogging ability by increasing the flow resistance and reducing the low‐velocity vortex zone. The experimental error compared with the numerical simulation for the flow index and the energy dissipation coefficient was less than 3%. This indicated that the analytical method used in this study was reliable. © 2020 John Wiley & Sons, Ltd.
Constructions of pairs of orthogonal latin cubes
Authors: Potapov Vladimir N.
Published: April 2020

A pair of orthogonal latin cubes of order is equivalent to a maximum distance separable code with distance 3 or to an orthogonal array. We construct pairs of orthogonal latin cubes for sequences of previously unknown orders and . The minimal new obtained parameters of orthogonal arrays are .
Photocatalytic reforming of glycerol to H2 in a thin film Pt‐TiO2 recirculating photoreactor
Authors: Skillen Nathan , Ralphs Kathryn , Craig David , McCalmont Sam , Muzio Aline F V , O'Rourke Christopher , Manyar Haresh , Robertson Peter K J
Published: April 2020

BACKGROUND

With an increase in global bioenergy production, the ‘biorefinery concept’ has now become a significant focus of research. The desire to achieve efficient conversion of biomass material into both energy and value‐added products requires a combination of technologies and processes. As such, the photocatalytic reforming of feedstocks such as glycerol to hydrogen (H2) has a lot of potential.

RESULTS

Reported here is the first example of a thin film‐based photocatalytic system capable of achieving H2 evolution using a glycerol feedstock. Using a titania (TiO2) sol–gel, glass columns were coated with a thin TiO2 layer before using photodeposition to add platinum (Pt) as a co‐catalyst. The coated columns were assembled into a simple yet effective recirculating system which used low power UV irradiation. Under optimum conditions (two coated columns and a 40 mL min−1 flow rate), a steady state of 0.9 μmol min−1 H2 with a photonic efficiency [ηphoton (%)] of 10.22 % was achieved. Furthermore, only one column showed flaking and loss of coating whereas the remaining columns were stable for the duration of the study, which equated to > 100 h of experimental testing including replicates and determining optimal parameters.

CONCLUSION

H2 evolution via photocatalytic glycerol reforming in a Pt‐TiO2 thin film catalyst recirculating system has been demonstrated under UV irradiation and ambient conditions. The system developed highlights that it is both catalyst development and reactor engineering that are required to continue to advance the field of photocatalysis. © 2020 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
First‐trimester treatment of cesarean scar pregnancy using a cervical ripening—double‐balloon catheter: A case report
Authors: Spazzini Maria Donata , Villa Antonella , Maffioletti Cristina , Mariuzzo Federica , Calì Giuseppe
Published: April 2020

Cesarean scar pregnancies are relatively rare. In the first trimester, if the decision is made to terminate the pregnancy, it should be done as soon as possible to avoid complications. We report a successful termination of a live, 6 weeks and 4 days cesarean scar pregnancy using a double‐balloon cervical ripening catheter in a patient with two previous cesarean deliveries.
A characterization of nonfeasible sets in matching covered graphs
Authors: Liu Qinghai , Cui Qing , Feng Xing , Lu Fuliang
Published: April 2020

Let be a matching covered graph and let . Then is called feasible if there exist two perfect matchings and in such that ; otherwise, it is nonfeasible. For any vertex , the switching operation of in is defined as the symmetric difference of and , where denotes the set of all edges in incident with . Two sets are switching‐equivalent if can be obtained from by a series of switching operations and vice visa. Lukot'ka and Rollová showed that if is a regular bipartite graph, then is nonfeasible if and only if is switching‐equivalent to (as well as ). In this paper, we give a complete characterization of nonfeasible sets in matching covered graphs. We prove that if is a matching covered graph and is an arbitrary nonfeasible set of , then is switching‐equivalent to both and if and only if is bipartite, and is switching‐equivalent to either or (but not both) if and only if is nonbipartite and has an ear decomposition with exactly one double ear. We also show that for any two integers and with and , there exist infinitely many ‐regular simple graphs of class 1 with arbitrarily large brick number, connectivity and a nonfeasible set such that is not switching‐equivalent to either or . This gives negative answers to two problems proposed by Lukot'ka and Rollová and by He et al, respectively.
Learning the developments in EMTALA jurisprudence through the lens of John West's “case law update”
Authors: Bitterman Robert A.
Published: April 2020

