bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Coronary Artery Calcium Score Using Machine Learning in a Healthy Population
Authors: Lee Jongseok , Lim Jae-Sung , Chu Younggi , Lee Chang Hee , Ryu Ohk-Hyun , Choi Hyun Hee , Park Yong Soon , Kim Chulho
Published: August 2020

Background: Coronary artery calcium score (CACS) is a reliable predictor for future cardiovascular disease risk. Although deep learning studies using computed tomography (CT) images to predict CACS have been reported, no study has assessed the feasibility of machine learning (ML) algorithms to predict the CACS using clinical variables in a healthy general population. Therefore, we aimed to assess whether ML algorithms other than binary logistic regression (BLR) could predict high CACS in a healthy population with general health examination data. Methods: This retrospective observational study included participants who had regular health screening including coronary CT angiography. High CACS was defined by the Agatston score ≥ 100. Univariable and multivariable BLR was performed to assess predictors for high CACS in the entire dataset. When performing ML prediction for high CACS, the dataset was randomly divided into a training and test dataset with a 7:3 ratio. BLR, catboost, and xgboost algorithms with 5-fold cross-validation and grid search technique were used to find the best performing classifier. Performance comparison of each ML algorithm was evaluated with the area under the receiver operating characteristic (AUROC) curve. Results: A total of 2133 participants were included in the final analysis. Mean age and proportion of male sex were 55.4 ± 11.3 years and 1483 (69.5%), respectively. In multivariable BLR analysis, age (odds ratio [OR], 1.12; 95% confidence interval [CI], 1.10–1.15, p < 0.001), male sex (OR, 2.91; 95% CI, 1.57–5.38, p < 0.001), systolic blood pressure (OR, 1.02; 95% CI, 1.00–1.03, p = 0.019), and low-density lipoprotein cholesterol (OR, 1.00; 95% CI, 0.99–1.00, p = 0.047) were significant predictors for high CACS. Performance in predicting high CACS of xgboost was AUROC of 0.823, followed by catboost (0.750) and BLR (0.585). The comparison of AUROC between xgboost and BLR was significant (p for AUROC comparison < 0.001). Conclusions: Xgboost ML algorithm was found to be a more reliable predictor of CACS in healthy participants compared to the BLR algorithm. ML algorithms may be useful for predicting CACS with only laboratory data in healthy participants.
Exploring Forest Change Spatial Patterns in Papua New Guinea: A Pilot Study in the Bumbu River Basin
Authors: Doaemo Willie , Mohan Midhun , Adrah Esmaeel , Srinivasan Shruthi , Dalla Corte Ana Paula
Published: August 2020

Papua New Guinea is a country in Oceania that hosts unique rain forests and forest ecosystems which are crucial for sequestering atmospheric carbon, conserving biodiversity, supporting the livelihood of indigenous people, and underpinning the timber market of the country. As a result of urban sprawl, agricultural expansion, and illegal logging, there has been a tremendous increase in land-use land cover (LULC) change happening in the country in the past few decades and this has triggered massive deforestation and forest degradation. However, only a few studies have ventured into quantifying the long-term trends and their associated spatial patterns—and have often presented contrasting responses. Herein, we intended to assess the extent of deforestation and the rate of urbanization that happened in the past 33 years (1987–2020) in the Bumbu river basin in Papua New Guinea using satellite imagery—for the years 1987, 2002, 2010, and 2020—and Geographic Information System (GIS) tools. On performing image classification, land use maps were developed and later compared with Google Earth’s high-resolution satellite images for accuracy assessment purposes. For probing into the spatial aspects of the land-use change issues, the study area was divided into four urban zones and four forest zones according to the four main cardinal directions centered in the urban and forest area centers of the 1987 image; subsequently, the rate of urban area expansion in each urban zone was separately calculated. From our preliminary analysis and literature survey, we observed several hurdles regarding the classification of regenerative forests and mixed pixels and gaps in LULC studies that have happened in Papua New Guinea to date. Through this communication paper, we aim to disseminate our preliminary results, which highlight a rapid increase in urban extent from 14.39 km2 in 1987 to 23.06 km2 in 2020 accompanied by a considerable decrease in forest extent from 76.29 km2 in 1987 to 59.43 km2 in 2020; this observation favors the presumption that urban and agricultural land expansion is happening at the cost of forest cover. Moreover, strategies for addressing technical issues and for integrating land-use change with various socioeconomic and environmental variables are presented soliciting feedback.
Allées in Landscape Architecture and Garden Art—Types, Preservation, and Renewal of the Living Heritage of Baroque Allées in Hungary
Authors: Szilágyi Kinga , Lahmer Chaima , Szabó Krisztina
Published: August 2020

Examining the history of garden art since ancient times, we find many examples of linear tree layouts supporting orientation or being used for the purpose of composition. Allées gained special significance during the Baroque as dynamic and grandiose space-forming garden design elements. They mostly consist of trees of taxonomically similar species planted along a regular line equidistant from each other in single or multiple rows. The two-dimensional compositional elements of the layout form three-dimensional longitudinal space forms. During their evolution, both their proportions and openness constantly change. Analyses of the compositional role and functions of allées of exemplary Hungarian Baroque garden complexes in the 18th century provided a basis for setting up a novel typology. Five compositional types have been defined as the primary result of archival research. The significance of the still-subsisting historic Hungarian allées calls for unique protection similar to European heritage protection. Taking a summary of significant, surviving examples of Hungarian Baroque allées into account, methods for allée renewal are defined along with the core question of whether allées are natural landscape elements or strict architectural compositions where authenticity may be an important criterion. The methodological research is partially based on three plans for the renewal of Baroque allées in Hungary that have been worked out by the Author as the chief landscape architect of the projects.
Electrical Conduction Characteristic of a 2D MXene Device with Cu/Cr2C/TiN Structure Based on Density Functional Theory
Authors: Wang Lei , Wen Jing , Jiang Yuan , Ou Qiaofeng , Yu Lei , Xiong Bang-Shu , Yang Bingxing , Zhang Chao , Tong Yi
Published: August 2020

