bluuebunny/crossref_metadata_2025_split huggingface dataset:
[Ni(NHC)2] as a Scaffold for Structurally Characterized trans [H−Ni−PR2] and trans [R2P−Ni−PR2] Complexes
Authors: Sabater Sara , Schmidt David , Schmidt Heidi (née Schneider) , Kuntze‐Fechner Maximilian W. , Zell Thomas , Isaac Connie J. , Rajabi Nasir A. , Grieve Harry , Blackaby William J. M. , Lowe John P. , Macgregor Stuart A. , Mahon Mary F. , Radius Udo , Whittlesey Michael K. 
Published: July 2021

AbstractThe addition of PPh2H, PPhMeH, PPhH2, P(para‐Tol)H2, PMesH2 and PH3 to the two‐coordinate Ni0 N‐heterocyclic carbene species [Ni(NHC)2] (NHC=IiPr2, IMe4, IEt2Me2) affords a series of mononuclear, terminal phosphido nickel complexes. Structural characterisation of nine of these compounds shows that they have unusual trans [H−Ni−PR2] or novel trans [R2P−Ni−PR2] geometries. The bis‐phosphido complexes are more accessible when smaller NHCs (IMe4>IEt2Me2>IiPr2) and phosphines are employed. P−P activation of the diphosphines R2P−PR2 (R2=Ph2, PhMe) provides an alternative route to some of the [Ni(NHC)2(PR2)2] complexes. DFT calculations capture these trends with P−H bond activation proceeding from unconventional phosphine adducts in which the H substituent bridges the Ni−P bond. P−P bond activation from [Ni(NHC)2(Ph2P−PPh2)] adducts proceeds with computed barriers below 10 kcal mol−1. The ability of the [Ni(NHC)2] moiety to afford isolable terminal phosphido products reflects the stability of the Ni−NHC bond that prevents ligand dissociation and onward reaction.
Chemodynamic Therapy Combined with Multifunctional Nanomaterials and Their Applications in Tumor Treatment
Authors: Yu Zhenghao , Hu Yue , Sun Yuan , Sun Tiedong 
Published: July 2021

AbstractDuring the past few decades, radiotherapy and chemotherapy have been the standard approaches for tumor treatments. However, the potential toxic effect and side effects of both radiotherapy and chemotherapy on the human body still cannot be neglected. Given this, the Fenton reaction has become one of the most effective treatment strategies to combat tumor cells. This review aims to summarize the recent advances comprehensively and systematically in chemodynamic therapy (CDT) via the Fenton reaction. In addition, a host of the advanced nano‐multifunctional materials and engineering bacteria used in the Fenton reaction were also summarized. This paper would be helpful to provide guidance and lay firm foundations for future tumor treatment.
Cata‐Annulated Azaacene Bisimides
Authors: Elter Maximilian , Ahrens Lukas , Luo Stella M. , Rominger Frank , Freudenberg Jan , Cao Dennis D. , Bunz Uwe H. F. 
Published: July 2021

AbstractUltra‐electron‐deficient azaacenes were synthesized via Buchwald‐Hartwig coupling of ortho‐diaminoarenes with chlorinated mellophanic diimide followed by oxidation of the intermediate N,N’‐dihydro compounds with MnO2 or PbO2. The resulting cata‐annulated bisimide azaacenes have ultrahigh electron affinities with first reduction potentials as low as −0.35 V recorded for a tetraazapentacene. Attempts to prepare a tetrakis(dicarboximide)tetraazaheptacene resulted in the formation of a symmetric butterfly dimer.
Ionic Liquids [M3+][A−]3 with Three‐Valent Cations and Their Possible Use to Easily Separate Rare Earth Metals
Authors: Rothe Manuel , Tress Martin , Allacher Carina , Nuernberger Patrick , Kunz Werner 
Published: July 2021

