bluuebunny/crossref_metadata_2025 huggingface dataset:
Facile Synthesis of Di-Mannitol Adipate Ester-Based Zinc Metal Alkoxide as a Bi-Functional Additive for Poly(Vinyl Chloride)
Authors: Li Yuepeng , Li Degang , Han Wenyuan , Zhang Manqi , Ai Bing , Zhang Lipeng , Sun Hongqi , Cui Zhen
Published: May 2019

A new di-mannitol adipate ester-based zinc metal alkoxide (DMAE-Zn) was synthesized as a bi-functional poly(vinyl chloride) (PVC) thermal stabilizer for the first time. The materials were characterized with Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Characterization results confirmed the formation of Zn–O bonds in DMAE-Zn, and confirmed that DMAE-Zn had a high decomposition temperature and a low melting point. The thermal stability of DMAE-Zn on PVC also was tested by a conductivity test, a thermal aging test, and a UV-visible spectroscopy (UV-VIS) test. PVC stabilized by DMAE-Zn had a good initial color and excellent long-term stability. UV-VIS also showed that the conjugated structure in PVC stabilized by DMAE-Zn was almost all of the triene, suggesting that the addition of DMAE-Zn would suppress the formation of conjugated structures above tetraene. The dynamic processing performance of PVC samples tested by torque rheometer indicated that, having a good compatibility with PVC chains in the amorphous regions, DMAE-Zn contributed a good plasticizing effect to PVC. DMAE-Zn thus effectively demonstrates bi-functional roles, e.g., thermal stabilizers and plasticizers to PVC. Furthermore, FT-IR, a HCl absorption capacity test, and a complex ZnCl2 test were also used to verify the thermal stability mechanism of DMAE-Zn for PVC.
Stabilization of Pickering Emulsions by Hairy Nanoparticles Bearing Polyanions
Authors: Zhang Ying , Chen Kaimin , Cao Lan , Li Kai , Wang Qiaoling , Fu Enyu , Guo Xuhong
Published: May 2019

Pickering emulsions are increasingly applied in drug delivery, oil–water separation, composite materials preparation, and other fields. However, systematic studies on the stabilization of Pickering emulsions to satisfy the growing application demands in multiple fields with long-term conservation are rare. Compared to conventional solid nanoparticles, polyanion-modified hairy nanoparticles are more stable in practical environments and are investigated in this study. Poly (sodium p-styrenesulfonate) was grafted to a polystyrene (PS) core via a photoemulsion polymerization. A hairy nanoparticle bearing polyanions called poly (sodium p-styrenesulfonate) brush (PS@PSS) was synthesized. The size and uniformity of the Pickering emulsions stabilized by PS@PSS were investigated via a polarizing microscope. The stability of Pickering emulsions were optimized by adjusting critical factors like ultrasonic power and time, standing time, oil phases, salt concentration, and water:oil ratio. Results indicated that the Pickering emulsions could be stabilized by PS@PSS nanoparticles, which showed remarkable and adjustable partial wetting properties. It was found that the optimized conditions were ultrasonic power of 150 W, ultrasonic time of 3 min, salt concentration of 0.1 mM, oil phase of hexadecane, and water:oil ratio of 1:1. The formation and stability of Pickering emulsion are closely related to the hairy poly (sodium p-styrenesulfonate) brush layer on the nanoparticle surface.
Effects of Gas Adsorption on the Mechanical Properties of Amorphous Polymer
Authors: Kim Shin Won , Sohn Joo Seong , Kim Hyun Keun , Ryu Youngjae , Cha Sung Woon
Published: May 2019

This study investigates the properties of a polymer–gas mixture formed through diffusion, based on the changes in the partial pressure and observed changes in the impact and tensile strengths owing to the gas dissolution. The high-pressure gas dissolves into a solid-state polymer through diffusion based on the difference in the partial pressure. This dissolved gas is present in the amorphous region within the polymeric material temporarily, which results in the polymer exhibiting different mechanical properties, while the gas remains dissolved in the polymer. In this study, the mechanical properties of amorphous polyethylene terephthalate (APET) specimens prepared by dissolving CO2 using a high-pressure vessel were investigated, and the resulting impact and tensile strengths were measured. These experiments showed that the increase in sorption rate of CO2 caused an increase in the impact strength. At 2.9% CO2 absorption, the impact strength of APET increased 956% compared to that of the reference specimen. Furthermore, the tensile strength decreased by up to 71.7% at 5.48% CO2 sorption; the stress–strain curves varied with the gas sorption rate. This phenomenon can be associated with the change in the volume caused by CO2 dissolution. When the APET absorbed more than 2.0% CO2 gas, sample volume increased. A decrease in the network density can occur when the volume is increased while maintaining constant mass. The CO2 gas in the polymer acted as a cushion in impact tests which have sorption rates above 2%. In addition to the reduction in the network density in the polymer chain, Van Der Waals forces are decreased causing a decrease in tensile strength only while CO2 is present in the APET. These observations only occur prior to CO2 desorption from the polymer.
Amphiphilic Block Copolymer Poly (Acrylic Acid)-B-Polycaprolactone as a Novel pH-sensitive Nanocarrier for Anti-Cancer Drugs Delivery: In-vitro and In-vivo Evaluation
Authors: Liu Huanhuan , Chen Hong , Cao Fuhu , Peng Daiyin , Chen Weidong , Zhang Chuanling
Published: May 2019