The electronic structure and the corresponding electrical conductive behavior of the Cu/Cr2C/TiN stack were assessed according to a newly developed first-principle model based on density functional theory. Using an additional Cr2C layer provides the metal-like characteristic of the Cu/Cr2C/TiN stack with much larger electrical conduction coefficients (i.e., mobility, diffusivity, and electrical conductivity) than the conventional Ag/Ti3C2/Pt stack due to the lower activation energy. This device is therefore capable of offering faster switching speeds, lower programming voltage, and better stability and durability than the memristor device with conventional Ti3C2 MXene.
Stability Assessment of Stochastic Differential-Algebraic Systems via Lyapunov Exponents with an Application to Power Systems
Authors: González-Zumba Andrés , Fernández-de-Córdoba Pedro , Cortés Juan-Carlos , Mehrmann Volker
Published: August 2020

In this paper, we discuss stochastic differential-algebraic equations (SDAEs) and the asymptotic stability assessment for such systems via Lyapunov exponents (LEs). We focus on index-1 SDAEs and their reformulation as ordinary stochastic differential equations (SDEs). Via ergodic theory, it is then feasible to analyze the LEs via the random dynamical system generated by the underlying SDEs. Once the existence of well-defined LEs is guaranteed, we proceed to the use of numerical simulation techniques to determine the LEs numerically. Discrete and continuous QR decomposition-based numerical methods are implemented to compute the fundamental solution matrix and use it in the computation of the LEs. Important computational features of both methods are illustrated via numerical tests. Finally, the methods are applied to two applications from power systems engineering, including the single-machine infinite-bus (SMIB) power system model.
In Vivo Biological Evaluation of Orthodontically Moved Incisors after Replantation
Authors: Calasans-Maia Jose de Albuquerque , Calasans-Maia Monica Diuana , Stuani Maria Bernadete Sasso , Alves Adriana Terezinha Neves Novellino , Montemezzi Pietro , Mourão Carlos Fernando de Almeida Barros , Cal-Neto Julio Pedra e , Ruellas Antonio Carlos de Oliviera
Published: August 2020

Background and Objectives: There is still considerable controversy regarding the possibility of submitting replanted teeth to orthodontic movement (OM). The purpose of the present study was to evaluate the tissue response after orthodontic movement on replanted teeth. Materials and Methods: Sixty Wistar rats were randomly assigned to four groups (n = 15): G1, replantation without OM after 30 days; G2, replantation with OM after 30 days; G3, replantation without OM after 60 days, and G4, replantation with OM after 60 days. The maxillary left central incisors were extracted and the teeth were stored in milk media. After 30 min, the teeth were replanted and fixed with non-rigid immobilization. All specimens were observed after 30 and 60 days of replantation and then subdivided into two subgroups (with OM or without OM). The animals were euthanized after seven days of the OM started, and the maxillary bone blocks were processed for histological evaluation. Results: The histological results showed periodontal ligament repair in both periods studied without OM; however, ankylosis and root resorption was seen in all orthodontically moved teeth. Conclusions: The orthodontic movement did not favor tissue response in all replanted teeth, regardless of the experimental periods.
Dimensional Nanofillers in Mixed Matrix Membranes for Pervaporation Separations: A Review
Authors: Yang Guang , Xie Zongli , Cran Marlene , Wu Chunrui , Gray Stephen
Published: August 2020

Pervaporation (PV) has been an intriguing membrane technology for separating liquid mixtures since its commercialization in the 1980s. The design of highly permselective materials used in this respect has made significant improvements in separation properties, such as selectivity, permeability, and long-term stability. Mixed-matrix membranes (MMMs), featuring inorganic fillers dispersed in a polymer matrix to form an organic–inorganic hybrid, have opened up a new avenue to facilely obtain high-performance PV membranes. The combination of inorganic fillers in a polymer matrix endows high flexibility in designing the required separation properties of the membranes, in which various fillers provide specific functions correlated to the separation process. This review discusses recent advances in the use of nanofillers in PV MMMs categorized by dimensions including zero-, one-, two- and three-dimensional nanomaterials. Furthermore, the impact of the nanofillers on the polymer matrix is described to provide in-depth understanding of the structure–performance relationship. Finally, the applications of nanofillers in MMMs for PV separation are summarized.
Synthesis and Characterization of Novel Integral Asymmetric Monophasic Cellulose–Acetate/Silica/Titania and Cellulose–Acetate/Titania Membranes
Authors: Peixoto Inês , Faria Mónica , Gonçalves M. Clara
Published: August 2020

Two series of novel integral asymmetric monophasic hybrid membranes, cellulose acetate/silica/titania (CA/SiO2/TiO2—series 1) and cellulose acetate/titania (CA/TiO2—series 2), were developed by the coupling of sol-gel technology and a modified version of the phase inversion technique. SEM micrographs confirmed the integral asymmetric structure of all membranes. ATR-FTIR and ICP-OES results showed that, for the membranes in series 1, TiO2 is covalently bound to SiO2, which, in turn, is covalently bound to CA, while for the membranes in series 2, TiO2 is directly and covalently bound to the CA matrix. Permeation experiments revealed that the permeation performance of the membranes in series 1 is unaffected by the introduction of TiO2. In contrast, the introduction of TiO2 in the series 2 membranes increased the hydraulic permeability by a factor of at least 2 when compared to the pristine CA membrane and that incremental additions of TiO2 further increased the Lp.
Numerical Prediction and Reduction of Hat-Shaped Part Springback Made of Dual-Phase AHSS Steel
Authors: Mulidrán Peter , Spišák Emil , Tomáš Miroslav , Slota Ján , Majerníková Janka
Published: August 2020

