bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diuranium(IV) Carbide Cluster U2C2 Stabilized inside Fullerene Cages
Authors: Abella Guzman Laura 
Published: December 2020

Novel actinide cluster fullerenes, U2C2@I
h(7)-C80 and U2C2@D
3h(5)-C78, were synthesized and fully characterized by mass spectrometry, single crystal X-ray crystallography, UV-vis-NIR , Raman spectroscopy, IR spectroscopy, as well as density functional and multireference wavefunction calculations. The encapsulated U2C2 is the first example of a uranium carbide cluster featuring two U centers bridged by a C≡C unit. The U-C bond distances in these U2C2 clusters are in the range between 2.130-2.421 Å. While the U2C2cluster in U2C2@C80 adopts a butterfly-shaped geometry with a U-C2-U dihedral angle of 112.716 °and a U-U distance of 3.855 Å, the U-U distance in U2C2@C78 is 4.164 Å and the resulting U-C2-U dihedral angle is increased to 149.084 °. The combined experimental and quantum-chemical results suggest that the formal U oxidation state is +IV in the U2C2 cluster, and each U center transfers three electrons to the C2n cage and one electron to C2. Different from the strong U=C covalent bonding reported for U2C@C80, the U-C bonds in U2C2 are less covalent and predominantly ionic. The C-C triple bond is somewhat weaker than in HCCH and the C-C -bonds undergo donation bonding with the U centers. This study demonstrates that the combination of the unique encapsulation effect of fullerene cages and the variable oxidation states of actinide elements can lead to the stabilization of novel actinide clusters which are not accessible by conventional synthetic methods.

Figure 1
Durability of Graphene-Supported Iron Phthalocyanine in Acidic and Basic Media: A Theoretical Study
Authors: Orellana Walter , Tasca Federico 
Published: December 2020

The oxygen reduction reaction (ORR) is a crucial chemical process, which contributes significantly to the energy efficiency of fuel cells and metal-air batteries. Although Pt and its alloys are known as the most efficient catalysts for ORR, its high costs and scarcity limits their applications. Alternatively, Fe–N–C catalysts have attracted the most interest owing to their low-cost and facile preparation methods. Metal macrocycles, such as iron phthalocyanines (FePc), are the precursors most widely used to prepare the ORR catalysts in fuel cells and metal-air batteries. However, limited progress has been made in improving their electrocatalytic activity and durability. In particular, FePc has demonstrated to suffer from severe degradation in the acidic fuel cell environments, commonly attributed to demetalation and/or degradation by ORR intermediates. The typical life cycle for FePc catalysts is less than 100 cycles in either acidic or basic media.
In this work we use ab initio molecular dynamic (MD) simulations to investigate the degradation of graphene-supported FePc in acidic and basic media at operational conditions. The acidic media includes hydrochloric, acetic, sulfuric and phosphoric acids, whereas the basic media includes sodium hydroxide. The solution concentration in all cases is 1M. The MD simulations were performed by dispersion-corrected DFT calculations, using periodic boundary conditions, at 80°C through a simulation time of 2 ps. Our results show that demetalation is not the cause of the FePc degradation, instead we find that for acetic and hydrochloric acids, the acid anion binds to the Fe center, with binding energies of -1.1 and -6.5 eV, respectively. The formation of this ligand would hinder the O2 adsorption on the metal center, limiting the FePc catalytic activity. On the contrary, for phosphoric and sulfuric acids, as well as for basic media, the ion-Fe binding is energetically unlikely, enabling the O2-metal interaction. Therefore, our results suggest that the catalytic activity and degradation of FePc are connected to the acidic media involved.
This work was supported by ANID/FONDECYT under Grant No. 1170480
Synthesis and Characterization of Nanocrystalline Boron-Doped Diamond Electrodes: Towards Electrochemical Reduction of CO2
Authors: Ashcheulov Petr , Hak Ondrej , Taylor Andrew , Davydova Marina , More-Chevalier Joris , Mortet Vincent 
Published: December 2020