Gambogenic acid (GNA) has been demonstrated with outstanding antitumor activity as a potential antitumor drug in recent years. However, the low solubility and deficient bioavailability of GNA seriously hinder its practical application in the clinic area. In this study, a novel amphiphilic block copolymer, poly (acrylic acid)-b-polycaprolactone (PAA-b-PCL) is prepared and assembled into pH-responsive polymeric micelles (PMs) as one mold of drug delivery system (DDS) with unique properties. Relevant investigation on PMs exhibits excellent carrying potential and pH-dependent release performance for GNA. The drug loading capacity (DLC) and drug loading efficiency (DLE) for GNA-loaded PMs can be achieved as high as 15.20 ± 0.07% and 83.67 ± 0.49%, respectively. The in vitro experiments indicate that the GNA releasing time, cytotoxicity, and cellular uptake are significantly enhanced. Especially, the peak concentration (Cmax) and area under the curve (AUC) are promoted sharply in the GNA-loaded PMs concentration-time curve. This study not only provides a novel way to widen the application of anticancer GNA in the future, but also extends the potential of stimuli-responsive copolymers to biomedical applications.
Cost-Effective PEDOT:PSS Temperature Sensors Inkjetted on a Bendable Substrate by a Consumer Printer
Authors: Rivadeneyra Almudena , Bobinger Marco , Albrecht Andreas , Becherer Markus , Lugli Paolo , Falco Aniello , Salmerón Jose F.
Published: May 2019

In this work, we report on a fabrication protocol to produce fully inkjet-printed temperature sensors on a bendable polyethylene terephthalate (PET) substrate. The sensing layer is made of polymer-based Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) ink that is electrically contacted by an underlying interdigitated electrode (IDE) structure based on a silver nanoparticle (AgNP) ink. Both inks are available commercially, and no further ink processing is needed to print them using a cost-effective consumer printer with standard cartridges. The fabricated sensor modules are tested for different IDE dimensions and post-deposition treatments of the AgNP film for their response to a temperature range of 20 to 70 °C and moisture range of 20 to 90% RH (relative humidity). Attributed to the higher initial resistance, sensor modules with a larger electrode spacing of 200 µm show a higher thermal sensitivity that is increased by a factor of 1.8 to 2.2 when compared to sensor modules with a 150 µm-spacing. In all cases, the sensors exhibit high linearity towards temperature and a response comparable to state of the art.
Selenol-Based Nucleophilic Reaction for the Preparation of Reactive Oxygen Species-Responsive Amphiphilic Diblock Copolymers
Authors: An Xiaowei , Lu Weihong , Zhu Jian , Pan Xiangqiang , Zhu Xiulin
Published: May 2019

Selenide-containing amphiphilic copolymers have shown significant potential for application in drug release systems. Herein, we present a methodology for the design of a reactive oxygen species-responsive amphiphilic diblock selenide-labeled copolymer. This copolymer with controlled molecular weight and narrow molecular weight distribution was prepared by sequential organoselenium-mediated reversible addition fragmentation chain transfer (Se-RAFT) polymerization and selenol-based nucleophilic reaction. Nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization time-to-flight (MALDI-TOF) techniques were used to characterize its structure. Its corresponding nanomicelles successfully formed through self-assembly from the copolymer itself. Such nanomicelles could rapidly disassemble under oxidative conditions due to the fragmentation of the Se–C bond. Therefore, this type of nanomicelle based on selenide-labeled amphiphilic copolymers potentially provides a new platform for drug delivery.
Cobalt Nanoparticles Embedded into N-Doped Carbon from Metal Organic Frameworks as Highly Active Electrocatalyst for Oxygen Evolution Reaction
Authors: Lu Jitao , Zeng Yue , Ma Xiaoxue , Wang Huiqin , Gao Linna , Zhong Hua , Meng Qingguo
Published: May 2019

Cystosepiment-like cobalt nanoparticles@N-doped carbon composite named Co-NPs@NC with highly efficient electrocatalytic performance for oxygen evolution reaction was prepared from carbonization of N-doped Co-MOFs. The optimized Co-NPs@NC-600 shows overpotentials of 315 mV to afford a current density of 10 mA·cm−2. Meanwhile, the electrocatalys presents excellent long-term durability. The outstanding electrocatalytic performance can be attributed to the unique cystosepiment-like architecture with high specific surface area (214 m2/g), high conductivity of N-doped carbon and well-distributed active sites.
Preparation, Characterization and In Vitro Biological Evaluation of a Novel Pearl Powder/Poly-Amino Acid Composite as a Potential Substitute for Bone Repair and Reconstruction
Authors: Wu Yanan , Ding Zhengwen , Ren Haohao , Ji Mizhi , Yan Yonggang
Published: May 2019