The springback in the sheet metal forming process refers to the change of shape after the load removal. It is usually undesirable, causing problems in the subsequent forming operations, in the assembly and negatively affects the quality of the final product. Numerical prediction of the springback with the use of the numerical simulation is crucial for the reduction of forming tool try-outs, reducing manufacturing costs and increasing the accuracy of the stamped part. In this work, numerical simulation was used for the springback prediction of the hat-shaped part made of advanced high-strength dual-phase steel HCT600X+Z. These numerical predictions were performed with the use of various combinations of material models to try to improve the prediction results. Furthermore, this work includes the proposed springback reduction measure. The reduction of the springback was achieved by the tool design which includes a counterpunch. The springback analysis was carried out in the side view of the formed part; the springback prediction results were compared with the experimental values.
Genome Sequence of Trichoderma lixii MUT3171, A Promising Strain for Mycoremediation of PAH-Contaminated Sites
Authors: Venice Francesco , Davolos Domenico , Spina Federica , Poli Anna , Prigione Valeria Paola , Varese Giovanna Cristina , Ghignone Stefano
Published: August 2020

Mono- and polycyclic aromatic hydrocarbons (PAHs) are widespread and recalcitrant pollutants that threaten both environmental and human health. By exploiting the powerful enzymatic machinery of fungi, mycoremediation in contaminated sites aims at removing a wide range of pollutants in a cost-efficient and environmentally friendly manner. Next-generation sequencing (NGS) techniques are powerful tools for understanding the molecular basis of biotransformation of PAHs by selected fungal strains, allowing genome mining to identify genetic features of biotechnological value. Trichoderma lixii MUT3171, isolated from a historically PAH-contaminated soil in Italy, can grow on phenanthrene, as a sole carbon source. Here, we report the draft genome sequence of T. lixii MUT3171 obtained with high-throughput sequencing method. The genome of T. lixii MUT3171 was compared with other 14 Trichoderma genomes, highlighting both shared and unique features that can shed a light on the biotransformation of PAHs. Moreover, the genes potentially involved in the production of important biosurfactants and bioactive molecules have been investigated. The gene repertoire of T. lixii MUT3171 indicates a high degrading potential and provides hints on putative survival strategies in a polluted environment.
Resilience of Aspergillus westerdijkiae Strains to Interacting Climate-Related Abiotic Factors: Effects on Growth and Ochratoxin A Production on Coffee-Based Medium and in Stored Coffee
Authors: Akbar Asya , Medina Angel , Magan Naresh
Published: August 2020

We examined the resilience of strains of Aspergillus westerdijkiae in terms of growth and ochratoxin A (OTA) production in relation to: (a) two-way interacting climate-related abiotic factors of water activity (aw, 0.99–0.90) × temperature (25–37 °C) on green coffee and roasted coffee-based media; (b) three-way climate-related abiotic factors (temperature, 30 vs. 35 °C; water stress, 0.98–0.90 aw; CO2, 400 vs. 1000 ppm) on growth and OTA production on a 6% green coffee extract-based matrix; and (c) the effect of three-way climate-related abiotic factors on OTA production in stored green coffee beans. Four strains of A. westerdijkiae grew equally well on green or roasted coffee-based media with optimum 0.98 aw and 25–30 °C. Growth was significantly slower on roasted than green coffee-based media at 35 °C, regardless of aw level. Interestingly, on green coffee-based media OTA production was optimum at 0.98–0.95 aw and 30 °C. However, on roasted coffee-based media very little OTA was produced. Three-way climate-related abiotic factors were examined on two of these strains. These interacting factors significantly reduced growth of the A. westerdijkiae strains, especially at 35 °C × 1000 ppm CO2 and all aw levels when compared to 30 °C. At 35 °C × 1000 ppm CO2 there was some stimulation of OTA production by the two A. westerdijkiae strains, especially under water stress. In stored green coffee beans optimum OTA was produced at 0.95–0.97 aw/30 °C. In elevated CO2 and 35 °C, OTA production was stimulated at 0.95–0.90 aw.
An LSTM Approach for SAG Mill Operational Relative-Hardness Prediction
Authors: Avalos Sebastian , Kracht Willy , Ortiz Julian
Published: August 2020

Ore hardness plays a critical role in comminution circuits. Ore hardness is usually characterized at sample support in order to populate geometallurgical block models. However, the required attributes are not always available and suffer for lack of temporal resolution. We propose an operational relative-hardness definition and the use of real-time operational data to train a Long Short-Term Memory, a deep neural network architecture, to forecast the upcoming operational relative-hardness. We applied the proposed methodology on two SAG mill datasets, of one year period each. Results show accuracies above 80% on both SAG mills at a short upcoming period of times and around 1% of misclassifications between soft and hard characterization. The proposed application can be extended to any crushing and grinding equipment to forecast categorical attributes that are relevant to downstream processes.
The Cyclops Ophiolite as a Source of High-Cr Spinels from Marine Sediments on the Jayapura Regency Coast (New Guinea, Indonesia)
Authors: Zglinicki Karol , Szamałek Krzysztof , Górska Irena
Published: August 2020

