bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gap measurements via low‐loss
EELS
on atomically thin
M
ox
W
(1‐x)
S
2 nanoflakes
Authors: Pelaez Fernandez Mario , Suenaga Kazu , Arenal Raul 
Published: December 2016

The properties of alloyed materials are a fundamental issue in Materials Science. For years, layered semiconductors of the TX
2
type (T=Mo, W; X=S, Se, Te) have been the subject of a varied range of studies due to their interesting electric, optical, catalytic and structural properties. In this sense, Mo
x
W
(1‐x)
S
2
alloys have been recently reported [1,2]; but most of their properties haven't been delved into yet. In this contribution, we focus on the local optoelectronic properties of such atomically thin (up to 6‐8 layers) of Mo
x
W
(1‐x)
S
2
. These properties have been probed by low‐loss EELS measurements [3] and we have examined the bandgap behavior for different alloying degrees of such nanomaterials as well as a function of the number of layers.

These works have been carried out using a FEI Titan Cs probe‐corrected microscope equipped with a monochromator (working at 80 KV and with an energy resolution of ~180 meV).

Figure 1 displays three HRSTEM‐HAADF micrographs of three different monolayers of MoS
2,
Mo
0.5
W
0.5
S
2
and WS
2
samples, respectively. The alloying effects of such materials can be easily distinguished from the HAADF image corresponding to the Mo
0.5
W
0.5
S
2
sample (Fig. 1(a) second image from the left). The areas of reduced number of layers have been selected via optical and low‐magnification TEM images and identified for the low‐loss measurements, see Fig. 1(b).

Low‐loss EEL spectra, using the spectrum‐line mode, have been recorded in regions where different stacks of a few layers can be noticed, see Fig. 2. In each of these stacks, easily recognisable for being the flat regions in the HAADF intensity profile (Figure 2(b)), several spectra have been integrated over a window of 10 to 12 nm. After zero loss peak (ZLP) extraction, the different spectra are fitted to obtain the band‐gap value in each of these zones. In parallel, the thickness of these areas has been estimated, using the standard procedure [4]. Finally, these results show a relation between the band‐gap of the material and the number of layers for every composition (Figure 2(c)).
All these results will be deeply discussed in the framework of previous experimental (photoluminescence) and theoretical (DFT calculations) works carried out in these material [1,2]. In conclusion, the present studies improve our knowledge of the optoelectronic properties of atomically thin layered alloys of dichalcogenides and provides further insight into the potential applications of these materials.
Surface effects in nano‐cobalt ferrites
Authors: Saidani Mohamed , Belkacem Wajdi , Patout Loïc , Charai Ahmed , Mliki Najeh 
Published: December 2016

Magnetic nanoparticles have been the issue of continuous and growing interest, from both fundamental and technological points of view, in the last decades. Their unique physical objects with remarkable magnetic properties differ significantly from their parent massive materials. These properties are due to finite size effects of the magnetic core, related to the reduced number of spins cooperatively linked within the particle, and to surface and interface effects, related to the lack of coordination for the surface ions, inducing broken exchange bonds that can result in frustration and spin disorder. A description of ferrite magnetic properties requires a through characterization of the crystallographic structure down to atomic scale. Indeed, synthesis processes significantly alter the chemistry of the involved compounds, and then their physical properties.
In this work, experimental investigations on cobalt ferrite nanoparticles CoxFe3‐xO4 (1 < x < 1.8) are reported, providing a comprehensive description of different surface and interface effects. Surface and exchange anisotropy in ferrite nanoparticles are investigated by means of several experimental techniques such as X ray diffraction, Transmission Electron Microscopy and magnetization measurements. A strong correlation between the structural and the magnetic properties has been revealed. It is shown that the proposed synthesis technique leads to the formation of a spinel nanoparticles well dispersed. Many of them are faceted having cub‐octahedral polygonal growth forms with exclusively the {1 1 1} and {1 0 0} type faces. Rather than core‐shell structures, a number of ordered defects were observed.
Nanotomy and
CLEM
techniques shed new light on biomedical processes
Authors: Giepmans Ben 
Published: December 2016

A spectrum of dyes and probes now enable to localize molecules of interest within living cells by fluorescence microscopy. With electron microscopy (EM), cellular ultrastructure has been revealed. Bridging these two modalities, correlated light microscopy and EM (CLEM) opens new avenues [1].
The first focus will be on recent developed labeling strategies for molecules that allow CLEM (Fig.1). These include particles and substrates to highlight endogenous proteins that are targeted using affinity, but also genetically‐encoded probes [2], and traditional stains for light microscopy that aid in EM‐analysis of samples. Probes that can only be detected in a single modality, and require image overlay, as well as combinatorial probes that can be visualized both at LM and EM levels will be discussed.

In addition, new approaches for large scale EM (“nanotomy”), either TEM‐based [3] or S(T)EM‐based [4,5], to visualize macromolecules and organelles in the context of organized cell systems and tissues will be highlighted. Matching the areas of acquisition in CLEM and EM will not only increase understanding of the molecules in the context, but also is a straight forward manner to combine the LM and EM image data. While these new developments aid to better understand the contribution of molecules, organelles and cells in tissue‐function, the amount of data is huge and quantification and sharing data need new solutions. We will show how millions of particles can be recognized and quantified using Fiji. Moreover, our open‐access data‐sharing (Fig.2) via
nanotomy.org
will be highlighted to easily access the ultrastructure in a variety of research projects, including blistering diseases that affect skin and mucosa in men and Type 1 diabetes.