Many studies about fabricating organic-inorganic composite materials have been carried out in order to mimic the natural structure of bone. Pearl, which has a special block-and-mortar hierarchical structure, is a superior bone repair material with high osteogenic activity, but it shows few applications in the clinical bone repair and reconstruction because of its brittle and uneasily shaped properties. In this work, pearl powder (P)/poly (amino acid) (PAA) composites were successfully prepared by a method of in situ melting polycondensation to combine the high osteogenic activity of the pearl and the pliability of the PAA. The mechanical properties, in vitro bioactivity and biocompatibility as well as osteogenic activity of the composites were investigated. The results showed that P/PAA composites have both good mechanical properties and bioactivity. The compressive strength, bending strength and tensile strength of the composites reached a maximum of 161 MPa, 50 MPa and 42 MPa, respectively; in addition, apatite particles successfully deposited on the composites surface after immersion in simulated body fluid (SBF) for 7 days indicated that P/PAA composites showed an enhanced mineralization capacity and bioactivity due to incorporation of pearl powder and PAA. The cell culture results revealed that higher cell proliferation and better adhesion morphology of mouse bone marrow mesenchymal stem cells (MSCs) appeared on the composite surface. Moreover, cells growing on the surface of the composites exhibited higher alkaline phosphatase (ALP) activity, more calcium nodule-formation, and higher expression levels of osteogenic differentiation-related genes (COL 1, RunX2, OCN, and OPN) than cells grown on PAA surface. The P/PAA composites exhibited both superior mechanical properties to the pearl powder, higher bioactivity and osteogenic capability compared with those of PAA.
Development of an Advanced Dynamic Microindentation System to Determine Local Viscoelastic Properties of Polymers
Authors: Ramakers-van Dorp Esther , Haenel Thomas , Ciongwa Dominik , Möginger Bernhard , Hausnerova Berenika
Published: May 2019

This study presents a microindentation system which allows spatially resolved local as well as bulk viscoelastic material information to be obtained within one instrument. The microindentation method was merged with dynamic mechanical analysis (DMA) for a tungsten cone indenter. Three tungsten cone indenters were investigated: tungsten electrode, tungsten electrode + 2% lanthanum, and tungsten electrode + rare earth elements. Only the tungsten electrode + 2% lanthanum indenter showed the sinusoidal response, and its geometry remained unaffected by the repeated indentations. Complex moduli obtained from dynamic microindentation for high-density polyethylene, polybutylene terephthalate, polycarbonate, and thermoplastic polyurethane are in agreement with the literature. Additionally, by implementing a specially developed x-y-stage, this study showed that dynamic microindentation with a tungsten cone indenter was an adequate method to determine spatially resolved local viscoelastic surface properties.
Effect of Bifunctional Montmorillonite on the Thermal and Tribological Properties of Polystyrene/Montmorillonite Nanocomposites
Authors: Yu Chengcheng , Ke Yangchuan , Hu Xu , Zhao Yi , Deng Qingchun , Lu Shichao
Published: May 2019

In this work, the effect of doubly functionalized montmorillonite (MMT) on the structure, morphology, thermal, and tribological characteristics of the resulting polystyrene (PS) nanocomposites was investigated. The modification of the MMT was performed using a cationic surfactant and an anionic surfactant or a silane coupling agent to increase the compatibility with PS matrix. The polystyrene/organo-montmorillonite (PS/OMMT) nanocomposite particles were prepared by soap-free emulsion polymerization. The OMMT was studied using Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The structural and morphological changes of PS/OMMT nanocomposites were further characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal stability of all the PS/OMMT nanocomposites was higher than that of the pure PS. The anti-wear properties of the polyalphaolefin (PAO) were significantly improved due to the introduction of the PS/OMMT nanocomposite particles. The nanocomposites prepared by a cationic surfactant and a silane coupling agent exhibited the best thermal stability and tribological performance. Our results provide the valuable insights needed to guide the design of lubrication and friction reducing materials.
Lignin Transformation of One-Year-Old Plants During Anaerobic Digestion (AD)
Authors: Waliszewska Hanna , Zborowska Magdalena , Stachowiak-Wencek Agata , Waliszewska Bogusława , Czekała Wojciech
Published: May 2019

The aim of the research is to identify the changes which occur in lignin from miscanthus and sorghum, one of the main biomass components, as a result of an anaerobic digestion (AD) process. The percentage content and structure of lignin before and after the fermentation process were analysed using biomass harvested in two growing periods—before and after vegetation. It was shown that plants at different developmental stages differ in lignin content. During plant growth, the lignin structure also changes—the syringyl-to-guaiacyl ratio (S/G) increases, whereas the aliphatic and aromatic structure ratio (Al/Ar) decreases. The AD process leads to an increase in percentage lignin content in cell walls, and the increase is higher for plants harvested during vegetation. It has been shown in studies that the methane fermentation of miscanthus and sorghum produces waste containing a large amount of lignin, the structure of which is altered relative to native lignin. The quantity and the new, simplified structure of lignin create new possibilities for using this aromatic polymer.
Unprecedentedly High Activity and/or High Regio-/Stereoselectivity of Fluorenyl-Based CGC Allyl-Type η3:η1-tert-Butyl(dimethylfluorenylsilyl)amido Ligated Rare Earth Metal Monoalkyl Complexes in Olefin Polymerization
Authors: Guo Ge , Wu Xiaolu , Yan Xiangqian , Yan Li , Li Xiaofang , Zhang Shaowen , Qiu Nannan
Published: May 2019