The first detailed mineralogy, geochemistry and origin of heavy minerals in marine sediments along the Jayapura Regency coast on the Indonesian part of New Guinea Island are reported as part of a larger set of investigations conducted since 2009. In these sediments, the following heavy minerals were identified: high-Al and high-Cr spinels, chromian andradite, Mg-olivine, magnetite, mixture of iron (III) oxyhydroxides (limonite) and minerals from serpentine-group minerals (lizardite, antigorite). The heavy mineral fraction of marine sediments contains increased concentrations of metals, including W (up to 257.72 ppm) and Ag (up to 1330.29 ppb) as well as minor amounts of Ni (7.1–3560.9 ppm) and Cr (68.0–5816.0 ppm). The present state of geological knowledge suggests that there are no known prospects for rich Ti, Ni, Co, Cr, Au deposits along the examined part of the Jayapura coast. However, the average content of Ag and W is high enough to provide an impulse for suggested further deposit research. The source of marine sediments is Cyclops ophiolite, which contains a typical ophiolite sequence. Cyclops Mountain rocks have undergone intense chemical weathering processes and the resulting eroded material has been deposited on the narrow continental shelf. The chemical composition of chromian spinels indicates that their source is depleted peridotites from the SSZ (supra-subduction zone) environment of the Cyclops ophiolite. A detailed geochemical examination indicates that the evolution of parental melt of these rocks evolved towards magma with geochemical parameters similar to mid-ocean ridge basalt (MORB).
Characterization of Volatile Organic Compounds Emitted from Endophytic Burkholderia cenocepacia ETR-B22 by SPME-GC-MS and Their Inhibitory Activity against Various Plant Fungal Pathogens
Authors: Chen Jian-Hua , Xiang Wei , Cao Ke-Xin , Lu Xuan , Yao Shao-Chang , Hung Ding , Huang Rong-Shao , Li Liang-Bo
Published: August 2020

The use of antagonistic microorganisms and their volatile organic compounds (VOCs) to control plant fungal pathogens is an eco-friendly and promising substitute for chemical fungicides. In this work, endophytic bacterium ETR-B22, isolated from the root of Sophora tonkinensis Gagnep., was found to exhibit strong antagonistic activity against 12 fungal pathogens found in agriculture. Strain ETR-B22 was identified as Burkholderia cenocepacia based on 16S rRNA and recA sequences. We evaluated the antifungal activity of VOCs emitted by ETR-B22. The VOCs from strain ETR-B22 also showed broad-spectrum antifungal activity against 12 fungal pathogens. The composition of the volatile profiles was analyzed based on headspace solid phase microextraction (HS-SPME) gas chromatography coupled to mass spectrometry (GC-MS). Different extraction strategies for the SPME process significantly affected the extraction efficiency of the VOCs. Thirty-two different VOCs were identified. Among the VOC of ETR-B22, dimethyl trisulfide, indole, methyl anthranilate, methyl salicylate, methyl benzoate, benzyl propionate, benzyl acetate, 3,5-di-tert-butylphenol, allyl benzyl ether and nonanoic acid showed broad-spectrum antifungal activity, and are key inhibitory compounds produced by strain ETR-B22 against various fungal pathogens. Our results suggest that the endophytic strain ETR-B22 and its VOCs have high potential for use as biological controls of plant fungal pathogens.
Metathesis Cyclopolymerization Triggered Self-Assembly of Azobenzene-Containing Nanostructure
Authors: Song Wei , Shen Jiamin , Li Xiang , Huang Jinhui , Ding Liang , Wu Jianhua
Published: August 2020

Azobenzene (AB) units were successfully introduced into poly(1,6-heptadiyne)s in order to ensure smooth synthesis of double- and single-stranded poly(1,6-heptadiyne)s (P1 and P2) and simultaneously realize the self-assembly by Grubbs-III catalyst-mediated metathesis cyclopolymerization (CP) of AB-functionalized bis(1,6-heptadiyne) and 1,6-heptadiyne monomers (M1 and M2). Monomers and polymers were characterized by 1H NMR, mass spectroscopy, and GPC techniques. The double-stranded poly(1,6-heptadiyne)s exhibited a large scale of ordered ladder nanostructure. This result was attributed to the π−π attractions between end groups along the longitudinal axis of the polymers and van der Waals interactions between the neighboring polymeric backbones. While the Azo chromophore connected in the side chain of P2 induced conformation of micelles nanostructure during the CP process without any post-treatment. Furthermore, the photoisomerization of Azo units had an obviously different regulatory effect on the conjugated degree of the polymer backbone, especially for the single-stranded P2, which was attributed to the structural differences and the interaction between AB chromophores in the polymers.
Synthesis of 2-((2-(Benzo[d]oxazol-2-yl)-2H-imidazol-4-yl)amino)-phenols from 2-((5H-1,2,3-Dithiazol-5-ylidene)amino)phenols through Unprecedented Formation of Imidazole Ring from Two Methanimino Groups
Authors: Baranovsky Ilia V. , Konstantinova Lidia S. , Tolmachev Mikhail A. , Popov Vadim V. , A. Lyssenko Konstantin , Rakitin Oleg A.
Published: August 2020

A new synthetic pathway to four substituted imidazoles from readily available 2-((4-aryl(thienyl)-5H-1,2,3-dithiazol-5-ylidene)amino)phenols has been developed. Benzo[d]oxazol-2-yl(aryl(thienyl))methanimines were proved as key intermediates in their synthesis. The formation of an imidazole ring from two methanimine derivatives likely includes the opening of one benzoxazole ring followed by ring closure by intermolecular nucleophilic attack of the N-methanimine atom to a carbon atom of another methanimine.
Piceatannol, a Natural Analog of Resveratrol, Exerts Anti-angiogenic Efficiencies by Blockage of Vascular Endothelial Growth Factor Binding to Its Receptor
Authors: Hu Wei-Hui , Dai Diana Kun , Zheng Brody Zhong-Yu , Duan Ran , Dong Tina Ting-Xia , Qin Qi-Wei , Tsim Karl Wah-Keung
Published: August 2020