This article covers three recurring issues concerning the federal law known as the Emergency Medical Treatment and Labor Act (EMTALA) that keep popping up in John West's Case Law Update case updates, and consistently bedevil hospital risk managers. First, what exactly constitutes an “appropriate” medical screening examination; second, when is a patient actually “stabilized’ under EMTALA; and third, does the EMTALA obligation really “disappear” when a patient is admitted to the hospital? The editors wanted to analyze topics that challenge the courts to “get it right” on the law and that drive risk managers crazy. EMTALA is the “poster child” for such a topic.
Response of shallow soil temperature to climate change on the Qinghai–Tibetan Plateau
Authors: Wang Xiqiang , Chen Rensheng , Han Chuntan , Yang Yong , Liu Junfeng , Liu Zhangwen , Guo Shuhai , Song Yaoxuan
Published: April 2020

Under climate change, soil temperature change remarkably influences regional landscapes, ecosystems, hydrological processes, and other parameters. Based on daily soil temperature data from 56 stations from 1965 to 2014, the spatiotemporal variations in shallow soil temperature (0, 5, 10, 15, and 20 cm) on the Qinghai–Tibetan Plateau (QTP) were investigated. The mean shallow soil temperature decreased obviously with altitude both annually and seasonally, except in winter. Primarily dependent on station latitude, the spatial distribution of winter soil temperature was significantly affected by the snow cover conditions. As the soil depth increased, the soil temperature showed a cooling trend in spring and summer but a warming trend in autumn and winter. In the past 50 years, the shallow soil temperature increased considerably on the QTP both annually and seasonally. The warming rate of soil temperature was greatly dependent on station altitude in winter and dependent on latitude in summer and longitude in autumn. Unlike the increasing air temperature that was contributed mainly by winter, the warming rate of soil temperature in winter at depths of 5, 10, 15, and 20 cm was obviously lower than that in other seasons and air temperature in winter. This occurrence may be caused by relatively less snow cover in winter, which produces a weak insulation effect and further makes the soils more vulnerable to cooling from cold air. For the entire region, the soil temperature variability was strongly correlated with the change in air temperature but weakly correlated with precipitation. Although the warming rate in shallow soil tended to be low (high) at stations with a high amount of precipitation (snow cover), the influence of precipitation (including snow) on shallow soil temperature was limited on the QTP in the past few decades.
Structure, function, and defect tolerance with maturation of the radial tie fiber network in the knee meniscus
Authors: Bansal Sonia , Peloquin John M. , Keah Niobra M. , O'Reilly Olivia C. , Elliott Dawn M. , Mauck Robert L. , Zgonis Miltiadis H.
Published: April 2020

The knee menisci are comprised of two orthogonal collagenous networks—circumferential and radial—that combine to enable efficient load bearing by the tissue in adults. Here, we assessed how the structural and functional characteristics of these networks developed over the course of skeletal maturation and determined the role of these fiber networks in defect tolerance with tissue injury. Imaging of the radial tie fiber (RTF) collagen structure in medial bovine menisci from fetal, juvenile, and adult specimens showed increasing heterogeneity, anisotropy, thickness, and density with skeletal development. The mechanical analysis showed that the tensile modulus in the radial direction did not change with skeletal development, though the resilience (in the radial direction) increased and the tolerance to defects in the circumferential direction decreased, in adult compared to fetal tissues. This loss of defect tolerance correlated with increased order in the RTF network in adult tissue. These data provide new insights into the role of the radial fiber network in meniscus function, will lead to improved clinical decision‐making in the presence of a tear and may improve engineering efforts to reproduce this critical load‐bearing structure in the knee.
Biochemical changes of the pericellular matrix and spatial chondrocyte organization—Two highly interconnected hallmarks of osteoarthritis
Authors: Danalache Marina , Erler Anna‐Lisa , Wolfgart Julius M. , Schwitalle Maik , Hofmann Ulf K.
Published: April 2020