A series of fluorenyl-based constrained-geometry-configuration (CGC) allyl-type rare earth metal monoalkyl complexes bearing the divalent anionic η3:η1-tert-butyl(dimethylfluorenylsilyl)amido (η3:η1-FluSiMe2NtBu) ligand (η3:η1-FluSiMe2NtBu)Ln(CH2SiMe3)(THF)2 (1–3) have been synthesized via the alkane elimination reaction between the FluHSiMe2NHtBu ligand and rare earth metal tri(trimethylsilylmethyl) complexes Ln(CH2SiMe3)3(THF)n. Their structures are characterized by means of NMR spectrum, elemental analyses, and X-ray diffraction. These complexes 1–3 are isostructural and isomorphous, and each of them adopts a distorted-trigonal-bipyramidal configuration containing one η3:η1-FluSiMe2NtBu ligand, one CH2SiMe3 ligand, and two THF molecules. Unlike traditional CGC allyl-type rare earth metal complexes showing no or low activity and regio-/stereoselectivity in styrene or MMA polymerization, these complexes 1–3 exhibit high catalytic activities and/or high regio-/stereoselectivities in the cis-1,4-polymerization of isoprene and myrcene or in the syndiotactic polymerization of styrene under the aid of different activators (borate or borane) and AlR3. The in situ 1H NMR spectra suggest that the exchanges of chelating ligands such as alkyl groups and divalent anionic η3:η1-FluSiMe2NtBu ligands between rare earth metal centers and Al centers result in the formation of a heterobimetallic tetraalkylaluminate complex R2Al(μ-R)2Ln(R)(μ-R)2AlR2, which is activated by activators to form a divalent cationic species [Ln(μ-R)2AlR2]2+ as a catalytically active species in the coordination–insertion polymerization of olefins.
Thermal Analysis of Crystallization and Phase Transition in Novel Polyethylene Glycol Grafted Butene-1 Copolymers
Authors: An Chuanbin , Li Yulian , Lou Yahui , Song Dongpo , Wang Bin , Pan Li , Ma Zhe , Li Yuesheng
Published: May 2019

Copolymerization is an effective strategy to regulate the molecular structure and tune crystalline structures. In this work, novel butene-1 copolymers with different polyethylene glycol (PEG) grafts (number-average molecular weight Mn = 750, 2000, and 4000 g/mol) were synthesized, for the first time introducing long-chain grafts to the polybutene-1 main chain. For these PEG-grafted copolymers, crystallization, melting, and phase transition behaviors were explored using differential scanning calorimetry. With respect to the linear homopolymer, the incorporation of a trimethylsilyl group decreases the cooling crystallization temperature (Tc), whereas the presence of the long PEG grafts unexpectedly elevates Tc. For isothermal crystallization, a critical temperature was found at 70 °C, below which all polyethylene glycol-grafted butene-1 (PB-PEG) copolymers have faster crystallization kinetics than polybutene-1 (PB). The subsequent melting process shows that for the identical crystallization temperature, generated PB-PEG crystallites always have lower melting temperatures than that of PB. Moreover, the II-I phase transition behavior of copolymers is also dependent on the length of PEG grafts. When form II, obtained from isothermal crystallization at 60 °C, was annealed at 25 °C, PB-PEG-750, with the shortest PEG grafts of Mn = 750 g/mol, could have the faster transition rate than PB. However, PB-PEG-750 exhibits a negative correlation between transition rate and crystallization temperature. Differently, in PB-PEG copolymers with PEG grafts Mn = 2000 and 4000 g/mol, transition rates rise with elevating crystallization temperature, which is similar with homopolymer PB. Therefore, the grafting of the PEG side chain provides the available method to tune phase transition without sacrificing crystallization capability in butene-1 copolymers.
Effects of Diisocyanate Structure and Disulfide Chain Extender on Hard Segmental Packing and Self-Healing Property of Polyurea Elastomers
Authors: Li Ting , Zheng Tianze , Han Jiarui , Liu Zhanli , Guo Zhao-Xia , Zhuang Zhuo , Xu Jun , Guo Bao-Hua
Published: May 2019

Four linear polyurea elastomers synthesized from two different diisocyanates, two different chain extenders and a common aliphatic amine-terminated polyether were used as models to investigate the effects of both diisocyanate structure and aromatic disulfide chain extender on hard segmental packing and self-healing ability. Both direct investigation on hard segments and indirect investigation on chain mobility and soft segmental dynamics were carried out to compare the levels of hard segmental packing, leading to agreed conclusions that correlated well with the self-healing abilities of the polyureas. Both diisocyanate structure and disulfide bonds had significant effects on hard segmental packing and self-healing property. Diisocyanate structure had more pronounced effect than disulfide bonds. Bulky alicyclic isophorone diisocyanate (IPDI) resulted in looser hard segmental packing than linear aliphatic hexamethylene diisocyanate (HDI), whereas a disulfide chain extender also promoted self-healing ability through loosening of hard segmental packing compared to its C-C counterpart. The polyurea synthesized from IPDI and the disulfide chain extender exhibited the best self-healing ability among the four polyureas because it had the highest chain mobility ascribed to the loosest hard segmental packing. Therefore, a combination of bulky alicyclic diisocyanate and disulfide chain extender is recommended for the design of self-healing polyurea elastomers.
Educating Desire: Conversion and Ascent in Dante’s Purgatorio
Authors: Camacho Paul A.
Published: May 2019