The continuous increase of atmospheric carbon dioxide (CO2) concentration along with pollution of waters by organic wastes have led the scientific community to investigate novel strategies to address these worldwide environmental problem. Electrochemical methods are a promising approach to convert CO2 into a variety of useful chemicals and to remove contaminants from wastewater [1,2]. Nevertheless, it is necessary to develop inexpensive and chemically robust electrodes with long life-time in harsh electrochemical conditions for these processes to be efficient and economically viable.
Boron-doped diamond (BDD) has been recently shown to be a promising material for electrochemical reduction of CO2 into formic acid and formaldehyde [3]. In contrast to thick microcrystalline BDD films, thin nanocrystalline BDD layers (thickness of 100 - 500 nm) provide a higher degree of flexibility in material properties, e.g. due to a variable diamond/non-diamond content, and allows efficient bottom-up nanostructuring, e.g. BDD growth on porous templates [4].
In this work, we investigate nanocrystalline boron-doped diamond and composite BDD/SiC electrodes synthesized via microwave plasma enhanced chemical vapor deposition (MW PE CVD) method at different deposition temperatures (250 - 750°C) towards electrochemical reduction of CO2 in water-based electrolytes [5]. Fabricated electrodes were characterized by a variety of techniques, including Raman spectroscopy, scanning electron microscopy imaging and electrical conductivity measurements. Electrochemical properties of nanocrystalline BDD electrodes of various thickness, boron content and electrical conductivity were studied.
This work has been supported by the Grant Agency of the Czech Republic (GACR) contract 19-09784Y.
[1] I. Sirés et al., Environ Sci Pollut Res (2014) 21: 8336.
[2] A. Goeppert et al., Chem. Soc. Rev. (2014), 43, 7995-8048.
[3] K. Nakata et al., Angew. Chem. Int. Ed. (2014), 53, 871 –874.
[4] V Petrák et al., Carbon (2017), 114, 457.
[5] A. Taylor et al., J. Alloys. Compd., (2019) 800, 327-333
Cost-Effective and Eco-Friendly Carbon-Based Nanomaterials in Wearable Energy Storage Devices
Authors: Das Himadri Tanaya 
Published: December 2020

The growing concerns of pollution and subsequent climate change have garnered researchers and enthusiasts all over the world to strive forward towards a sustainable and renewable energy economy. Nevertheless the energy production is not sufficient enough until, it is stored and utilised adequately. Henceforth, the electrochemical energy storage devices such batteries and supercapacitors have find a prominent place in the list. Quite recently, wearable energy storage devices can be a game changing for the energy storage industries. Thus, the search of competent electrodes for potential device is incalculable. The nanomaterials based electrodes are attracting the interest of scientist because of their efficient capacity in energy storage.
In the nanomaterials, the physical and chemical properties can be extensively tuned by parameters such as morphology, distributions, composites etc. Besides that the electrolyte in an energy storage device also plays a vital role for the operating potential and cycle life of the device. The conductive electrolyte provides pathway for easy ion movements during charge and discharge of device. The carbon-based nanomaterials such as graphene, carbon quantum dots, activated carbon etc., can be used as negative electrode. These can be also used as positive electrodes when composite with some metal oxides, hydroxides or sulphides. These electrode materials can be synthesised by chemical methods or by carbonising the natural products such as dry leaves, fruits, peals, milk etc. Most interesting process to extract carbon is recycling the wastes viz., tyres, shoot, dry cells etc. to have an eco-friendly environment. Thus realize highly stable device, the development of carbon-based electrode materials is imperative. In this work, generation of efficient carbon-based electrodes by recycling of waste for energy storage devices will be presented in details.
The wearable energy storage devices are emerging area for future electronics technology. Wearables are not just a smartwatch, but a whole range of wearable devices, including biosensors, biomedical equipment, renewable charged devices etc. These devices have tremendous potential to improve quality of life and safety. Researchers and industries are involved in developing carbon-based electrodes for wearable sensors and self-powered devices to create a new generation of wearables with high outcomes to meet the consumer demand. Henceforth, the generated carbon-based materials can be potential electrodes in wearable energy storage devices.
Key words: Nanomaterials, Recycling, Carbon, Energy, Wearable Electronics, Capacity
Understanding the Structure and Speciation of Molten LiCl-KCl Using Raman and Ultraviolet-Visible-Near IR Spectroscopic Techniques
Authors: Moon Jeremy , Phillips William C. , Gakhar Ruchi , Chidambaram Dev 
Published: December 2020