During osteoarthritis, chondrocytes change their spatial arrangement from single to double strings, then to small and big clusters. This change in pattern has recently been established as an image‐based biomarker for osteoarthritis. The pericellular matrix (PCM) appears to degrade together alongside cellular reorganization. The aim of this study was to characterize this PCM‐degradation based on different cellular patterns. We additionally wanted to identify the earliest time point of PCM‐breakdown in this physiopathological model. To this end, cartilage samples were selected according to their predominant cellular pattern. Qualitative analysis of PCM degradation was performed immunohistochemically by analysing five main PCM components: collagen type VI, perlecan, collagen type III, biglycan, and fibrillin‐1 (n = 6 patients). Their protein content was quantified by enzyme‐linked immunosorbent assay (127 patients). Accompanying spatial cellular rearrangement, the PCM is progressively destroyed, with a pericellular signal loss in fluorescence microscopy for collagen type VI, perlecan, and biglycan. This loss in protein signal is accompanied by a reduction in total protein content from single strings to big clusters (P < .001 for collagen type VI, P = .003 for perlecan, and P < .001 for biglycan). As a result of an increase in the number of cells from single strings to big clusters, the amount of protein available per cell also decreases for collagen type III and fibrillin‐1, where total protein levels remain constant. Biochemical changes of the PCM and cellular rearrangement are thus highly interconnected hallmarks of osteoarthritis. Interestingly, the earliest point in time for a relevant PCM impairment appears to be at the transition to small clusters.
Bioactive polymeric scaffolds for osteogenic repair and bone regenerative medicine
Authors: Amiryaghoubi Nazanin , Fathi Marziyeh , Pesyan Nader Noroozi , Samiei Mohammad , Barar Jaleh , Omidi Yadollah
Published: April 2020

The loss of bone tissue is a striking challenge in orthopedic surgery. Tissue engineering using various advanced biofunctional materials is considered a promising approach for the regeneration and substitution of impaired bone tissues. Recently, polymeric supportive scaffolds and biomaterials have been used to rationally promote the generation of new bone tissues. To restore the bone tissue in this context, biofunctional polymeric materials with significant mechanical robustness together with embedded materials can act as a supportive matrix for cellular proliferation, adhesion, and osteogenic differentiation. The osteogenic regeneration to replace defective tissues demands greater calcium deposits, high alkaline phosphatase activity, and profound upregulation of osteocalcin as a late osteogenic marker. Ideally, the bioactive polymeric scaffolds (BPSs) utilized for bone tissue engineering should impose no detrimental impacts and function as a carrier for the controlled delivery and release of the loaded molecules necessary for the bone tissue regeneration. In this review, we provide comprehensive insights into different synthetic and natural polymers used for the regeneration of bone tissue and discuss various technologies applied for the engineering of BPSs and their physicomechanical properties and biological effects.
In vitro characterization of the serotonin biosynthesis pathway by CEST MRI
Authors: Oglesby Ryan T. , Lam Wilfred W. , Stanisz Greg J.
Published: April 2020

Purpose

The diagnosis of monoamine‐related psychiatric disorders is based on the phenomenological evaluation of symptoms and behavior by trained clinicians. The CEST technique can be sensitive to monoamines such as serotonin. This study quantifies the CEST properties of the compounds in the serotonin biosynthesis pathway with the goal of developing noninvasive techniques aimed at advancing the diagnostic assessment of serotonin dysfunction.

Methods

Saturation transfer‐weighted images of L‐tryptophan, 5‐hydroxytryptophan, serotonin, 5‐hydroxyindoleacetic acid, and melatonin phantoms were acquired over a range of saturation amplitudes and frequency offsets along with observed T1, T2, and B1 efficiency maps at physiological temperature and pH of 5.5, 6.7, and 7.4. The CEST and MT data were fitted to a three‐pool Bloch–McConnell model of exchange to estimate the model parameters.

Results

At a pH of 5.5, tryptophan, 5‐hydroxytryptophan and serotonin exhibited significant CEST contrast at resonance frequency offset, Δω between 2.64 ppm and 2.71 ppm, and magnetization transfer ratio asymmetry amplitudes up to 20% per 30 mM. At a pH of 7.4, all molecules exhibited significant CEST contrast between 5.11 ppm and 5.47 ppm, and magnetization transfer ratio asymmetry amplitudes up to 9.5% per 30 mM. At a pH of 6.7, all studied compounds except melatonin exhibited a CEST peak from each of the preceding two pHs.