In Cantos 17 and 18 of the Purgatorio, Dante’s Virgil lays out a theory of sin, freedom, and moral motivation based on a philosophical anthropology of loving-desire. As the commentary tradition has long recognized, because Dante placed Virgil’s discourse on love at the heart of the Commedia, the poet invites his readers to use love as a hermeneutic key to the text as a whole. When we contextualize Virgil’s discourse within the broader intention of the poem—to move its readers from disordered love to an ordered love of ultimate things—then we find in these central cantos not just a key to the structure and movement of the poem, but also a key to understanding Dante’s pedagogical aim. With his Commedia, Dante invites us to perform the interior transformation which the poem dramatizes in verse and symbol. He does so by awakening in his readers not only a desire for the beauty of his poetic creation, but also a desire for the beauty of the love described therein. In this way, the poem presents a pedagogy of love, in which the reader participates in the very experience of desire and delight enacted in the text. In this article, I offer an analysis of Virgil’s discourse on love in the Purgatorio, arguing for an explicit and necessary connection between loving-desire and true education. I demonstrate that what informs Dante’s pedagogy of love is the notion of love as ascent, a notion we find articulated especially in the Christian Platonism of Augustine. Finally, I conclude by offering a number of figures, passages, and themes from across the Commedia that provide fruitful material for teachers engaged in the task of educating desire.
Shamanic Sports: Buryat Wrestling, Archery, and Horse Racing
Authors: Krist Stefan
Published: May 2019

This paper presents the religious aspects of the historical and present forms of the traditional sports competitions of the Buryats—a Mongolian ethnic group settled in Southern Siberia, Northern Mongolia, and North-Eastern China. Both historically and in our time, their traditional sports have been closely linked to shamanic rituals. This paper provides insights into the functions of these sports competitions for Buryat shamanic rituals—why they have been, and still are, an inevitable part of these rituals. They are believed to play an important role in these rituals, which aim to trick and/or please the Buryats’ spirits and gods in order to get from them what is needed for survival. The major historical changes in the Buryats’ constructions of their relationship to their imagined spiritual entities and the corresponding changes in their sports competitions are described. The effects of both economic changes—from predominantly hunting to primarily livestock breeding—and of changes in religious beliefs and world views—from shamanism to Buddhism and from Soviet Communist ersatz religion to the post-Soviet revival of shamanism and Buddhism—are described. Special attention is given to the recent revival of these sports’ prominent role for Buddhist and shamanist rituals.
‘Examining Religion’ through Generations of Jain Audiences: The Circulation of the Dharmaparīkṣā
Authors: De Jonckheere Heleen
Published: May 2019

Indian literary traditions, both religious and non-religious, have dealt with literature in a fluid way, repeating and reusing narrative motifs, stories and characters over and over again. In recognition of this, the current paper will focus on one particular textual tradition within Jainism of works titled Dharmaparīkṣā and will trace its circulation. This didactic narrative, designed to convince a Jain audience of the correctness of Jainism over other traditions, was first composed in the tenth century in Apabhraṃśa and is best known in its eleventh-century Sanskrit version by the Digambara author Amitagati. Tracing it from a tenth-century context into modernity, across both classical and vernacular languages, will demonstrate the popularity of this narrative genre within Jain circles. The paper will focus on the materiality of manuscripts, looking at language and form, place of preservation, affiliation of the authors and/or scribe, and patronage. Next to highlighting a previously underestimated category of texts, such a historical overview of a particular literary circulation will prove illuminating on broader levels: it will show networks of transmission within the Jain community, illustrate different types of mediation of one literary tradition, and overall, enrich our knowledge of Jain literary culture.
Masterpieces, Altarpieces, and Devotional Prints: Close and Distant Encounters with Michelangelo’s Vatican Pietà
Authors: Jurkowlaniec Grażyna
Published: May 2019

Focussing on the response to the Vatican Pietà and perversely using as a point of departure a 1549 remark on Michelangelo as an ‘inventor of filth,’ this article aims to present Michelangelo as an involuntary inventor of devotional images. The article explores hitherto unconsidered aspects of the reception of the Vatican Pietà from the mid-sixteenth into the early seventeenth century. The material includes mediocre anonymous woodcuts, and elaborate engravings and etchings by renowned masters: Giulio Bonasone, Cornelis Cort, Jacques Callot and Lucas Kilian. A complex chain of relationships is traced among various works, some referring directly to the Vatican Pietà, some indirectly, neither designed nor perceived as its reproductions, but conceived as illustrations of the Syriac translation of the New Testament, of Latin and German editions of Peter Canisius’s Little catechism, of the frontispiece of the Règlement et établissement de la Compagnie des Pénitents blancs de la Ville de Nancy—but above all, widespread as single-leaf popular devotional images.
Islamic Friday Sermon in Italy: Leaders, Adaptations, and Perspectives
Authors: Sbai Youssef
Published: May 2019

The focus of this article is to spotlight the ritual frame of the canonical Friday prayer that is organized weekly around midday in places of Islamic worship in Italy. I verify how the Muslim communities in Italy, as a “cognitive minority”, use different strategies related to the performance of the Friday prayer ritual, and I analyze its continuous reframing. During the preliminary investigation I selected seventeen places of worship located in major cities and provincial towns located in the North, Central and South of Italy including Sicily. I have only considered spaces run by Sunni Arabs because they are the majority of Muslims in Italy. In these places I performed the participant observation from October 2016 to July 2017 collecting empirical data and more than a hundred sermons that I analyzed later. I also relied on interviews with preachers and people in charge of these places.
Coming Home (Ghar Wapsi) and Going Away: Politics and the Mass Conversion Controversy in India
Authors: Rajeshwar Yashasvini , Amore Roy C.
Published: May 2019