AbstractWe introduce a simple way to liquify rare earth metals (REM) by incorporating the corresponding cations, in particular Eu3+, La3+, and Y3+, into polyvalent ionic liquids (ILs). In contrast to conventional methods, this is achieved not by transforming them into anionic complexes, but by keeping them as bare cations and combining them with convenient, cheap and commercially available anions (A) in the form [REM3+][A−]3. To do so, we follow the COncept of Melting Point Lowering due to EThoxylation (COMPLET) with alkyl polyethylene oxide carboxylates as anions. We provide basic properties, such as glass transition temperatures, viscosities, electrical conductivities, as well as water‐octanol partition constants P and show that these ILs have remarkably different properties, despite the similarity of their cations. In addition, we show that the ionic liquids possess interesting luminescent properties as non‐conventional fluorophores.
What Is the Catalytic Mechanism of Enzymatic Histone N‐Methyl Arginine Demethylation and Can It Be Influenced by an External Electric Field?
Authors: Ramanan Rajeev , Waheed Sodiq O. , Schofield Christopher J. , Christov Christo Z. 
Published: July 2021

AbstractInvited for the cover of this issue are Christo Z. Christov and co‐workers at Michigan Technological University and University of Oxford. The image depicts the effects of applying an external electric field on the demethylation of dimethylated arginine substrate by a non‐heme Fe center Histone N‐methyl arginine demethylase. Read the full text of the article at 10.1002/chem.202101174.
Uncommon N‐Methoxyindolediketopiperazines from Acrostalagmus luteoalbus, a Marine Algal Isolate of Endophytic Fungus
Authors: Cao Jin , Li Xiao‐Ming , Li Xin , Li Hong‐Lei , Konuklugil Belma , Wang Bin‐Gui 
Published: July 2021

Main observation and conclusionFour new N‐methoxyindolediketopiperazines (acrozines D—G, 1—4) and six known congeners (5—10) were purified from the organic extract of Acrostalagmus luteoalbus TK‐43, which was a marine algal‐derived fungus obtained from Codium fragile. Their structures were determined by interpretation of NMR and mass spectroscopic data. The structures of compounds 1, 2, and 4 including their absolute configurations were confirmed by single‐crystal X‐ray diffraction, while the absolute configuration of compound 3 was elucidated by comparative analysis of ECD and TDDFT‐ECD calculations. Compounds 1—4, with a unique methoxy substitution at N‐2, were rarely discovered among indolediketopiperazine alkaloids. All these compounds were evaluated for antimicrobial activities against human‐ and aquatic‐pathogenic bacteria and plant‐related pathogenic fungi, with compounds 5 and 7 exhibiting potent activity against Edwardsiella icataluri (MIC = 3 and 5 μmol/L, respectively), while compound 9 displayed a broad spectrum of antibacterial activities. The four new compounds were further tested for anti‐acetylcholinesterase (AChE) properties, and compound 3 exhibited inhibitory activity with IC50 value of 8.4 μmol/L.
Revisiting the fluorescent mosaic technique
Authors: Travis M.F.A. Richard 
Published: July 2021

AbstractA visual art technique first described in an early issue of CR&A is discussed here in the way it has been modified to expand its practicality. As a first‐of‐its‐kind application of additive color mixture in the two‐dimensional visual arts, the fluorescent mosaic technique is considered in terms of its historical context, and its conceptual and technical development are presented as it grew out of an awareness of a theoretical dissonance between the worlds of art and science. Three visual designs created in the additive fluorescent mosaic technique as proof‐of‐concept demonstrations are presented and discussed as they evolved from early methods requiring special lighting, which severely restricted the technique's applicability, to a more broadly functional method requiring only white light that is strong in blue content, such as average daylight. Because digital photography and electronic displays capture the appearance of fluorescent mosaic images quite well, their use as an educational instrument for teaching color mixture theory on a wide‐scale basis is promising. An outline of basic procedures for creating fluorescent mosaic artwork is provided. As a fine art medium, it is an area of visual expression that is virtually unexplored. Lastly, other approaches to creating visual art using luminous mosaic imagery are suggested.
Species–environment relationships of fish and map‐based variables in small boreal streams: Linkages with climate change and bioassessment
Authors: Sutela Tapio , Vehanen Teppo , Jounela Pekka , Aroviita Jukka 
Published: July 2021