Conclusion

At a pH of 5.5, tryptophan, 5‐hydroxytryptophan, and serotonin CEST contrast originates from the
side chain, whereas at a pH of 7.4, CEST contrast is due to the chemical exchange between water and the NH proton on the indole ring. The data in this study could be used to inform future investigations aimed at detecting and measuring in vivo serotonin.
Accelerating GluCEST imaging using deep learning for B0 correction
Authors: Li Yiran , Xie Danfeng , Cember Abigail , Nanga Ravi Prakash Reddy , Yang Hanlu , Kumar Dushyant , Hariharan Hari , Bai Li , Detre John A. , Reddy Ravinder , Wang Ze
Published: April 2020

Purpose

Glutamate weighted Chemical Exchange Saturation Transfer (GluCEST) MRI is a noninvasive technique for mapping parenchymal glutamate in the brain. Because of the sensitivity to field (B0) inhomogeneity, the total acquisition time is prolonged due to the repeated image acquisitions at several saturation offset frequencies, which can cause practical issues such as increased sensitivity to patient motions. Because GluCEST signal is derived from the small z‐spectrum difference, it often has a low signal‐to‐noise‐ratio (SNR). We proposed a novel deep learning (DL)‐based algorithm armed with wide activation neural network blocks to address both issues.

Methods

B0 correction based on reduced saturation offset acquisitions was performed for the positive and negative sides of the z‐spectrum separately. For each side, a separate deep residual network was trained to learn the nonlinear mapping from few CEST‐weighted images acquired at different ppm values to the one at 3 ppm (where GluCEST peaks) in the same side of the z‐spectrum.

Results

All DL‐based methods outperformed the “traditional” method visually and quantitatively. The wide activation blocks‐based method showed the highest performance in terms of Structural Similarity Index (SSIM) and peak signal‐to‐noise ratio (PSNR), which were 0.84 and 25dB respectively. SNR increases in regions of interest were over 8dB.

Conclusion

We demonstrated that the new DL‐based method can reduce the entire GluCEST imaging time by ˜50% and yield higher SNR than current state‐of‐the‐art.
Imidazolium functionalized poly(vinyl alcohol) membranes for direct methanol alkaline fuel cell applications
Authors: Albayrak Arı Gülşen , Şimşek Öykü
Published: April 2020

In this study, imidazolium functionalized poly(vinyl alcohol) (PVA) was synthesized by acetalization and direct quaternization reaction. Afterwards, composite anion exchange membranes based on imidazolium‐ and quaternary ammonium‐ functionalized PVA were used for direct methanol alkaline fuel cell applications. 1H NMR and Fourier transform infrared spectroscopy data indicated that imidazole functionalized PVA was successfully synthesized. Inductively coupled plasma mass spectrometry data demonstrated that the imidazolium structure was efficiently obtained by direct quaternization of the imidazole group. Composite anion exchange membranes were fabricated by application of the functionalized PVA solution on the surface of porous polycarbonate (PC) membranes. Fuel cell related properties of all prepared membranes were investigated systematically. The imidazolium functionalized composite membrane (PVA‐Im/PC) exhibited higher ionic conductivity (7.8 mS cm−1 at 30 °C) despite a lower water uptake and ion exchange capacity value compared to that of quaternary ammonium. In addition, PVA‐Im/PC showed the lowest methanol permeation rate and the highest membrane selectivity as well as high alkaline and oxidative stability. Dynamic mechanical analysis results reveal that both composite membranes were mechanically resistant up to 107 Pa at 140 °C. The superior performance of imidazolium functionalized PVA composite membrane compared to quaternary ammonium functionalized membrane makes it a promising candidate for direct methanol alkaline fuel cell applications. © 2020 Society of Chemical Industry
Crystal Morphology of 3,4‐Bis(3‐nitrofurazan‐4‐yl)furoxan in Methanol and Acetic Acid/Water Solutions by Spiral Growth Mechanism
Authors: Song Liang , Zhao Feng‐Qi , Xu Si‐Yu , Ju Xue‐Hai , Ye Cai‐Chao
Published: April 2020