This article addresses two recent socio-religious trends in India: mass conversions to Hinduism (Ghar Wapsi) and mass conversions from Hinduism. Despite officially being a secular nation, organizations allied with the ruling Bharatiya Janata Party (BJP) are actively promoting mass conversions to Hinduism. Other religions organize mass conversions, usually of Dalits, away from Hinduism and its legacy of caste discrimination. While several states have controversial laws placing restrictions on mass conversions from Hinduism, mass conversions to Hinduism are often seen as being promoted rather than restricted.
A Context-Grounded Approach to Religious Freedom: The Case of Orthodoxy in the Moldovan Republic
Authors: Carnevale Davide N.
Published: May 2019

This paper explores the relationship between human rights and social analysis within the main historical and theoretical perspectives adopted by social sciences. In particular, religious freedom will be analysed as one of the central issues in the recent engagement of the social sciences with human rights. After examining current narratives and mainstream approaches of the social sciences towards the right to religious freedom, this article will then underline the importance of a social epistemology which goes beyond a normative and legal perspective, bridging the gap between the framework of human rights and the social roles of religion in context. Within this framework, religious freedom represents a social construct, whose perception, definition and implementation dynamically evolves according to its influence, at different levels, in the lived dimension of social relations. The second part of the article proposes a context-grounded analysis of religious freedom in the Republic of Moldova. This case study is characterised by the impressive growth of Orthodoxy after the demise of the Soviet Union and by a complex and contradictory political approach towards religious freedom, both as a legal standard and as a concept. Emerging through the analysis of local political narratives and some preliminary ethnographical observations, the social importance of religion will be investigated both as a governmental instrument and as an embodied means of dealing with widespread socio-economic insecurity, creating tensions between religious rootedness and religious freedom. The local debate on religious freedom will then be related to the influence of geopolitical borders, the topic of traditional identity and the religious form of adaptation to the ineffectiveness of the new secular local policies, with orthodox institutions and parishes having new socio-political roles at both a global and local scale.
Mystery Manifested: Toward a Phenomenology of the Eucharist in Its Liturgical Context
Authors: Gschwandtner Christina M.
Published: May 2019

This article explores three contemporary phenomenological analyses of the Eucharist by the French phenomenologists Jean-Luc Marion, Jean-Yves Lacoste, and Emmanuel Falque, arguing that their descriptions are too excessive and individual, failing to take into account the broader liturgical context for eucharistic experience. The second part of the discussion seeks to develop an alternate phenomenological account of eucharistic experience that takes Eucharist seriously as a corporeal and communal phenomenon that is encountered within a liturgical horizon and which requires a liturgical intentionality to be prepared for and directed toward it.
Delayed Onset of Dural Arteriovenous Fistula Following Trauma
Authors: Richardson William , Satarasinghe Praveen , Koltz Michael T.
Published: May 2019

Dural Arteriovenous Fistulas (dAVF) are pathological shunts that are often idiopathic in presentation. However, it is reported that many patients presenting with dAVF have past medical histories notable for surgeries, hypercoagulation disorders, infections, and trauma. In trauma-linked dAVF, presentation generally occurs within 48 h post-incident. In the present case, the authors discuss the delayed onset of a Borden type II dAVF in a patient 12 hospital days post-trauma, as well as the course of treatment. This unique case provides a compelling demonstration for providers to be aware of the development of dAVF, even after the typical 48-hour post-trauma window. By being aware of the possibility of delayed dAVF presentation, delayed diagnosis or misdiagnosis can be avoided and emergent action can be taken.
Classifying Inundation in a Tropical Wetlands Complex with GNSS-R
Authors: Rodriguez-Alvarez Nereida , Podest Erika , Jensen Katherine , McDonald Kyle C.
Published: May 2019

The use of global navigation satellite system reflectometry (GNSS-R) measurements for classification of inundated wetlands is presented. With the launch of NASA’s Cyclone Global Navigation Satellite System (CYGNSS) mission, space-borne GNSS-R measurements have become available over ocean and land. CYGNSS covers latitudes between ±38°, providing measurements over tropical ecosystems and benefiting new studies of wetland inundation dynamics. The GNSS-R signal over inundated wetlands is driven mainly by coherent scattering associated with the presence of surface water, producing strong forward scattering and a distinctive bistatic scattering signature. This paper presents a methodology used to classify inundation in tropical wetlands using observables derived from GNSS-R measurements and ancillary data. The methodology employs a multiple decision tree randomized (MDTR) algorithm for classification and wetland inundation maps derived from the phased-array L-band synthetic aperture radar (PALSAR-2) as reference for training and validation. The development of an innovative GNSS-R wetland classification methodology is aimed to advance mapping of global wetland distribution and dynamics, which is critical for improved estimates of natural methane production. The results obtained in this manuscript demonstrate the ability of GNSS-R signals to detect inundation under dense vegetation over the Pacaya-Samiria Natural Reserve, a tropical wetland complex located in the Peruvian Amazon. Classification results report an accuracy of 69% for regions of inundated vegetation, 87% for open water regions, and 99% for non-inundated areas. Misclassification of inundated vegetation, primarily as non-inundated area, is likely related to the combination of two factors: partial inundation within the GNSS-R scattering area, and signal attenuation from dense overstory vegetation, resulting in a low signal.
Retrieving Phytoplankton Size Class from the Absorption Coefficient and Chlorophyll A Concentration Based on Support Vector Machine
Authors: Deng Lin , Zhou Wen , Cao Wenxi , Zheng Wendi , Wang Guifen , Xu Zhantang , Li Cai , Yang Yuezhong , Hu Shuibo , Zhao Wenjing
Published: May 2019