AbstractSpecies–environment relationships were studied between the occurrence of 13 fish and lamprey species and 9 mainly map‐based environmental variables of Finnish boreal small streams. A self‐organizing map (SOM) analysis showed strong relationships between the fish species and environmental variables in a single model (explained variance 55.9%). Besides basic environmental variables such as altitude, catchment size, and mean temperature, land cover variables were also explored. A logistic regression analysis indicated that the occurrence probability of brown trout, Salmo trutta L., decreased with an increasing percentage of peatland ditch drainage in the upper catchment. Ninespine stickleback, Pungitius pungitius (L.), and three‐spined stickleback, Gasterosteus aculeatus L., seemed to benefit from urban areas in the upper catchment. Discovered relationships between fish species occurrence and land‐use attributes are encouraging for the development of fish‐based bioassessment for small streams. The presented ordination of the fish species in the mean temperature gradient will help in predicting fish community responses to climate change.
The Role of Grain Boundaries in Charge Carrier Dynamics in Polycrystalline Metal Halide Perovskites
Authors: Gegevičius Rokas , Franckevičius Marius , Gulbinas Vidmantas 
Published: July 2021

AbstractBoundaries of perovskite grains forming polycrystalline films are the most sensitive place for the formation of the defect states and accumulation of impurities. The intra‐bandgap states located at the boundaries forming traps for charge carriers are commonly discussed as causing nonradiative carrier recombination and reducing carrier mobility. Grain boundaries (GB) may also disturb carrier motion by creating scattering centres and barriers, however, their role was less frequently considered. On the other hand, grain boundaries may also facilitate the splitting of exciton states and the generation of free charge carriers. Consequently, the grain boundaries are responsible or affect a wide range of perovskite properties and processes strongly influencing the performance of perovskite‐based optoelectronic devices. Nevertheless, abundant literature data related to the properties of grain boundaries and their influence are highly controversial. In this minireview, we discuss the most importnat literature data related to the structure and properties of grain boundaries and their role in device performance.
Sonogashira Cross‐Coupling Reaction of Bromocyanofluoro Pyridine Compounds: Access to 5‐ and 6‐Alkynylfluoropyridinamidoximes Scaffolds
Authors: Razafindrainibe Franck , Voros Camille , Jagadeesh Yerri , Reddy Nimmakayala Mallikarjuna , Tissier Allan , Mardy Keven , Reihanian‐Hadany Norbert , Brown Richard C. D. , Baati Rachid 
Published: July 2021

AbstractWe disclose a general two‐step procedure to access hitherto unknown and under explored 5‐ and 6‐alkynyl‐3‐fluoro‐2‐pyridinamidoximes from 5‐ and 6‐bromo‐3‐fluoro‐2‐cyanopyridines and a wide range of easily available and bench‐stable terminal alkynes, using Sonogashira cross‐coupling, as the first step. The generation of the polar amidoxime group is realized at a late stage upon treatment of the alkynylfluorocyanopyridine by hydroxylamine. This mild and operationally simple two‐step room temperature process is compatible with enantiopure chiral substrates and various functionality including free alcohols, unprotected and CBz‐protected amines, acetonides, benzyl ethers, amide, imide, di‐substituted alkynes and strained saturated heterocycles.
A highly sensitive magnetic configuration‐based triboelectric nanogenerator for multidirectional vibration energy harvesting and self‐powered environmental monitoring
Authors: Park Minseok , Cho Sumin , Yun Yeongcheol , La Moonwoo , Park Sung Jea , Choi Dongwhi 
Published: July 2021

SummaryVibration energy, which is ubiquitous but usually abandoned energy, has been considered as a promising source of energy to be harvested for future power supply to electronics. In this study, we demonstrate the triboelectric nanogenerator (TENG) with a rationally designed bi‐axial vibration responsive magnetic configuration (BVMC). Oblique placement of two magnets enables the system to be bi‐axially sensitive and the superior response of such BVMC to vibrations is explored for further utilized to harvest multidirectional vibration energy in a single device. Energy harvesting performance of the multidirectional vibration stimuli‐responsive TENG, called MS‐TENG, under various vibration conditions is investigated. In addition, the further development of the MS‐TENG with an additional magnet exhibits the full (three‐dimensional) vibration energy harvesting ability. The MS‐TENG is applied under‐the‐hood of an automobile where typically abandoned vibrations occur frequently. Turning on the engine on the ignition enables the arrayed MS‐TENG to generate a stable output just by engine trembling. Furthermore, the normal human motion‐driven vibration is used to charge the commercial capacitor to wirelessly transmit the signal including information of ambient temperature and humidity from the Bluetooth thermo‐hygrometer sensor. Consequently, the present TENG with simple but bi‐axially sensitive magnetic configuration has a great potential to effectively harvest the multidirectional and low‐frequency vibrations around us for future feasible applications.
Larger cells have relatively smaller nuclei across the Tree of Life
Authors: Malerba Martino E. , Marshall Dustin J. 
Published: July 2021