The crystal morphologies of 3,4‐bis(3‐nitrofurazan‐4‐yl)furoxan (DNTF) are diamond‐shaped in methanol as well as in acetic acid/water (7 : 3) solutions. There is a possibility that the two solutions have similar effects on the morphologies of DNTF. To explain this phenomenon, a spiral growth model in consideration of adhesion energy, temperature, solubility, and supersaturation was implemented to predict the crystal morphologies of the DNTF in the two solutions. The interface model based on the experimental situation was constructed as a periodic supercell. The molecular dynamics simulation was performed to obtain the attachment energy at the equilibrium structure. The results indicate that the (001), (111) and (11
) faces become dominantly exposed faces, while the (011), (101) and (110) faces disappear or occupy a very small area in both solutions. The prediction results are in remarkable agreement with the experimental observations in cooling crystallization. The simulation method can provide theoretical support for the crystallization process of DNTF.
Relative bioavailability and pharmacokinetic comparison of calcium glucoheptonate with calcium carbonate
Authors: Wiria MSS , Tran Hung Manh , Nguyen Phuc H. B. , Valencia Olivia , Dutta Surajit , Pouteau Etienne
Published: April 2020

Adequate calcium intake is important for the prevention of bone loss and osteoporosis. For some populations such as those of Southeast Asia where calcium intake is very low, supplements represent a suitable dietary source of calcium. The objective of this study was to compare the relative oral bioavailability of calcium from calcium glucoheptonate, a highly soluble calcium salt containing 8.2% of elemental calcium, to that of calcium carbonate. A single‐dose, randomized‐sequence, open‐label, two‐period crossover study, with a 7‐day washout period, was conducted in 24 Indonesian healthy adult volunteers. After a 12‐hour (overnight) fast, subjects received either two oral ampoules of 250 mg/10 mL of calcium glucoheptonate each or one effervescent tablet of calcium carbonate containing 500 mg of elemental calcium. The relative oral bioavailability of calcium from calcium glucoheptonate as compared to calcium carbonate was 92% within 6 hours and 89% within 12 hours after study drug administration. The 90% confidence intervals for the mean test/reference ratios of the maximum plasma concentration and the area under the concentration‐time curve at 12 hours post‐administration were 77.09%–120.31% and 60.58%–122.30%, respectively. Five subjects experienced a total of eight adverse events which were all mild and transient; no serious adverse events or deaths were reported. These results indicate that calcium glucoheptonate is associated with a high relative bioavailability of calcium compared to calcium carbonate, and is well‐tolerated. Calcium glucoheptonate might thus be a potential choice for calcium supplementation in Southeast Asian populations.
Role of Hot Electrons in the Development of GaAs‐Based Spin Hall Devices with Low Power Consumption
Authors: Mudi Priyabrata , Khamari Shailesh K. , Sharma Tarun K.
Published: April 2020

Strong inverse spin Hall effect (ISHE) signal can be realized in GaAs via the electrical injection of hot electrons. In a recent article, it was demonstrated that optically induced hot electrons can also lead to the establishment of ISHE in GaAs but at much lower electric field. Herein, the combined role of high electric field and high energy optical injection of hot electrons in GaAs is examined. An anomalous behavior of ISHE voltage (VISHE) is observed. Spin‐polarized hot‐electrons are optically injected in the conduction band of n‐GaAs which are then transferred from Γ to L valley with or without applied bias. At 2.33 eV excitation energy (Eex), a monotonous increase in VISHE is seen with electric field which starts to fall beyond a critical electric field. A theoretical framework based on the rate equations governing intervalley scattering is proposed, which successfully explains the observed behavior. Utilizing optically injected hot electrons at Eex = 2.33 eV, a spin Hall device is demonstrated, that consumes less power and yields better signal‐to‐noise ratio. These findings are highly encouraging for the development of next‐generation spin‐optoelectronic devices.
Position of Disulfide Bond Determines the Properties of Novel Stimuli‐Responsive Cationic Lipids
Authors: Puchkov Pavel A. , Shmendel Elena V. , Luneva Anastasia S. , Zenkova Marina A. , Maslov Michael A.
Published: April 2020