The phytoplankton size class (PSC) plays an important role in biogeochemical processes in the ocean. In this study, a regional model of PSCs is proposed to retrieve vertical PSCs from the total minus water absorption coefficient (at-w(λ)) and Chlorophyll a concentration (Chla). The PSC model is developed by first reconstructing phytoplankton absorption and Chla from at-w(λ), and then extracting PSC from them using the support vector machine (SVM). In situ bio-optical data collected in the South China Sea from 2006 to 2013 were used to train the SVM. The proposed PSC model was subsequently validated using an independent PSC dataset from the Northeast South China Sea Cruise in 2015. The results indicate that the PSC model performed better than the three components model, with a value of r2 between 0.35 and 0.66, and the absolute percentage difference between 56% and 181%. On the whole, our PSC model shows a remarkable utility in terms of inferring vertical PSCs from the South China Sea.
Fine Land-Cover Mapping in China Using Landsat Datacube and an Operational SPECLib-Based Approach
Authors: Zhang Xiao , Liu Liangyun , Chen Xidong , Xie Shuai , Gao Yuan
Published: May 2019

Fine resolution land cover information is a vital foundation of Earth science. In this paper, a novel SPECLib-based operational method is presented for the classification of multi-temporal Landsat imagery using reflectance spectra from the spatial-temporal spectral library (SPECLib) for 30 m land-cover mapping for the whole of China. Firstly, using the European Space Agency (ESA) Climate Change Initiative Global Land Cover (CCI_LC) product and the MODIS Version 6 Nadir bidirectional reflectance distribution function adjusted reflectance (NBAR) product (MCD43A4), a global SPECLib with a spatial resolution of 158.85 km (equivalent to 1.43° at the equator) and a temporal resolution of eight days was developed in the sinusoidal projection. Then, the Landsat datacube covering the whole of China was developed using all available observations of Landsat OLI imagery in 2015. Thirdly, the multi-temporal random forest method based on SPECLib was presented to produce an annual land-cover map with 22 land-cover types using the Landsat datacube. Finally, the annual China land-cover map was validated by two different validation systems using approximately 11,000 interpretation points. The mapping results achieved the overall accuracy of 71.3% and 80.7% and the kappa coefficient of 0.664 and 0.757 for the level-2 validation system (19 land-cover types) and the level-1 validation system (nine land-cover types), respectively. Therefore, the case study in China indicates that the proposed SPECLib method is an operational and accurate method for regional/global fine land-cover mapping at a spatial resolution of 30 m.
Real-Time Uncertainty Specification of All Sky Imager Derived Irradiance Nowcasts
Authors: Nouri Bijan , Wilbert Stefan , Kuhn Pascal , Hanrieder Natalie , Schroedter-Homscheidt Marion , Kazantzidis Andreas , Zarzalejo Luis , Blanc Philippe , Kumar Sharad , Goswami Neeraj , Shankar Ravi , Affolter Roman , Pitz-Paal Robert
Published: May 2019

The incoming downward shortwave solar irradiance is harvested to an increasing extent by solar power plants. However, the variable nature of this energy source poses an operational challenge for solar power plants and electrical grids. Intra hour solar irradiance nowcasts with a high temporal and spatial resolution could be used to tackle this challenge. All sky imager (ASI) based nowcasting systems fulfill the requirements in terms of temporal and spatial resolution. However, ASI nowcasts can only be used if the required accuracies for applications in solar power plants and electrical grids are fulfilled. Scalar error metrics, such as mean absolute deviation, root mean square deviation, and skill score are commonly used to estimate the accuracy of nowcasting systems. However, these overall error metrics represented by a single number per metric are neither suitable to determine the real time accuracy of a nowcasting system in the actual weather situation, nor suitable to describe any spatially resolved nowcast accuracy. The performance of ASI-based nowcasting systems is strongly related to the prevailing weather conditions. Depending on weather conditions, large discrepancies between the overall and current system uncertainties are conceivable. Furthermore, the nowcast accuracy varies strongly within the irradiance map as higher errors may occur at transient zones close to cloud shadow edges. In this paper, we present a novel approach for the spatially resolved real-time uncertainty specification of ASI-based nowcasting systems. The current irradiance conditions are classified in one of eight distinct temporal direct normal irradiance (DNI) variability classes. For each class and lead-time, an upper and lower uncertainty value is derived from historical data, which describes a coverage probability of 68.3%. This database of uncertainty values is based on deviations of the irradiance maps, compared to three reference pyrheliometers in Tabernas, Andalucia over two years (2016 and 2017). Increased uncertainties due to transient effects are considered by detecting transient zones close to cloud shadow edges within the DNI map. The width of the transient zones is estimated by the current average cloud height, cloud speed, lead-time, and Sun position. The final spatially resolved uncertainties are validated with three reference pyrheliometers, using a data set consisting of the entire year 2018. Furthermore, we developed a procedure based on the DNI temporal variability classes to estimate the expected average uncertainties of the nowcasting system at any geographical location. The novel method can also be applied for global tilted or horizontal irradiance and is assumed to improve the applicability of the ASI nowcasts.
A Theoretical Analysis for Improving Aerosol-Induced CO2 Retrieval Uncertainties Over Land Based on TanSat Nadir Observations Under Clear Sky Conditions
Authors: Chen Xi , Liu Yi , Yang Dongxu , Cai Zhaonan , Chen Hongbin , Wang Maohua
Published: May 2019