Piceatannol is also named as trans-3,4,3′,5′-tetrahydroxy-stilbene, which is a natural analog of resveratrol and a polyphenol existing in red wine, grape and sugar cane. Piceatannol has been proved to possess activities of immunomodulatory, anti-inflammatory, antiproliferative and anticancer. However, the effect of piceatannol on VEGF-mediated angiogenesis is not known. Here, the inhibitory effects of piceatannol on VEGF-induced angiogenesis were tested both in vitro and in vivo models of angiogenesis. In human umbilical vein endothelial cells (HUVECs), piceatannol markedly reduced the VEGF-induced cell proliferation, migration, invasion, as well as tube formation without affecting cell viability. Furthermore, piceatannol significantly inhibited the formation of subintestinal vessel in zebrafish embryos in vivo. In addition, we identified the underlying mechanism of piceatannol in triggering the anti-angiogenic functions. Piceatannol was proposed to bind with VEGF, thus attenuating VEGF in activating VEGF receptor and blocking VEGF-mediated downstream signaling, including expressions of phosphorylated eNOS, Erk and Akt. Furthermore, piceatannol visibly suppressed ROS formation, as triggered by VEGF. Moreover, we further determined the outcome of piceatannol binding to VEGF in cancer cells: piceatannol significantly suppressed VEGF-induced colon cancer proliferation and migration. Thus, these lines of evidence supported the conclusion that piceatannol could down regulate the VEGF-mediated angiogenic functions with no cytotoxicity via decreasing the amount of VEGF binding to its receptors, thus affecting the related downstream signaling. Piceatannol may be developed into therapeutic agents or health products to reduce the high incidence of angiogenesis-related diseases.
13C CPMAS NMR as a Tool for Full Structural Description of 2-Phenyl Substituted Imidazoles That Overcomes the Effects of Fast Tautomerization
Authors: Burdzhiev Nikola , Ahmedova Anife , Borrisov Boris , Graf Robert
Published: August 2020

Tautomerization of 2-phenylimidazolecarbaldehydes has not been studied in detail so far, although this process is a well-known phenomenon for imidazole derivatives. That is why we focus our study on a series of 2-phenylimidazolecarbaldehydes and their parent alcohols that were synthesized and studied by detailed 1H and 13C NMR in solution and in the solid state. The apparent problem is that the fast tautomerization impedes the full structural description of the compounds by conventional 13C NMR measurements. Indeed, the 13C NMR spectra in solution exhibit poor resolution, and in most cases, signals from the imidazole ring are not detectable. To avoid this problem, we used 13C CP-MAS NMR as an alternative spectroscopic method for unambiguous spectroscopic characterization of the studied series of 2-phenylimidazoles. The data were analyzed in combination with quantum chemical DFT-GIAO methods by considering the tautomerization process and the intermolecular interactions. The DFT (B3LYP/6-31G(d,p)) calculations allowed to identify and suggest the preferred tautomer in the gas phase and in DMSO solvent, which for alcohols are (2-phenyl-1H-imidazol-4-yl)methanol and its analogs, and for the aldehydes are the 2-phenyl-1H-imidazole-5-carbaldehydes. The gas-phase calculated energy differences between the two possible tautomeric forms are in the range 0.645–1.415 kcal/mol for the alcohols and 2.510–3.059 kcal/mol for the aldehydes. In the DMSO solvent, however, for all compounds, the calculated energy differences go below 1.20 kcal/mol. These data suggest that both tautomeric forms of the studied 2-phenylimidazoles can be present in solution at room temperature. Our data from detailed 2D NMR measurements in the solid state (1H-13C HETCOR and 1H-1H double-quantum coherence MAS NMR) suggested that also in the solid state both tautomers coexist in different crystalline domains. This fact does not obscure the 13C CP-MAS NMR spectra of the studied 2-phenyl substituted imidazoles and suggests this spectroscopic method as a powerful tool for a complete structural description of tautomeric systems with aromatic conjugation.
Comparative Analysis of Far East Sikhotinsky Rhododendron (Rh. sichotense) and East Siberian Rhododendron (Rh. adamsii) Using Supercritical CO2-Extraction and HPLC-ESI-MS/MS Spectrometry
Authors: Razgonova Mayya , Zakharenko Alexander , Ercisli Sezai , Grudev Vasily , Golokhvast Kirill
Published: August 2020

Rhododendron sichotense Pojark. and Rhododendron adamsii Rheder have been actively used in ethnomedicine in Mongolia, China and Buryatia (Russia) for centuries, as an antioxidant, immunomodulating, anti-inflammatory, vitality-restoring agent. These plants contain various phenolic compounds and fatty acids with valuable biological activity. Among green and selective extraction methods, supercritical carbon dioxide (SC-CO2) extraction has been shown to be the method of choice for the recovery of these naturally occurring compounds. Operative parameters and working conditions have been optimized by experimenting with different pressures (300–400 bar), temperatures (50–60 °C) and CO2 flow rates (50 mL/min) with 1% ethanol as co-solvent. The extraction time varied from 60 to 70 min. A HPLC-UV-VIS-ESI-MS/MS technique was applied to detect target analytes. A total of 48 different biologically active components have been identified in the Rh. adamsii SC-CO2 extracts. A total of 31 different biologically active components have been identified in the Rh. sichotense SC-CO2 extracts.
Synthesis and Structure of Iron (II) Complexes of Functionalized 1,5-Diaza-3,7-Diphosphacyclooctanes
Authors: Spiridonova Yulia S. , Nikolaeva Yulia A. , Balueva Anna S. , Musina Elvira I. , Litvinov Igor A. , Strelnik Igor D. , Khrizanforova Vera V. , Budnikova Yulia G. , Karasik Andrey A.
Published: August 2020