Pyrochemical reprocessing (pyroprocessing) of used nuclear fuel (UNF) is a promising pathway towards closing the nuclear fuel cycle by recycling actinides into new fuel and providing the means to generate durable wasteforms for portions of the UNF that are not able to be recycled. One of the most significant challenges in the advancement of this technology is developing a more complete understanding of the chemistry of the electrolyte molten salts used in the electrorefining process, where fission products, transuranic elements and fuel elements are anodically dissolved into a LiCl-KCl electrolyte, forming a chemically complex mixture. To enhance our understanding of the chemistry of the mixture of molten salt electrolyte and UNF we are studying the structure and speciation of lanthanide and actinide elements dissolved in LiCl-KCl using Raman and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. These techniques are starting to provide information on the coordination, symmetry, and electronic structure of the dissolved species, which will result in a more complete understanding of the chemistry of these solutions. Results of a Raman spectroscopy study of mixtures of NdCl3, SmCl3, CeCl3, and EuCl3 with LiCl-KCl and LiCl-KCl-UCl3 and the development of a system to conduct Raman and UV-Vis-NIR spectroscopy and spectroelectrochemistry will be presented.
Acknowledgements: This work was performed under the auspices of the Department of Energy (DOE) under contracts DE-NE0008889, and the US Nuclear Regulatory Commission (NRC) under contracts NRC-HQ-13-G-38-0027 and 31310018M0032. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively. For support of furnace design and fabrication work at INL, RG and WCP acknowledge the Laboratory Directed Research & Development (LDRD) Program under DOE Idaho Operations Office Contract DE-AC07-05ID14517 and a subcontract under LDRD (INL) to University of Nevada, Reno via award number 204471 (UNR award AWD-01-00001719); this design served as starting iteration for this work. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1447692. One of the authors, JM, acknowledges the Graduate Research Fellowship from the US National Science Foundation.
Studying Proton Conducting Ceramic Electrolyte Stability with in Situ Raman Spectroscopy
Authors: Welander Märtha , Goettlich Daniel M. , Henning Tanner J. , Walker Robert A. 
Published: December 2020

Ceramic-based proton conducting fuel cells (PCFCs) are attractive devices for directly converting chemical energy to electrical energy. Like conventional solid oxide fuel cells (SOFCs), PCFCs are fuel flexible and efficient. Because PCFC electrolytes conduct protons rather than oxides, these devices can function between 400˚C and 600˚C, temperatures that are much lower than the ≥700˚C required for SOFC operation. PCFC technology remains relatively new, however, meaning that fundamental questions about electrochemical redox mechanisms, material compatibility and device resilience must be answered before PCFCs become a viable technology for commercial development.
In this work, we use in situ vibrational Raman spectroscopy and ex situ XPS to examine the chemical stability of yttria-stabilized barium zirconate (BZY) and ceria doped BZY (BZCY) – both common PCFC electrolytes – as a function of temperature and chemical stress. In particular, in situ Raman data show that electrolyte surface and near surface composition is sensitive to steam in reducing environments with new features appearing in vibrational spectra. (The reducing environment consisted of 25% H2 in Ar; all humidified conditions included 3% H2O from running the incident gas(es) through a room temperature bubbler.) Spectral changes indicate that that the electrolyte structure and/or composition is changing on the electrolyte surface and in the near surface region (as defined by the penetration depth of the incident Raman excitation light). These changes are reversible and vibrational spectra return to their original appearance when steam is removed from the reducing atmosphere. Two important points to note are 1) new spectral features only appear within a limited temperature window between 300˚C and 450˚C and 2) new spectral features do not appear when the ambient atmosphere is inert (Ar), inert with steam (Ar with 3% H2O), or simply a reducing atmosphere (H2 in Ar). While spectral changes are reversible, the steam-altered electrolytes can be isolated by quickly cooling materials showing extraneous vibrational features back to room temperature under a humidified environment. This ability allows for additional ex situ analysis using conventional surface science methods. XPS data suggest that humidified H2 leads to enhanced Ba content on the electrolyte surface raising interesting questions about the role(s) played by surface segregation and secondary phase formation on the catalytic activity and charge transport properties of PCFC electrolytes.
High Temperature Corrosion Resistance in Molten Salts in Solar Power Concentration Plants: High Temperature Corrosión Monitoring in Dynamic and Static Conditions
Authors: Lasanta Maria Isabel , De Miguel Maria teresa , Garcia Martin Gustavo , Illana Andrea , Perez Trujillo Francisco Javier 
Published: December 2020