AbstractLarger cells have larger nuclei, but the precise relationship between cell size and nucleus size remains unclear, and the evolutionary forces that shape this relationship are debated. We compiled data for almost 900 species – from yeast to mammals – at three scales of biological organisation: among-species, within-species, and among-lineages of a species that was artificially selected for cell size. At all scales, we showed that the ratio of nucleus size to cell size (the ‘N: C’ ratio) decreased systematically in larger cells. Size evolution appears more constrained in nuclei than cells: cell size spans across six orders of magnitude, whereas nucleus size varies by only three. The next important challenge is to determine the drivers of this apparently ubiquitous relationship in N:C ratios across such a diverse array of organisms.
Metapopulation structure modulates sexual antagonism
Authors: Rodriguez-Exposito E. , Garcia-Gonzalez F. 
Published: July 2021

AbstractDespite the far-reaching evolutionary implications of sexual conflict, the effects of metapopulation structure, when populations are subdivided into several demes connected to some degree by migration, on sexual conflict dynamics are unknown. Here, we used experimental evolution in an insect model system, the seed beetle Callosobruchus maculatus, to assess the independent and interacting effects of selection histories associated with mating system (monogamy vs. polygamy) and population subdivision on sexual conflict evolution. We confirm traditional predictions from sexual conflict theory by revealing increased resistance to male harm in females from populations with a history of intense sexual selection (polygamous populations) compared to females from populations with a history of relaxed sexual selection (monogamous populations). However, selection arising from metapopulation structure reversed the classic pattern of sexually antagonistic coevolution and led to reduced resistance in females from polygamous populations. These results underscore that population spatial structure moderates sexual selection and sexual conflict, and more broadly, that the evolution of sexual conflict is contingent on ecological context. The findings also have implications for population dynamics, conservation biology, and biological control.
Structural modification and biological activities of carboxymethyl Pachymaran
Authors: Yan You‐Yu , Yuan Shuai , Ma Hao‐Hai , Zhang Xi‐Feng 
Published: July 2021

AbstractPolysaccharides are good chelating agents for metal ions, which are often used to synthesize polysaccharide metal ion complexes. With carboxymethyl pachymaran (CMP) as the substrate, carboxymethyl pachymaran iron (CMPF), carboxymethyl pachymaran selenium (CMPS), and carboxymethyl pachymaran zinc (CMPZ) were synthesized by response surface methodology, and their biological characteristics were studied. The results showed that the CMP was a β‐polysaccharide, and the degree of carboxymethylation was 0.6352. The polysaccharide metal ion complexes were characterized by physicochemical methods, scanning electron microscopy, Fourier transform infrared spectroscopy, circular dichroism spectroscopy, and nuclear magnetic resonance spectroscopy. All the polysaccharides and complexes possessed antioxidant activity in vitro with scavenging activities to ABTS, superoxide anions, and ferrous ions. CMPF, CMPS, and CMPZ caused significant inhibition of A2780 cell proliferation, promoted the production of reactive oxygen species, and induced apoptosis in a human ovarian cancer cell line (A2780 cells). These results suggest that the CMP complex may be an effective candidate drug for cancer treatment in the field of functional food and pharmacology.
Stock market tail risk, tail risk premia, and return predictability
Authors: Suh Sangwon , Yoo Eungyu , Yoon Sun‐Joong 
Published: July 2021

AbstractIn this study, we use the S&P 500 options prices to derive various tail risk indexes. We then decompose the option‐implied tail risk indexes into the conditional tail risk of stock returns and equity tail risk premia. We examine the predictive power of the conditional tail risks and equity tail risk premia for various stock portfolio returns. The results demonstrate that the tail risk indicators possess additional predictive power for stock returns in the presence of extant risk indicators and other return predictor variables.
High Prevalence of Transjugular Intrahepatic Portosystemic Shunt Creation Without Prior Endoscopy During Acute Variceal Bleeding Hospitalization in the United States
Authors: Trivedi Premal S. , Jensen Alexandria M. , Brown Matthew A. , Morgan Rustain L. , Lindrooth Richard C. , Ryu Robert K. , Ho P. Michael , Kriss Michael S. 
Published: July 2021

