bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spin‐State Variations of Iron(III) Complexes with Tetracarbene Macrocycles
Authors: Schremmer Claudia , Cordes (née Kupper) Claudia , Klawitter Iris , Bergner Marie , Schiewer Christine E. , Dechert Sebastian , Demeshko Serhiy , John Michael , Meyer Franc 
Published: January 2019

AbstractStarting from their six‐coordinate iron(II) precursor complexes [L8RFe(MeCN)]2+, a series of iron(III) complexes of the known macrocyclic tetracarbene ligand L8H and its new octamethylated derivative L8Me, both providing four imidazol‐2‐yliden donors, were synthesized. Several five‐ and six‐coordinate iron(III) complexes with different axial ligands (Cl−, OTf−, MeCN) were structurally characterized by X‐ray diffraction and analyzed in detail with respect to their spin state variations, using a bouquet of spectroscopic methods (NMR, UV/Vis, EPR, and 57Fe Mößbauer). Depending on the axial ligands, either low‐spin (S=1/2) or intermediate‐spin (S=3/2) states were observed, whereas high‐spin (S=5/2) states were inaccessible because of the extremely strong in‐plane σ‐donor character of the macrocyclic tetracarbene ligands. These findings are reminiscent of the spin state patterns of topologically related ferric porphyrin complexes. The ring conformations and dynamics of the macrocyclic tetracarbene ligands in their iron(II), iron(III) and μ‐oxo diiron(III) complexes were also studied.
Copper‐Photocatalyzed Borylation of Organic Halides under Batch and Continuous‐Flow Conditions
Authors: Nitelet Antoine , Thevenet Damien , Schiavi Bruno , Hardouin Christophe , Fournier Jean , Tamion Rodolphe , Pannecoucke Xavier , Jubault Philippe , Poisson Thomas 
Published: January 2019

AbstractThe copper‐photocatalyzed borylation of aryl, heteroaryl, vinyl and alkyl halides (I and Br) was reported. The reaction proceeded using a new heteroleptic Cu complex under irradiation with blue LEDs, giving the corresponding boronic‐acid esters in good to excellent yields. The reaction was extended to continuous‐flow conditions to allow an easy scale‐up. The mechanism of the reaction was studied and a mechanism based on a reductive quenching (CuI/CuI*/Cu0) was suggested.
Transition‐Metal‐Induced Rearrangement of [(PhSn)4S6] Towards Ternary CuI/Sn/S or CuII/Sn/S Clusters
Authors: Dornsiepen Eike , Weigend Florian , Dehnen Stefanie 
Published: January 2019

AbstractDirect access of ternary copper‐tin sulfide clusters by reactions of a binary organotin sulfide cluster, [(PhSn)4S6] (A), with transition metal complexes was achieved for the first time without extra addition of further chalcogenide sources. This indicates that an in situ rearrangement of the inorganic core takes place even without initial formation of anionic fragments. The use of [Cu(PPh3)3Cl] or [Cu(PPh3)2Cl2] as reactants yielded the ternary clusters [(CuPPh3)4(PhSn)18Cu6S31Cl2] (1) and [{Cu(PPh3)2}2(PhSn)3(SnCl)S8] (2), respectively. Whereas 1 represents the largest neutral Cu/Sn/S cluster known to date, compound 2, which is the first example of a ternary Cu/Sn/E (E=S, Se) cluster containing copper in the +II oxidation state, may be viewed as a very early stage of cluster formation. Apparently, the presence of CuII inhibits effective cluster growth, which rationalizes the lack of such species so far. The two ternary clusters exhibit very similar optical absorption energies despite their markedly different cluster sizes. According to time‐dependent DFT calculations, this is due to different characters of the electronic excitation in the triplet compound 2, as compared to the excitation of the closed shell cluster 1, which serve to compensate for the different extensions of the clusters.
Synthesis of Long‐Chain β‐Lactones and Their Antibacterial Activities against Pathogenic Mycobacteria
Authors: Santucci Pierre , Dedaki Christina , Athanasoulis Alexandros , Gallorini Laura , Munoz Anaïs , Canaan Stéphane , Cavalier Jean‐François , Magrioti Victoria 
Published: January 2019