Aerosols significantly affect carbon dioxide (CO2) retrieval accuracy and precision by modifying the light path. Hyperspectral measurements in the near infrared and shortwave infrared (NIR/SWIR) bands from the generation of new greenhouse gas satellites (e.g., the Chinese Global Carbon Dioxide Monitoring Scientific Experimental Satellite, TanSat) contain aerosol information for correction of scattering effects in the retrieval. Herein, a new approach is proposed for optimizing the aerosol model used in the TanSat CO2 retrieval algorithm to reduce CO2 uncertainties associated with aerosols. The weighting functions of hyperspectral observations with respect to elements in the state vector are simulated by a forward radiative transfer model. Using the optimal estimation method (OEM), the information content and each component of the CO2 column-averaged dry-air mole fraction (XCO2) retrieval errors from the TanSat simulations are calculated for typical aerosols which are described by Aerosol Robotic Network (AERONET) inversion products at selected sites based on the a priori and measurement assumptions. The results indicate that the size distribution parameters (reff, veff), real refractive index coefficient of fine mode (arf) and fine mode fraction (fmf) dominate the interference errors, with each causing 0.2–0.8 ppm of XCO2 errors. Given that only 4–7 degrees of freedom for signal (DFS) of aerosols can be obtained simultaneously and CO2 information decreases as more aerosol parameters are retrieved, four to seven aerosol parameters are suggested as the most appropriate for inclusion in CO2 retrieval. Focusing on only aerosol-induced XCO2 errors, forward model parameter errors, rather than interference errors, are dominant. A comparison of these errors across different aerosol parameter combination groups reveals that fewer aerosol-induced XCO2 errors are found when retrieving seven aerosol parameters. Therefore, the model selected as the optimal aerosol model includes aerosol optical depth (AOD), peak height of aerosol profile (Hp), width of aerosol profile (Hw), effective variance of fine mode aerosol (vefff), effective radius of coarse mode aerosol (reffc), coefficient a of the real part of the refractive index for the fine mode and coarse mode (arf and arc), with the lowest error of less than 1.7 ppm for all aerosol and surface types. For marine aerosols, only five parameters (AOD, Hp, Hw, reffc and arc) are recommended for the low aerosol information. This optimal aerosol model therefore offers a theoretical foundation for improving CO2 retrieval precision from real TanSat observations in the future.
An Agricultural Drought Index for Assessing Droughts Using a Water Balance Method: A Case Study in Jilin Province, Northeast China
Authors: Cao Yijing , Chen Shengbo , Wang Lei , Zhu Bingxue , Lu Tianqi , Yu Yan
Published: May 2019

Drought, which causes the economic, social, and environmental losses, also threatens food security worldwide. In this study, we developed a vegetation-soil water deficit (VSWD) method to better assess agricultural droughts. The VSWD method considers precipitation, potential evapotranspiration (PET) and soil moisture. The soil moisture from different soil layers was compared with the in situ drought indices to select the appropriate depths for calculating soil moisture during growing seasons. The VSWD method and other indices for assessing the agricultural droughts, i.e., Scaled Drought Condition Index (SDCI), Vegetation Health Index (VHI) and Temperature Vegetation Dryness Index (TVDI), were compared with the in situ and multi-scales of Standardized Precipitation Evapotranspiration Index (SPEIs). The results show that the VSWD method has better performance than SDCI, VHI, and TVDI. Based on the drought events collected from field sampling, it is found that the VSWD method can better distinguish the severities of agricultural droughts than other indices mentioned here. Moreover, the performances of VSWD, SPEIs, SDCI and VHI in the major historical drought events recorded in the study area show that VSWD has generated the most sensible results than others. However, the limitation of the VSWD method is also discussed.
Calibration of Wi-Fi-Based Indoor Tracking Systems for Android-Based Smartphones
Authors: Martínez del Horno Miguel , García-Varea Ismael , Orozco Barbosa Luis
Published: May 2019

With the growing development of smartphones equipped with Wi-Fi technology and the need of inexpensive indoor location systems, many researchers are focusing their efforts on the development of Wi-Fi-based indoor localization methods. However, due to the difficulties in characterizing the Wi-Fi radio signal propagation in such environments, the development of universal indoor localization mechanisms is still an open issue. In this paper, we focus on the calibration of Wi-Fi-based indoor tracking systems to be used by smartphones. The primary goal is to build an accurate and robust Wi-Fi signal propagation representation in indoor scenarios.We analyze the suitability of our approach in a smartphone-based indoor tracking system by introducing a novel in-motion calibration methodology using three different signal propagation characterizations supplemented with a particle filter. We compare the results obtained with each one of the three characterization in-motion calibration methodologies and those obtained using a static calibration approach, in a real-world scenario. Based on our experimental results, we show that the use of an in-motion calibration mechanism considerably improves the tracking accuracy.