Current clinical guidelines by both American Association for the Study of Liver Disease and European Association for the Study of the Liver recommend endoscopy in all patients admitted with acute variceal bleeding within 12 hours of admission. Transjugular intrahepatic portosystemic shunt (TIPS) creation may be considered in patients at high risk if hemorrhage cannot be controlled endoscopically. We conducted a cross‐sectional observational study to assess how frequently TIPS is created for acute variceal bleeding in the United States without preceding endoscopy. Adult patients undergoing TIPS creation for acute variceal bleeding in the United States (n = 6,297) were identified in the last 10 available years (2007‐2016) of the National Inpatient Sample. Hierarchical logistic regression was used to examine the relationship between endoscopy nonutilization and hospital characteristics, controlling for patient demographics, income level, insurance type, and disease severity. Of 6,297 discharges following TIPS creation for acute variceal bleeding in the United States, 31% (n = 1,924) did not receive first‐line endoscopy during the same encounter. Rates of “no endoscopy” decreased with increasing population density of the hospital county (nonmicropolitan counties 43%, n = 114; mid‐size metropolitan county 35%, n = 513; and central county with >1 million population 23%, n = 527) but not by hospital teaching status (n = 1,465, 32% teaching vs. n = 430, 26% nonteaching; P = 0.10). Higher disease mortality risk (odds ratio, 0.42; 95% confidence interval, 0.22‐0.80; P = 0.02) was associated with lower odds of noncompliance. Conclusion: One third of all patients undergoing TIPS creation for acute variceal bleeding in the United States do not receive first‐line endoscopy during the same encounter. Patients admitted to urban hospitals are more likely to receive guideline‐concordant care.
Organisation of the State, model of health system and COVID‐19 health outcomes in six European countries, during the first months of the COVID‐19 epidemic in 2020
Authors: Simões Jorge , Magalhães João Paulo Moreira , Biscaia André , da Luz Pereira António , Augusto Gonçalo Figueiredo , Fronteira Inês 
Published: July 2021

AbstractThe time and type of the States' responses to the COVID‐19 pandemic varied with the severity of the epidemiological situation, the perceived risk, the political organisation and the model of health system of the country. We discuss the response of Germany, Spain, France, Italy, Portugal and the United Kingdom during the first months of the COVID‐19 epidemic in 2020, considering the political organisation of the country and its health system model. We analyse public health measures implemented to contain or mitigate the pandemic, as well as those related to governance, resources and reorganisation of services, financing mechanisms, response of the health system itself and health outcomes. To measure the burden of COVID‐19, we use several indicators. The adoption of measures, to contain and mitigate epidemic varied in degree and time of adoption. All countries reorganised their governance structure and the provision of care, despite the differences in political models and health systems (ranging from a more unitary and centralised political organisational model—France and Portugal; to a decentralised matrix—Germany, Spain, Italy and the United Kingdom). Rather than the differences in political models and health systems, the explanation for the success in tackling the epidemic seems to lay in other social determinants of health.
Heat and mass transport impact on MHD second‐grade fluid: A comparative analysis of fractional operators
Authors: Rehman Aziz Ur , Riaz Muhammad Bilal , Akgül Ali , Saeed Syed Tauseef , Baleanu Dumitru 
Published: July 2021

AbstractThe effect of the magnetic flux plays a major role in convective flow. The process of heat transfer is accompanied by a mass transfer process; for instance, condensation, evaporation, and chemical process. Due to the applications of the heat and mass transfer combined effects in different fields, the main aim of this paper is to do a comprehensive analysis of heat and mass transfer of magnetohydrodynamic (MHD) unsteady second‐grade fluid in the presence of ramped conditions. The new governing equations of MHD second‐grade fluid have been fractionalized by means of singular and nonsingular differentiable operators. To have an accurate physical significance of imposed conditions on the geometry of second‐grade fluid, the constant concentration with ramped temperature and ramped velocity is considered. The fractional solutions of temperature, concentration, and velocity have been investigated by means of integral transform and inversion algorithm. The influence of physical parameters and flow is analyzed graphically via computational software (MATHCAD‐15). The velocity profile decreases by increasing the Prandtl number. The existence of a Prandtl number may reflect the control of the thickness and enlargement of the thermal effect.