AbstractIn the quest for new antibacterial agents, a series of novel long‐ and medium‐chain mono‐ and disubstituted β‐lactones was developed. Their activity against three pathogenic mycobacteria—M. abscessus,M. marinum, andM. tuberculosis—was assessed by the resazurin microtiter assay (REMA). Among the 16 β‐lactones synthesized, only 3‐hexadecyloxetan‐2‐one (VM005) exhibited promising activity againstM. abscessus, whereas most of the β‐lactones showed interesting activities againstM. marinum, similar to that of the classical antibiotic, isoniazid. RegardingM. tuberculosis, six compounds were found to be active against this mycobacterium, with β‐lactone VM008 [trans‐(Z)‐3‐(hexadec‐7‐en‐1‐yl)‐4‐propyloxetan‐2‐one] being the best growth inhibitor. The promising antibacterial activities of the best compounds in this series suggest that these molecules may serve as leads for the development of much more efficient antimycobacterial agents.
Coupled actuators with a mechanically synchronized phase during MR elastography: A phantom feasibility study
Authors: Neumann Wiebke , Lehnart Vanessa R. , Vetter Yannik , Bichert Andreas , Schad Lothar R. , Zöllner Frank G. 
Published: January 2019

AbstractIntroductionMagnetic resonance elastography (MRE) is an MR imaging method for the quantification of spatial stiffness of soft tissues using mechanically induced dynamic shear waves. In some applications, the penetration of shear waves can be limited through attenuation and shadowing of the waves. In order to increase the actuator performance, we present a dual driver approach to compensate for shear wave attenuation and to achieve better coverage over the entire region of interest.Materials and Methods(a) We designed pneumatic turbines that created a sinusoidal centrifugal force due to an eccentric weight. Two turbines were connected in‐phase with each eccentric weight having the same angular position relative to its pivot point. (b) We developed a tissue elasticity mimicking abdominal phantom. (c) The phantom served as a test object to investigate the feasibility to generate shear waves at two surface origins with the dual actuator system and to compare it against a single actuation setup.Results and DiscussionA stable phase relationship of the shear waves generated by the turbines was achieved as the positions of the eccentric weights were mechanically fixed. The abdominal phantom yielded sufficient MR signal. Liver and rib cage were clearly visible in MR imaging. The shear waves generated by the dual turbine propagated through the region of interest. Our turbine design is reproducible through 3D printing and can be integrated into existing clinical equipment for 1.5 T and 3 T scanners.
Are we meeting the informational needs of cancer patients and families? Perception of physician communication in pediatric oncology
Authors: Levine Deena R. , Liederbach Erik , Johnson Liza‐Marie , Kaye Erica C. , Spraker‐Perlman Holly , Mandrell Belinda , Pritchard Michele , Sykes April , Lu Zhaohua , Wendler Dave , Baker Justin N. 
Published: January 2019

BackgroundHigh‐quality oncology care is marked by skillful communication, yet little is known about patient and family communication perceptions or content preferences. Our study sought to elicit pediatric oncology patient and parent perceptions of early cancer communication to establish whether informational needs were met and identify opportunities for enhanced communication throughout cancer care.MethodAn original survey instrument was developed, pretested, and administered to 129 patients, age 10‐18 years, and their parents at 3 cancer centers between 2011 and 2015. Statistical analysis of survey items about perceived communication, related associations, and patient/parent concordance was performed.ResultsA greater percentage of participants reported “a lot” of discussion about the physical impact of cancer (patients, 58.1% [n = 75]; parents, 69.8% [n = 90]) compared with impact on quality of life (QOL) (patients, 44.2% [n = 57]; parents, 55.8% [n = 72]) or emotional impact (patients, 31.8% [n = 41]; parents, 43.4% [n = 56]). One fifth of patients (20.9% [n = 27]) reported they had no up‐front discussion about the emotional impact of cancer treatment. Parents indicated a desire for increased discussion regarding impact on family life (27.9% [n = 36]), long‐term QOL (27.9% [n = 36]), and daily activities (20.2% [n = 26]). Patients more frequently than parents indicated a desire for increased physician/patient discussion around the impact on daily activities (patients, 40.3% [n = 52]; parents, 21.7% [n = 28]; P < .001), long‐term QOL (patients, 34.9% [n = 45]; parents, 16.3% [n = 21]; P < .001), pain management (patients, 23.3% [n = 30]; parents, 7% [n = 9]; P < .001), physical symptom management (patients, 24% [n = 31]; parents, 7.8% [n = 10]; P < .001), short‐term QOL (patients, 23.3% [n = 30]; parents, 9.3% [n = 12]; P = .001), and curative potential (patients, 21.7% [n = 28]; parents, 8.5% [n = 11]; P = .002, P values calculated using McNemar’s test).ConclusionOncologists may not be meeting the informational needs of many patients and some parents/caregivers. Communication could be enhanced through increased direct physician–patient communication, as well as proactive discussion of emotional symptoms and impact of cancer on QOL.
Proton Relaxometry of Long‐Lived Spin Order
Authors: Kiryutin Alexey S. , Panov Mikhail S. , Yurkovskaya Alexandra V. , Ivanov Konstantin L. , Bodenhausen Geoffrey 
Published: January 2019