The actual technology for solar power plants-CSP have termal storage system composed by molten salts. Molten salts technology means electrochemical electrolytes in contact with materials, and in this case high temperature molten salts. which are an ionic electrolyte. In order to follow up the evolution of the sal chemistry, i.e. concentrating the impurities such as chlorides and sulphates, and to monitor the corrosión rate and corrosión mechanism of structural materials, electrochemical sensors have been developed and patented. On the other hand, in order to check the reliabilify and performance of the sensors, static and dynamic test have been performed in a pilot plant.
Moreover, his study assessed the behaviour of a constructive material in CSP plants, namely ferritic-martensitic steel, with molten NaNO3/KNO3 (60/40 wt%), also known as Solar Salt. To this end, EIS is presented as a suitable technique to evaluate and monitor the resistance of this material to Solar Salt at 580 °C. Tests were performed up to 1000 h and results were also supported by gravimetric and microstructural characterisation of the samples and chemical analysis of the salt. According to the EIS results, a diffusion-controlled reaction occurred during contact, which indicates that the corrosion process follows a porous layer mechanism. The results also indicated variations in corrosion layer thickness and instability of the salt during the whole test. The EIS results were also used for determining the corrosion rate, this being estimated at ~300 µm year−1. Results obtained by EIS were in line with the behaviour of P91 steel as measured by gravimetric, morphological and chemical analysis. Thus, the results confirm the suitability of EIS for monitoring corrosion processes in real-time of constructive materials in CSP plants.
Plasma Sulfur Amino Acids and Risk of Cerebrovascular Diseases
Authors: Vinknes Kathrine J. , Refsum Helga , Turner Cheryl , Khaw Kay-Tee , Wareham Nicholas J. , Forouhi Nita G. , Imamura Fumiaki 
Published: December 2020

Background and Purpose:
B-vitamin supplements lower circulating concentrations of homocysteine and may reduce stroke incidence. Homocysteine concentrations are associated with the incidence of stroke but other sulfur-containing compounds in the related metabolic pathway have not yet been investigated for an association with incident cerebrovascular diseases.

Methods:
Nested within the EPIC (European Prospective Investigation Into Cancer and Nutrition)-Norfolk cohort, we established a case-control study with 480 incident cases of cerebrovascular diseases and 480 controls matched by age, sex, and year of baseline examination (1993–1997). Using baseline plasma samples, we assayed sulfur-containing compounds including methionine, homocysteine, cystathionine, cysteine, glutathione, and taurine with liquid chromatography–tandem mass spectrometry. We examined the association of concentrations of each of the compounds and the ratio of methionine to homocysteine (representing activity of one-carbon metabolism) with risk of incident cerebrovascular diseases, adjusted for potential confounders.

Results:
Plasma methionine and the methionine/homocysteine ratio were inversely associated with risk of cerebrovascular diseases, with odds ratios per 1 SD of 0.83 (95% CI, 0.72–0.96) and 0.82 (95% CI, 0.71–0.95), respectively. The association of methionine remained significant after adjustment for homocysteine. None of the other examined compounds was significantly associated with incident cerebrovascular diseases.

Conclusions:
These findings suggest that greater availability of methionine, an essential amino acid, may play a role in the prevention of cerebrovascular diseases and explain the previously recognized link between elevated homocysteine and stroke. Further research is needed to determine causation and the potential of circulating methionine as a target in cerebrovascular disease prevention.
Qualitative and Quantitative Wall Enhancement on Magnetic Resonance Imaging Is Associated With Symptoms of Unruptured Intracranial Aneurysms
Authors: Fu Qichang , Wang Yuting , Zhang Yi , Zhang Yong , Guo Xinbin , Xu Haowen , Yao Zhiqiang , Wang Meng , Levitt Michael R. , Mossa-Basha Mahmud , Zhu Jinxia , Cheng Jingliang , Guan Sheng , Zhu Chengcheng 
Published: December 2020

Background and Purpose:
Aneurysmal wall enhancement (AWE) on vessel wall magnetic resonance imaging (VW-MRI) has been described as a new imaging biomarker of unstable unruptured intracranial aneurysms (UIAs). Previous studies of symptomatic UIAs are limited due to small sample sizes and lack of AWE quantification. Our study aims to investigate whether qualitative and quantitative assessment of AWE can differentiate symptomatic and asymptomatic UIAs.