Effective release of nucleic acids from the lipoplexes to the cytoplasm is one of the challenges of gene delivery systems. Stimuli‐responsive groups such as disulfide linkages offer an attractive solution. We designed two novel polycationic amphiphiles with disulfide links (2S3 and 2S4) and compared their transfection efficiency with their nonredox‐sensitive analogue 2X3. The stability and redox sensitivity of lipoplexes formed by cationic liposomes 2X3, 2S3, and 2S4 with plasmid DNA were studied using different destabilizing agents, such as glutathione, 1,4‐dithiothreitol, and heparin using electrophoresis and fluorescent titration assays. Further, we performed size and ζ‐potential analysis of cationic liposomes and lipoplexes, and also compared their transfection efficiencies in the presence of the destabilizing agents. Depending on their structure, disulfide lipoplexes exhibited different sensitivity towards the destabilizing agents. Moreover, high redox‐sensitivity correlated well with higher transfection activity into HEK293 cells.
CuII‐Tyrosinase Enzyme Catalyst‐Mediated Synthesis of 2‐Thioxopyrimidine Derivatives with Potential Mosquito Larvicidal Activity: Spectroscopic and Computational Investigation as well as Molecular Docking Interaction with OBPs of Culex quinquefasciatus
Authors: SathishKumar Chidambaram , Keerthana Selvaraj , Ahamed Anis , Arif Ibrahim A. , SurendraKumar Radhakrishnan , Idhayadhulla Akbar
Published: April 2020

A series of 2‐thioxo pyrimidine derivatives 1, (1 a‐1 e) and 2, (2 a‐2 e) were synthesized via Biginelli reaction by using CuII‐tyrosinase (CuII‐Tyr) as an enzyme catalyst in up to 80–92% yield. The compounds 1, (1 a‐1 e) and 2, (2 a‐2 e) were characterized by IR, 1H NMR, 13C NMR, mass spectra and elemental analyses. The synthesized compounds 1, (1 a‐1 e) and 2, (2 a‐2 e) were screened for mosquito larvicidal activity against Culex quinquefasciatus. The compound 2 a was 80% mortality at 100 μg/mL with the LD50 value of 55.94 μg/mL than the control Permethrin 60.03 μg/mL respectively. Molecular docking studies of synthesized compounds were carried out and the results proposed that the compound 2 a as a potential candidate to mosquito odorant‐binding protein 3OGN inhibitors. In addition, computational studies, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies showed that the charge transfer occurs in the inside of the molecule and also gives the chemical reactivity descriptors, and molecular electrostatic potential (MESP) is also calculated. Therefore, experimental and theoretical studies were well supported for the compound 2 a as a potential larvicide activity aganist mosquito larvae of Culex quinquefasciatus.
Synthesis, Characterization, Photophysical and Photochemical Properties of Novel Phthalocyanines
Authors: Demirbaş Ümit
Published: April 2020

The benzothiazole substituted phthalonitrile (3) and non‐peripherally tetra benzothiazole substituted metal‐free (4), zinc(II) (5) and lead(II) phthalocyanine (6) complexes were prepared. The compounds (3‐6) were characterized by IR, NMR, UV‐Vis and mass spectroscopy data. After synthesis, photochemical and photophysical parameters of the compounds (4‐6) were analyzed to determine photosensitizer performance of them for PDT applications. Firstly, the most suitable solvent for compounds (4‐6) was found by aggregation studies. Then, fluorescence properties were measured in DMF at 1x10−6 M. Singlet oxygen properties were measured in DMF by using 1,3‐diphenylisobenzofuran (DPBF) as a singlet oxygen quencher. Photodegradation properties were measured under light irradiation in DMF at 1x10−5 M. The zinc(II) phthalocyanine (5) had the highest singlet oxygen production capacity (Φ▵=0.62), fluorescence (ΦF=0.25) and photodegradation quantum yield (Φd=3.28x10‐4). The results showed that zinc(II) phthalocyanine (5) has potential for photodynamic therapy applications.
Electrosynthesis of Poly(aniline‐co‐pyrrole‐co‐N‐methylpyrrole) Terpolymer and Poly(aniline‐co‐pyrrole‐co‐N‐methylpyrrole)‐TiO2 Nanocomposite on Steel
Authors: Akdag Abdurrahman
Published: April 2020