AbstractA study of long‐lived spin order in chlorothiophene carboxylates at both high and low magnetic fields is presented. Careful sample preparation (removal of dissolved oxygen in solution, chelating of paramagnetic impurities, reduction of convection) allows one to obtain very long‐lived singlet order of the two coupled protons in chlorothiophene derivatives, having lifetimes of about 130 s in D2O and 240 s in deuterated methanol, which are much longer than the T1‐relaxation times (18 and 30 s, respectively, at a field
=9.4 T). In protonated solvents the relaxation times become shorter, but the lifetime is still substantially longer than
. In addition, long‐lived coherences are shown to have lifetimes as long as 30 s. Thiophene derivatives can be used as molecular tags to study slow transport, slow dynamics and slow chemical processes, as has been shown in recent years.
Computational Electrochemistry of Water Oxidation on Metal‐Doped and Metal‐Supported Defective h‐BN
Authors: Perilli Daniele , Selli Daniele , Liu Hongsheng , Di Valentin Cristiana 
Published: January 2019

AbstractMetal‐doped and metal‐supported two‐dimensional materials are attracting a lot of interest as potentially active electrocatalysts for reduction and oxidation processes. Previously, when a non‐regular 2 D h‐BN layer was grown on a Cu(111) surface, metal adatoms were found to spontaneously emerge from the bulk to fill the atomic holes in the structure and become available for surface catalysis. Herein, computational electrochemistry is used to investigate and compare the performance of Cu‐doped and Cu‐supported pristine and defective h‐BN systems for the electrocatalytic water oxidation reaction. For the various model systems, the intermediate species of this multistep oxidation process are identified and the free‐energy variations for each step of reaction are computed, even for those steps that do not involve an electron or a proton transfer. Both associative and O2 direct evolution mechanisms are considered. On this thermodynamic basis, the potential‐determining step, the thermodynamic‐determining step, and consequently the theoretical overpotential are determined for comparison with experiments. Small Cu clusters (tetramers) trapped in the h‐BN defective lattice on a Cu(111) support are found to be very active for the water oxidation reaction since such systems are characterized by a low overpotential and by a small energy cost for O2 release from the catalyst, which is often observed to be a major limit for other potential electrocatalysts.
Pyridinic Nitrogen‐Doped Graphene Nanoshells Boost the Catalytic Efficiency of Palladium Nanoparticles for the N‐Allylation Reaction
Authors: Li Xinxin , Zhao Qingshan , Feng Xiang , Pan Lei , Wu Zhuangzhuang , Wu Xiaocui , Ma Tianwen , Liu Jialiang , Pan Yuanyuan , Song Yan , Wu Mingbo 
Published: January 2019

AbstractIn this study, nitrogen‐doped graphene nanoshells (N‐GNS) were developed to support palladium nanoparticles (Pd/N‐GNS) as an efficient and recyclable catalyst for the N‐allylation reaction. N‐GNS was synthesized through a facile hard‐template method by using petroleum asphalt, followed by nitrogen doping by thermal annealing with urea, the contents and species of which could be altered by the calcination temperature. Palladium nanoparticles (Pd NPs) with an average diameter of 3.3 nm were homogeneously deposited onto the N‐GNS support through a mild solvent‐growth approach. The Pd/N‐GNS exhibited a superior activity towards the N‐allylation reaction, 6‐fold higher than that of the pristine graphene nanoshells supporting the palladium catalyst. The Pd/N‐GNS could be recycled several times without activity deterioration and metal leaching. The catalytic activity showed a linear correlation relationship with the pyridinic N content. Experimental and theoretical studies reveal strong metal–support interactions between the pyridinic N and palladium species, which can downsize the Pd NPs, modulate the electronic properties, and promote the adsorption of reactant, thereby significantly boosting the catalytic efficiency and stability for the N‐allylation process. The present work could help unravel the roles of nitrogen‐doped carbon supports and provides a feasible strategy to rationally design superior palladium catalysts for chemical transformations.
Scaling Up Electrodes for Photoelectrochemical Water Splitting: Fabrication Process and Performance of 40 cm2LaTiO2N Photoanodes
Authors: Dilger Stefan , Trottmann Matthias , Pokrant Simone 
Published: January 2019