In order to synthesize new iron (II) complexes of 1,5-diaza-3,7-diphosphacyclooctanes with a wider variety of the substituents on ligands heteroatoms (including functionalized ones, namely, pyridyl groups) and co-ligands, it was found that these ligands with relatively small phenyl, benzyl, and pyridin-2-yl substituents on phosphorus atoms in acetonitrile formed bis-P,P-chelate cis-complexes [L2Fe(CH3CN)2]2+ (BF4)2−, whereas P-mesityl-substituted ligand formed only monoligand P,P-complex [LFe(CH3CN)4]2+ (BF4)2−. 3,7-dibenzyl-1,5-di(1′-(R)-phenylethyl)-1,5-diaza-3,7-diphosphacyclooctane reacted with hexahydrate of iron (II) tetrafluoroborate in acetone to give an unusual bis-ligand cationic complex of the composition [L2Fe(BF4)]+ BF4−, where two fluorine atoms of the tetrafluoroborate unit occupied two pseudo-equatorial positions at roughly octahedral iron ion, according to X-ray diffraction data. 1,5-diaza-3,7-diphosphacyclooctanes replaced tetrahydrofurane and one of the carbonyl ligands of cyclopentadienyldicarbonyl(tetrahydrofuran)iron (II) tetrafluoroborate to form heteroligand complexes [CpFeL(CO)]+BF4−. The structural studies in the solid phase and in solutions showed that diazadiphosphacyclooctane ligands of all complexes adopted chair-boat conformations so that their nitrogen atoms were in close proximity to the central iron ion. The redox properties of the obtained complexes were performed by the cyclic voltammetry method.
Copper(II) Complexes with Mixed Heterocycle Ligands as Promising Antibacterial and Antitumor Species
Authors: Rostas Arpad Mihai , Badea Mihaela , Ruta Lavinia L. , Farcasanu Ileana C. , Maxim Catalin , Chifiriuc Mariana Carmen , Popa Marcela , Luca Mirela , Celan Korosin Natasa , Cerc Korosec Romana , Bacalum Mihaela , Raileanu Mina , Olar Rodica
Published: August 2020

Complexes with mixed ligands [Cu(N-N)2(pmtp)](ClO4)2 ((1) N-N: 2,2′-bipyridine; (2) L: 1,10-phenanthroline and pmpt: 5-phenyl-7-methyl-1,2,4-triazolo[1,5-a]pyrimidine) were synthesized and structurally and biologically characterized. Compound (1) crystallizes into space group Pa and (2) in P-1. Both complexes display an intermediate stereochemistry between the two five-coordinated ones. The biological tests indicated that the two compounds exhibited superoxide scavenging capacity, intercalative DNA properties, and metallonuclease activity. Tests on various cell systems indicated that the two complexes neither interfere with the proliferation of Saccharomyces cerevisiae or BJ healthy skin cells, nor cause hemolysis in the active concentration range. Nevertheless, the compounds showed antibacterial potential, with complex (2) being significantly more active than complex (1) against all tested bacterial strains, both in planktonic and biofilm growth state. Both complexes exhibited a very good activity against B16 melanoma cells, with a higher specificity being displayed by compound (1). Taken together, the results indicate that complexes (1) and (2) have specific biological relevance, with potential for the development of antitumor or antimicrobial drugs.
Composition of Primary and Secondary Metabolite Compounds in Seeds and Pods of Asparagus Bean (Vigna unguiculata (L.) Walp.) from China
Authors: Perchuk Irina , Shelenga Tatyana , Gurkina Maria , Miroshnichenko Elena , Burlyaeva Marina
Published: August 2020

Asparagus bean immature pods and seeds are popular as food products for healthy and functional nutrition. Gas chromatography with mass spectrometry was used to compare metabolomic profiles of seeds and pods yielded by old Chinese landraces and the modern cultivars ‘Yunanskaya’ and ‘Sibirskiy razmer’. About 120 compounds were identified. The content of a majority among groups of compounds was higher in pods than in seeds. The amount of free amino acids in pods was 47 times higher, polyols and phytosterols 5 times higher, phenolics 4 times higher, and organic acids and saponins 3 times higher than in seeds. Differences were found in the relative content of compounds. Among phenolic compounds, the dominant one for seeds was protocatechuic acid, and for pods 4-hydroxycinnamic acid. Only polyols were identified in seeds, but pods additionally contained ethanolamine, phytol, and phytosphingosine. The ratio for nonsaturated/saturated fatty acids was 2.2 in seeds and 1.4 in pods. Seeds contained more stigmasterol, and pods more β-sitosterol. Aglycones of saponins were identified: cycloartenol in seeds, α- and β-amyrins in pods. Oligosaccharides dominated in both seeds and pods. Landraces manifested higher protein content in pods, while modern cultivars had pods with higher contents of organic acids, polyols, monosaccharides, and fatty acids. The results obtained confirm the high nutritional value of asparagus bean seeds and pods, and the prospects of their use in various diets.
Synthesis of Hierarchical Porous Ni1.5Co1.5S4/g-C3N4 Composite for Supercapacitor with Excellent Cycle Stability
Authors: Jin Fangzhou , He Xingxing , Jiang Jinlong , Zhu Weijun , Dai Jianfeng , Yang Hua
Published: August 2020