Poly(aniline‐co‐pyrrole‐co‐N‐methylpyrrole) (P(ANI‐co‐PY‐co‐NMP)) terpolymer film was synthesized in 0.30 M oxalic acid solutions containing 0.05 M aniline +0.05 M pyrrole +0.05 M N‐methylpyrrole. Poly(aniline‐co‐pyrrole‐co‐N‐methylpyrrole)‐TiO2 nanocomposites were synthesized in 0.30 M oxalic acid solutions containing 0.05 M aniline +0.05 M pyrrole+0.05 M N‐methylpyrrole+0.1/0.4/1.0 gL−1 TiO2. Electrochemical syntheses were performed on the carbon steel (CS) elctrode using cyclic voltammetry technique. The terpolymer and nanocomposites were characterized by SEM, EDX, electrochemical impedance spectroscopy (EIS), open circuit potential‐time and anodic polarization techniques. Nanocomposite structures were observed after the addition of TiO2 nanoparticles into terpolymer films and these results was verified via EDX analysis. The results driven by EIS and anodic polarization suggest that, terpolymer and nanocomposite coated electrodes have been shown to have a protective effect against the corrosion of the CS electrode. The nanocomposite coated electrode synthesized in an environment containing 0.4 gL−1 TiO2 was found to have higher corrosion resistance in comparison to uncoated electrode, terpolymer coated electrode and electrodes coated with nanocomposites that is synthesized in environments containing 0.1/1.0 gL−1 TiO2. These results showed that the amount of TiO2 affects the anticorrosive properties of the synthesized nanocomposite.
Synthesis of 2‐Arylbenzoselenazoles from Se‐mediated Redox Condensation of 2‐Chloronitrobenzene and Arylmethyl Chloride
Authors: Gan Haifeng , Cao Mengru , Wu Hongli
Published: April 2020

A selenium‐mediated redox condensation of 2‐chloronitrobenzene and arylmethyl chloride to obtain 2‐arylbenzoselenazoles has been realized under metal‐free condition. The reactions proceeded in moderate‐to‐good yields with good functional compatibility and gram‐scale achievement. Primarily mechanistic investigation suggested that key intermediate Bn(Se)nBn II, was first isolated and confirmed by NMR.
Sulfonylation of Five‐Membered Aromatic Heterocycles Compounds through Nucleophilic Aromatic Substitution: Concerted or Stepwise Mechanism?
Authors: Adolfo Cuesta Sebastián , Cordova‐Sintjago Tania , Ramón Mora José
Published: April 2020

Heterocyclic sulfones are relevant in medicinal chemistry, drug design and organic synthesis, and the mechanism of sulfonylation of five‐membered heterocycles is not clear. In this work, it is presented a computational study on the mechanism of sulfonylation of five‐membered heterocycles compounds. Concerted and stepwise mechanisms for the nucleophilic aromatic substitution (SNAr) involved in the reaction were examined. Effect of the neighbouring group (NG), heteroatom in the ring (HT), nucleophile (NU), and leaving group (LG) in fourteen reactions were examined. Analysis of the intrinsic reaction coordinate, reaction force, natural bond orbital (NBO) charges and bond indexes give a reasonable insight about the mechanism for the reactions studied. Results revealed activation free energies ranging from 20.8 kcal/mol up to 38.6 kcal/mol. Reaction force analysis showed that structural changes in the reactant are the most important component associated with the energy of activation with more than 60 % of the contribution. Most sulfonylation reactions in this study proceed through a concerted mechanism; only two occur though a stepwise‐Meisenheimer‐intermediate mechanism.
An Overview of Microwave‐Assisted Kabachnik‐Fields Reactions
Authors: Shilpa Thomas , Ann Harry Nissy , Ujwaldev Sankuviruthiyil M. , Anilkumar Gopinathan
Published: April 2020

A comprehensive evaluation of MW‐assisted Kabachnik‐Fields reactions (phospha‐Mannich condensation) is done to draw the attention of synthetic chemists towards a greener, solvent‐free and catalyst‐free protocol. The review encompasses the diverse class of α‐aminophosphonates and its derivatives synthesized via one‐pot three component KF reaction, which finds application in various disciplines of chemistry and covers literature up to 2020.
CuO Nanoparticles as a Simple and Efficient Green Catalyst for the Aziridine Ring‐Opening: Examination of a Broad Range of Nucleophiles
Authors: Chatterjee Rana , Santra Sougata , Chakraborty Ghosal Nirnita , Giri Kousik , Zyryanov Grigory V. , Majee Adinath
Published: April 2020