AbstractA scalable process for fabrication of particle‐based photoanodes is developed. The electrodes are versatilely made of photocatalytically active semiconductor particles, in this case LaTiO2N, and optionally coated with cocatalysts and protecting components, all immobilized on a conducting substrate. The involved fabrication steps are restricted to scalable processes such as electrophoretic deposition, annealing in air, and dip coating. Special care is taken to ensure efficient charge transport in‐between particles and to the substrate by incorporating conducting connectors. By adapting the fabrication steps, the electrode geometrical dimension is increased from the size of a typical lab electrode of 1 to 40 cm2. The quality of the scale‐up process is characterized by comparing the photoanodes in terms of thickness, light‐absorption properties, and morphology. For several compositions, the electrochemical performance of both electrode sizes is assessed by measuring the photocurrents and faradaic efficiencies. The comparison revealed a complex upscaling behavior and showed that the photoelectrode size affects performance already on the 0.1 m scale.
Predictive value of the anal cytology for detecting anal intraepithelial neoplasia or worse: A systematic review and meta‐analysis
Authors: Chen Cheng‐Chieh , Chou Yuh‐Yu 
Published: January 2019

BackgroundAnal intraepithelial neoplasia (AIN) refers to a precancerous lesion of anal squamous cell carcinoma (SCC). Human papillomavirus (HPV) is considered a crucial risk factor for AIN. Individuals with high‐risk sexual behaviour, such as receptive anal intercourse and multiple sexual partners, as well as men who have sex with men exhibit a relatively high rate of AIN. The anal cytology is a screening method for AIN in high‐risk individuals, and patients with abnormal anal cytology may benefit from high‐resolution anoscopy. This study explored the predictive value of the anal cytology for the detection of AIN or worse (AIN+).MethodsWe searched the databases of PubMed, BioMed Central, Cochrane Library, and Google Scholar for relevant studies. Studies on the diagnostic efficacy of the anal cytology for predicting anal cancer on a per‐patient basis were included. We excluded review articles. Either prospective trials or retrospective studies were included. We performed the meta‐analysis by using a random‐effects model to generate a pooled sensitivity, specificity, and diagnostic odds ratio (DOR). All analyses were performed using the MetaDiSc version 1.4 software (Universidad Complutense, Madrid, Spain).ResultsTwelve studies with 2541 participants were retrieved. The meta‐analysis of the studies assessing the predictive value of the anal cytology for detecting AIN+ generated a pooled sensitivity of 0.79 (95% confidence interval [CI], 0.77‐0.82) and a pooled specificity of 0.66 (95% CI, 0.64‐0.69). The pooled DOR for the anal cytology was 5.31 (95% CI, 3.31‐8.49).ConclusionsOur results revealed that the anal cytology might be effective in diagnosing AIN+.
Sex‐biased survival contributes to population decline in a long‐lived seabird, the Magellanic Penguin
Authors: Gownaris N. J. , Boersma P. D. 
Published: January 2019