Methods:
Consecutive patients with UIAs were prospectively recruited for vessel wall magnetic resonance imaging at 3T from October 2014 to October 2019. UIAs were categorized as symptomatic if presenting with sentinel headache or oculomotor nerve palsy directly related to the aneurysm. Evaluation of wall enhancement included enhancement pattern (0=none, 1=focal, and 2=circumferential) and quantitative wall enhancement index (WEI). Univariate and multivariate analyses were used to identify the parameters associated with symptoms.

Results:

Two hundred sixty-seven patients with 341 UIAs (93 symptomatic and 248 asymptomatic) were included in this study. Symptomatic UIAs more frequently showed circumferential AWE than asymptomatic UIAs (66.7% versus 17.3%,
P
<0.001), as well as higher WEI (median [interquartile range], 1.3 [1.0–1.9] versus 0.3 [0.1–0.9],
P
<0.001). In multivariate analysis, both AWE pattern and WEI were independent factors associated with symptoms (odds ratio=2.03 across AWE patterns [95% CI, 1.21–3.39],
P
=0.01; odds ratio=3.32 for WEI [95% CI, 1.51–7.26],
P
=0.003). The combination of AWE pattern and WEI had an area under the curve of 0.91 to identify symptomatic UIAs, with a sensitivity of 95.7% and a specificity of 73.4%.

Conclusions:
In a large cohort of UIAs with vessel wall magnetic resonance imaging, both AWE pattern and WEI were independently associated with aneurysm-related symptoms. The qualitative and quantitative features of AWE can potentially be used to identify unstable intracranial aneurysms.
Grenzland als Synergie- und Dysergiezone
Authors: Donec Pavel N. 
Published: December 2020

Abstract
The author discusses reasons for the scientific interest on the definition of “border / borderland / boundary” in many research-fields, various types of which are described in the article. It is suggested that at least two of them – “threshold” and “mixed zone” – are significantly marked by processes of syn-/ and dysergy. For this reason, the category of “border / borderland / boundary” should be included into the terminological instrumentarium of synergetics and systems theory.
Konzepte CONTACT ZONE und BORDER AREA in der Archäologie
Authors: Petlyuchenko Nataliya 
Published: December 2020

Abstract
The article provides results of a cognitive analysis into the conceptual opposition of CONTACT ZONE vs. BORDER AREA in English and German languages highlighting problems related to their definition in history, linguistics, communication studies, education, etc. The author discusses a series of issues concerning the typology of contact zones in sciences and humanities, offers definitions of the concepts of CONTACT ZONE and BORDER AREA, identifies their constitutive characteristics: motivation (origin) of the concept and types of sub-concepts, type/number of contact cultures and the nature of their relationship, inner structure of a zone and its size, stability/transitivity of a zone, interculturalism/hybridity, etc. The proposed linguistic interpretation of the concept of CONTACT ZONE in archeological discourse contributes to the refinement of the terminological apparatus used by archaeologists specializing in contact zone studies and complex systems of boundaries allowing a more sophisticated way for analyzing ethno-archaeological contact zones as a hypernym-hyponym relationship with several border areas within one contact zone, and provides an ideal-type model of CONTACT ZONE for further interdisciplinary research.
Deprivation or Circumvention of the UN’s Immunity
Authors: Okada Yohei 
Published: December 2020

Abstract
The immune system is supposed to protect one’s body from harmful germs, but sometimes it may attack a healthy part of the body itself—this is called an ‘autoimmune disease’. Although the founders of the United Nations (UN) equipped it with such immunities as are necessary for the fulfilment of its purposes, it seems that its jurisdictional immunity is sometimes more detrimental to its proper functioning than protective of it, especially in the context of peacekeeping. The present study aims to discover a cure for this autoimmune disease. Immunities are, in general, under attack because they serve as insurmountable hurdles to holding those who exercise public authority accountable before domestic courts. Peacekeepers may harm the local population, but the UN’s immunity leads to the denial of justice in cases of third-party claims, which put pressure on the UN. However, neither deprivation nor circumvention of the UN’s jurisdictional immunity is a safe and holistic cure for this autoimmune disease. What we need to ensure is that the immune system functions as designed.