In this work, the hierarchical porous Ni1.5Co1.5S4/g-C3N4 composite was prepared by growing Ni1.5Co1.5S4 nanoparticles on graphitic carbon nitride (g-C3N4) nanosheets via a hydrothermal route. Due to the self-assembly of larger size g-C3N4 nanosheets as a skeleton, the prepared nanocomposite possesses a unique hierarchical porous structure that can provide short ions diffusion and fast electron transport. As a result, the Ni1.5Co1.5S4/g-C3N4 composite exhibits a high specific capacitance of 1827 F g−1 at a current density of 1 A g−1, which is 1.53 times that of pure Ni1.5Co1.5S4 (1191 F g−1). In particular, the Ni1.5Co1.5S4/g-C3N4//activated carbon (AC) asymmetric supercapacitor delivers a high energy density of 49.0 Wh kg−1 at a power density of 799.0 W kg−1. Moreover, the assembled device shows outstanding cycle stability with 95.5% capacitance retention after 8000 cycles at a high current density of 10 A g−1. The attractive performance indicates that the easily synthesized and low-cost Ni1.5Co1.5S4/g-C3N4 composite would be a promising electrode material for supercapacitor application.
Hydroxyapatite and Titanium Dioxide Nanoparticles: Radiolabelling and In Vitro Stability of Prospective Theranostic Nanocarriers for 223Ra and 99mTc
Authors: Suchánková Petra , Kukleva Ekaterina , Nykl Eva , Nykl Pavel , Sakmár Michal , Vlk Martin , Kozempel Ján
Published: August 2020

Hydroxyapatite and titanium dioxide are widely used materials in a broad spectrum of branches. Due to their appropriate properties such as a large specific surface area, radiation stability or relatively low toxicity, they could be potentially used as nanocarriers for medicinal radionuclides for diagnostics and therapy. Two radiolabelling strategies of both nanomaterials were carried out by 99mTc for diagnostic purposes and by 223Ra for therapeutic purposes. The first one was the radionuclide sorption on ready-made nanoparticles and the second one was direct radionuclide incorporation into the structure of the nanoparticles. Achieved labelling yields were higher than 94% in all cases. Afterwards, in vitro stability tests were carried out in several solutions: physiological saline, bovine blood plasma, bovine blood serum, 1% and 5% human albumin solutions. In vitro stability studies were performed as short-term (59 h for 223Ra and 31 h for 99mTc) and long-term experiments (five half-lives of 223Ra, approx. 55 days). Both radiolabelled nanoparticles with 99mTc have shown similar released activities (about 20%) in all solutions. The best results were obtained for 223Ra radiolabelled titanium dioxide nanoparticles, where overall released activities were under 6% for 59 h study in all matrices and under 3% for 55 days in a long-term perspective.
3D Hollow rGO Microsphere Decorated with ZnO Nanoparticles as Efficient Sulfur Host for High-Performance Li-S Battery
Authors: Zhang Zhi , Yi Zichuan , Liu Liming , Yang Jianjun , Zhang Chongfu , Pan Xinjian , Chi Feng
Published: August 2020

Lithium-sulfur battery (LSB) will become the next generation energy storage device if its severe shuttle effect and sluggish redox kinetics can be effectively addressed. Here, a unique three-dimensional hollow reduced graphene oxide microsphere decorated with ZnO nanoparticles (3D-ZnO/rGO) is synthesized to decrease the dissolution of lithium polysulfide (LiPS) into the electrolyte. The chemical adsorption of ZnO on LiPS is combined with the physical adsorption of 3D-rGO microsphere to synergistically suppress the shuttle effect. The obtained 3D-ZnO/rGO can provide sufficient space for sulfur storage, and effectively alleviate the repeated volume changes of sulfur during the cycle. When the prepared S-3D-ZnO/rGO was used as the cathode in LSB, an initial discharge specific capacity of 1277 mAh g−1 was achieved at 0.1 C. After 100 cycles, 949 mAh g−1 can still be maintained. Even at 1 C, a reversible discharge specific capacity of 726 mAh g−1 was delivered.
Electrochemical Impedance Spectroscopy Analysis of Hole Transporting Material Free Mesoporous and Planar Perovskite Solar Cells
Authors: Abdulrahim Sumayya M. , Ahmad Zubair , Bahadra Jolly , Al-Thani Noora J.
Published: August 2020

The future photovoltaic technologies based on perovskite materials are aimed to build low tech, truly economical, easily fabricated, broadly deployable, and trustworthy solar cells. Hole transport material (HTM) free perovskite solar cells (PSCs) are among the most likely architectures which hold a distinctive design and provide a simple way to produce large-area and cost-effective manufacture of PSCs. Notably, in the monolithic scheme of the HTM-free PSCs, all layers can be printed using highly reproducible and morphology-controlled methods, and this design has successfully been demonstrated for industrial-scale fabrication. In this review article, we comprehensively describe the recent advancements in the different types of mesoporous (nanostructured) and planar HTM-free PSCs. In addition, the effect of various nanostructures and mesoporous layers on their performance is discussed using the electrochemical impedance spectroscopy (EIS) technique. We bring together the different perspectives that researchers have developed to interpret and analyze the EIS data of the HTM-free PSCs. Their analysis using the EIS tool, the limitations of these studies, and the future work directions to overcome these limitations to enhance the performance of HTM-free PSCs are comprehensively considered.
“Fast” Plasmons Propagating in Graphene Plasmonic Waveguides with Negative Index Metamaterial Claddings
Authors: Zhao Zeyang , Su Shaojian , Zhou Hengjie , Qiu Weibin , Qiu Pingping , Kan Qiang
Published: August 2020