AbstractWe developed a Hidden Markov mark–recapture model (R package marked) to examine sex‐specific demography in Magellanic Penguins (Spheniscus magellanicus). Our model was based on 33 yr of resightings at Punta Tombo, Argentina, where we banded ~44,000 chicks from 1983 to 2010. Because we sexed only 57% of individuals over their lifetime, we treated sex as an uncertain state in our model. Our goals were to provide insight into the population dynamics of this declining colony, to inform conservation of this species, and to highlight the importance of considering sex‐specific vital rates in demographic seabird studies. Like many other seabirds, Magellanic Penguins are long‐lived, serially monogamous, and exhibit obligate biparental care. We found that the non‐breeding‐season survival of females was lower than that of males and that the magnitude of this bias was highest for juveniles. Biases in survival accumulated as cohorts aged, leading to increasingly skewed sex ratios. The survival bias was greatest in years when overall survival was low, that is, females fared disproportionality worse when conditions were unfavorable. Our model‐estimated survival patterns are consistent with independent data on carcasses from the species’ non‐breeding grounds, showing that mortality is higher for juveniles than for adults and higher for females than for males. Juveniles may be less efficient foragers than adults are and, because of their smaller size, females may show less resilience to food scarcity than males. We used perturbation analysis of a population matrix model to determine the impact of sex‐biased survival on adult sex ratio and population growth rate at Punta Tombo. We found that adult sex ratio and population growth rate have the greatest proportional response, that is, elasticity, to female pre‐breeder and adult survival. Sex bias in juvenile survival (i.e., lower survival of females) made the greatest contribution to population declines from 1990 to 2009. Because starvation is a leading cause of morality in juveniles and adults, precautionary fisheries and spatial management in the region could help to slow population decline. Our data add to growing evidence that knowledge of sex‐specific demography and sex ratios are necessary for accurate assessment of seabird population trends.
Contrasting nitrogen fluxes in African tropical forests of the Congo Basin
Authors: Bauters Marijn , Verbeeck Hans , Rütting Tobias , Barthel Matti , Bazirake Mujinya Basile , Bamba Fernando , Bodé Samuel , Boyemba Faustin , Bulonza Emmanuel , Carlsson Elin , Eriksson Linnéa , Makelele Isaac , Six Johan , Cizungu Ntaboba Landry , Boeckx Pascal 
Published: January 2019

AbstractThe observation of high losses of bioavailable nitrogen (N) and N richness in tropical forests is paradoxical with an apparent lack of N input. Hence, the current concept asserts that biological nitrogen fixation (BNF) must be a major N input for tropical forests. However, well‐characterized N cycles are rare and geographically biased; organic N compounds are often neglected and soil gross N cycling is not well quantified. We conducted comprehensive N input and output measurements in four tropical forest types of the Congo Basin with contrasting biotic (mycorrhizal association) and abiotic (lowland–highland) environments. In 12 standardized setups, we monitored N deposition, throughfall, litterfall, leaching, and export during one hydrological year and completed this empirical N budget with nitrous oxide (N2O) flux measurement campaigns in both wet and dry season and in situ gross soil N transformations using15N‐tracing and numerical modeling. We found that all forests showed a very tight soil N cycle, with gross mineralization to immobilization ratios (M/I) close to 1 and relatively low gross nitrification to mineralization ratios (N/M). This was in line with the observation of dissolved organic nitrogen (DON) dominating N losses for the most abundant, arbuscular mycorrhizal associated, lowland forest type, but in contrast with high losses of dissolved inorganic nitrogen (DIN) in all other forest types. Altogether, our observations show that different forest types in central Africa exhibit N fluxes of contrasting magnitudes and N‐species composition. In contrast to many Neotropical forests, our estimated N budgets of central African forests are imbalanced by a higher N input than output, with organic N contributing significantly to the input‐output balance. This suggests that important other losses that are unaccounted for (e.g.,NOxand N2as well as particulate N) might play a major role in the N cycle of mature African tropical forests.
Quantifying specialist avifaunal decline in grassland birds of the Northern Great Plains
Authors: Correll Maureen D. , Strasser Erin H. , Green Adam W. , Panjabi Arvind O. 
Published: January 2019

AbstractHabitat specialists are declining worldwide, often paralleling rapid loss of habitat. Grassland habitats across North America are declining precipitously, due in part to intense conversion of grasslands to agriculture and rangelands, and specialist communities reliant upon this landscape are at particular risk of decline and collapse. We explored the relationship between grassland habitat specialism in birds and species population trends using several different grassland specialism indices (GSIs). Our data sources for these indices included (1) a regional bird dataset employing a spatially stratified sampling design (Integrated Monitoring of Bird Conservation Regions) of bird surveys in the Northern Great Plains of North America, and (2) geospatial data of species ranges (BirdLife Int'l) and grassland habitat (CEC North American Land Cover). We found a negative relationship between degree of habitat specialism and species population trends for all specialism metrics. We also found some evidence to support that specialism to grasslands on the wintering grounds partially explains population trends during the breeding season, giving added weight to the consideration of habitat conservation across the full annual cycle of a species to reverse or lessen population decline. Our work is the first to use quantitative methods to confirm the precarious state of grassland specialist songbirds in North America as well as demonstrate multiple methods for quantifying habitat specialism across different types of datasets.