It has been observed that CuO nanoparticles act as effective and reusable catalyst for the ring‐opening reaction of aziridines with a wide range of nucleophiles such as alcohols, thiols, and indoles. The catalytic activity has been tested in large scale reactions. The methodology is applicable in very low catalyst loading. The reaction proceeds under solvent‐free conditions. The catalyst has been used for six consecutive cycles with comparable efficiency. The present methodology could be considered as environmentally benign as indicated by the calculation of E‐factors which are very low in the range of 0.37–1.31.
Crystallinity Variation in Seeded Growth of Gold Nanocrystals: the Role of Additive Ag+
Authors: Zhang Gongguo , Fu Xiaowei , Liu Zhiang , Luan Xiaoqian , Qu Fengli , Zheng Yiqun
Published: April 2020

A synthetic case is reported that demonstrates the cationic additive, Ag+, can influence the crystallinity and thus shape of final product during seeded growth of Au nanocrystals. Using single‐crystal Au seeds as reference, the crystallinity difference between seed and final product could be directly compared. In particular, three different types of crystallinity/morphology can be obtained by varying the concentration of Ag+ in the particle growth solutions: single‐crystal quasi‐spheres, multiply twinned particles (MTPs), and protruded MTPs, with no Ag+ added and solution Ag+ /Au3+ ratios of 1 : 20 and 1 : 5, respectively. The reaction kinetics are investigated using extinction spectroscopy, indicating the presence of Ag+ leads to a dampened growth of Au nanocrystals. This principle is validated using single‐crystal Au seeds with different morphology and amounts. We also test the anti‐corrosion performance of as‐prepared Au nanocrystals with different crystallinity by treating them with sodium thiosulfate. Interestingly, in addition to reduction in size, the morphology of single‐crystal ones varies from quasi‐sphere to cube, indicating the anisotropy in oxidative etching of Au nanocrystals.
Iron‐Catalyzed Synthesis of Polyfunctional Pyridines from Ketoxime Carboxylates and Nitrones
Authors: Jiang Rui , Liu Xiang , Mu Yangxiu , Iqbal Zafar , He Lili , Zhai Lijuan , Hou Jing , Yang Minghua , Yang Zhixiang , Tang Dong
Published: April 2020

Polyfunctional pyridines are backbone of numerous natural products and pharmaceutical reactive intermediates. We have developed an iron‐catalyzed cyclization reaction between ketoxime carboxylates and nitrones to afford trisubstituted pyridines. Employing this strategy, we have synthesized a number of trisubstituted pyridines with various functional groups in good yields under simple reaction conditions. It is worth mentioning that the nitrones can serve as a novel C1 unit in organic synthesis.
Hybridized 2D Nanomaterials Toward Highly Efficient Photocatalysis for Degrading Pollutants: Current Status and Future Perspectives
Authors: Guan Guijian , Ye Enyi , You Mingliang , Li Zibiao
Published: April 2020

Organic pollutants including industrial dyes and chemicals and agricultural waste have become a major environmental issue in recent years. As an alternative to simple adsorption, photocatalytic decontamination is an efficient and energy‐saving technology to eliminate these pollutants from water environment, utilizing the energy of external light, and unique function of photocatalysts. Having a large specific surface area, numerous active sites, and varied band structures, 2D nanosheets have exhibited promising applications as an efficient photocatalyst for degrading organic pollutants, particularly hybridization with other functional components. The novel hybridization of 2D nanomaterials with various functional species is summarized systematically with emphasis on their enhanced photocatalytic activities and outstanding performances in environmental remediation. First, the mechanism of photocatalytic degradation is given for discussing the advantages/shortcomings of regular 2D materials and identifying the importance of constructing hybrid 2D photocatalysts. An overview of several types of intensively investigated 2D nanomaterials (i.e., graphene, g‐C3N4, MoS2, WO3, Bi2O3, and BiOX) is then given to indicate their hybridized methodologies, synergistic effect, and improved applications in decontamination of organic dyes and other pollutants. Finally, future research directions are rationally suggested based on the current challenges.