We propose the monolayer graphene plasmonic waveguide (MGPW), which is composed of graphene core sandwiched by two graphene metamaterial (GMM) claddings and investigate the properties of plasmonic modes propagating in the waveguide. The effective refraction index of the GMMs claddings takes negative (or positive) at the vicinity of the Dirac-like point in the band structure. We show that when the effective refraction index of the GMMs is positive, the plasmons travel forward in the MGPW with a positive group velocity (vg > 0, vp > 0). In contrast—for the negative refraction index GMM claddings—a negative group velocity of the fundamental mode (vg < 0, vp > 0) appears in the proposed waveguide structure when the core is sufficiently narrow. A forbidden band appears between the negative and positive group velocity regions, which is enhanced gradually as the width of the core increases. On the other hand, one can overcome this limitation and even make the forbidden band disappear by increasing the chemical potential difference between the nanodisks and the ambient graphene of the GMM claddings. The proposed structure offers a novel scheme of on-chip electromagnetic field and may find significant applications in the future high density plasmonic integrated circuit technique.
Graphene Oxide-Based Silico-Phosphate Composite Films for Optical Limiting of Ultrashort Near-Infrared Laser Pulses
Authors: Petris Adrian , Vasiliu Ileana Cristina , Gheorghe Petronela , Iordache Ana Maria , Ionel Laura , Rusen Laurentiu , Iordache Stefan , Elisa Mihai , Trusca Roxana , Ulieru Dumitru , Etemadi Samaneh , Wendelbo Rune , Yang Juan , Thorshaug Knut
Published: August 2020

The development of graphene-based materials for optical limiting functionality is an active field of research. Optical limiting for femtosecond laser pulses in the infrared-B (IR-B) (1.4–3 μm) spectral domain has been investigated to a lesser extent than that for nanosecond, picosecond and femtosecond laser pulses at wavelengths up to 1.1 μm. Novel nonlinear optical materials, glassy graphene oxide (GO)-based silico-phosphate composites, were prepared, for the first time to our knowledge, by a convenient and low cost sol-gel method, as described in the paper, using tetraethyl orthosilicate (TEOS), H3PO4 and GO/reduced GO (rGO) as precursors. The characterisation of the GO/rGO silico-phosphate composite films was performed by spectroscopy (Fourier-transform infrared (FTIR), Ultraviolet–Visible-Near Infrared (UV-VIS-NIR) and Raman) and microscopy (atomic force microscopy (AFM) and scanning electron microscopy (SEM)) techniques. H3PO4 was found to reduce the rGO dispersed in the precursor’s solution with the formation of vertically agglomerated rGO sheets, uniformly distributed on the substrate surface. The capability of these novel graphene oxide-based materials for the optical limiting of femtosecond laser pulses at 1550 nm wavelength was demonstrated by intensity-scan experiments. The GO or rGO presence in the film, their concentrations, the composite films glassy matrix, and the film substrate influence the optical limiting performance of these novel materials and are discussed accordingly.
Synthesis of Green-Emitting Gd2O2S:Pr3+ Phosphor Nanoparticles and Fabrication of Translucent Gd2O2S:Pr3+ Scintillation Ceramics
Authors: Sun Zhigang , Lu Bin , Ren Guiping , Chen Hongbing
Published: August 2020

A translucent Gd2O2S:Pr ceramic scintillator with an in-line transmittance of ~31% at 512 nm was successfully fabricated by argon-controlled sintering. The starting precipitation precursor was obtained by a chemical precipitation route at 80 °C using ammonia solution as the precipitate, followed by reduction at 1000 °C under flowing hydrogen to produce a sphere-like Gd2O2S:Pr powder with an average particle size of ~95 nm. The Gd2O2S:Pr phosphor particle exhibits the characteristic green emission from 3P0,1→3H4 transitions of Pr3+ at 512 nm upon UV excitation into a broad excitation band at 285–335 nm arising from 4f2→4f5d transition of Pr3+. Increasing Pr3+ concentrations induce two redshifts for the two band centers of 4f2→4f5d transition and lattice absorption on photoluminescence excitation spectra. The optimum concentration of Pr3+ is 0.5 at.%, and the luminescence quenching type is dominated by exchange interaction. The X-ray excited luminescence spectrum of the Gd2O2S:Pr ceramic is similar to the photoluminescence behavior of its particle. The phosphor powder and the ceramic scintillator have similar lifetimes of 2.93–2.99 μs, while the bulk material has rather higher external quantum efficiency (~37.8%) than the powder form (~27.2%).
Association between Unhealthy Dietary Habits and Proteinuria Onset in a Japanese General Population: A Retrospective Cohort Study
Authors: Tokumaru Toshiaki , Toyama Tadashi , Hara Akinori , Kitagawa Kiyoki , Yamamura Yuta , Nakagawa Shiori , Oshima Megumi , Miyagawa Taro , Sato Koichi , Ogura Hisayuki , Kitajima Shinji , Iwata Yasunori , Sakai Norihiko , Shimizu Miho , Furuichi Kengo , Hashiba Atsushi , Wada Takashi
Published: August 2020

The relationship between dietary habits and development of chronic kidney disease (CKD) is unclear. This retrospective cohort study was conducted to examine the association between unhealthy dietary habits and proteinuria onset, a key prognostic factor of CKD, among a Japanese general population aged ≥40 years. The risks of proteinuria onset were estimated based on the status of baseline unhealthy dietary habits (quick eating, late dinner, late evening snack, and skipping breakfast) compared with the status without these habits. A total of 26,764 subjects were included, with a mean follow-up period of 3.4 years. The most frequent unhealthy dietary habit was quick eating (29%), followed by late dinner (19%), late evening snack (16%), and skipping breakfast (9%). During the follow-up period, 10.6% of participants developed proteinuria. Late dinner and skipping breakfast showed an increased adjusted risk of proteinuria onset (hazard ratio (HR) 1.12, 95% confidence interval (CI) 1.02 to 1.22, and HR 1.15, 95% CI 1.01 to 1.31, respectively). Unhealthy dietary habits were not associated with changes in body mass index or waist-to-height ratio during the follow-up period. Our results suggest that late dinner and skipping breakfast are associated with higher risks for proteinuria onset.