Covering a variety of probes and approaches for image overlay will help to enable (new) users to broadly implement CLEM and/or nanotomy to better understand how molecules (mal)function in biology [6].
Durch sichtbares Licht vermittelte Funktionalisierungen von Benzotriazolen, inspiriert durch mechanismusbasiertes Lumineszenz‐ Screening
Authors: Teders Michael , Gómez‐Suárez Adrián , Pitzer Lena , Hopkinson Matthew N. , Glorius Frank 
Published: December 2016

AbstractDrei neuartige, durch sichtbares Licht vermittelte Funktionalisierungen von Benzotriazolen als Quencher‐Substratklasse, entdeckt mithilfe einer mechanismusbasierten Screening‐Methode, wurden entwickelt. Mit dieser Synthesestrategie wurden unter milden Bedingungen ortho‐thiolierte, borylierte und alkylierte N‐Arylbenzamide erhalten. Die Verträglichkeit der Borylierungsreaktion mit funktionellen Gruppen wurde durch die erste Anwendung eines additivbasierten Robustheits‐Screens einer photokatalytischen Transformation untersucht. Allen Funktionalisierungen liegen photokatalytisch initiierte Kettenmechanismen zugrunde, wie durch die Bestimmung der Reaktionsquantenausbeute und durch Stern‐Volmer‐Analysen ermittelt werden konnte.
Constructing Hierarchical Tectorum‐like α‐Fe2O3/PPy Nanoarrays on Carbon Cloth for Solid‐State Asymmetric Supercapacitors
Authors: Wang Libin , Yang Huiling , Liu Xiaoxiao , Zeng Rui , Li Ming , Huang Yunhui , Hu Xianluo 
Published: December 2016

AbstractThe design of complex heterostructured electrode materials that deliver superior electrochemical performances to their individual counterparts has stimulated intensive research on configuring supercapacitors with high energy and power densities. Herein we fabricate hierarchical tectorum‐like α‐Fe2O3/polypyrrole (PPy) nanoarrays (T‐Fe2O3/PPy NAs). The 3D, and interconnected T‐Fe2O3/PPy NAs are successfully grown on conductive carbon cloth through an easy self‐sacrificing template and in situ vapor‐phase polymerization route under mild conditions. The electrode made of the T‐Fe2O3/PPy NAs exhibits a high areal capacitance of 382.4 mF cm−2 at a current density of 0.5 mA cm−2 and excellent reversibility. The solid‐state asymmetric supercapacitor consisting of T‐Fe2O3/PPy NAs and MnO2 electrodes achieves a high energy density of 0.22 mWh cm−3 at a power density of 165.6 mW cm−3.
Eine Conia‐En‐artige Cyclisierung unter basischen Bedingungen ermöglicht die effiziente Synthese von (−)‐Lycoposerramin R
Authors: Hartrampf Felix W. W. , Furukawa Takayuki , Trauner Dirk 
Published: December 2016

AbstractEine enantioselektive Synthese des Lycopodium‐Alkaloids Lycoposerramin R wird vorgestellt. Diese basiert auf einer basenvermittelten Cyclisierung, welche der Conia‐En‐Reaktion und ihren goldkatalysierten Varianten ähnelt. Mittels dieser Methode können Hydrindanone und andere mit einer exo‐Methylengruppe funktionalisierte Ringsysteme bei Raumtemperatur ohne Metallkatalyse oder Substrataktivierung erhalten werden.
Kombination von Cp*RhIII‐katalysierter C‐H‐Aktivierung mit einer Variante der Wagner‐Meerwein‐Umlagerung
Authors: Wang Xiaoming , Lerchen Andreas , Gensch Tobias , Knecht Tobias , Daniliuc Constantin G. , Glorius Frank 
Published: December 2016

AbstractEine Kombination aus Cp*RhIII‐katalysierter C‐H‐Aktivierung und einer Variante der Wagner‐Meerwein‐Umlagerung wurde zum ersten Mal erfolgreich realisiert. Hierbei konnten verbrückte polycyclische Moleküle, die über andere Methoden nicht einfach zu erhalten sind, unter milden Bedingungen mit einer hohen Effizienz (0.5 Mol‐% Rh‐Katalysator) durch die Kupplung von N‐Phenoxyacetamiden mit 7‐Azabenzonorbornadienen synthetisiert werden.
In‐Cell Activation of Organo‐Osmium(II) Anticancer Complexes
Authors: Needham Russell J. , Sanchez‐Cano Carlos , Zhang Xin , Romero‐Canelón Isolda , Habtemariam Abraha , Cooper Margaret S. , Meszaros Levente , Clarkson Guy J. , Blower Philip J. , Sadler Peter J. 
Published: December 2016

AbstractThe family of iodido OsII arene phenylazopyridine complexes [Os(η6‐p‐cym)(5‐R1‐pyridylazo‐4‐R2‐phenyl))I]+ (where p‐cym=para‐cymene) exhibit potent sub‐micromolar antiproliferative activity towards human cancer cells and are active in vivo. Their chemical behavior is distinct from that of cisplatin: they do not readily hydrolyze, nor bind to DNA bases. We report here a mechanism by which they are activated in cancer cells, involving release of the I− ligand in the presence of glutathione (GSH). The X‐ray crystal structures of two active complexes are reported, 1‐I (R1=OEt, R2=H) and 2‐I (R1=H, R2=NMe2). They were labelled with the radionuclide 131I (β−/γ emitter, t1/2 8.02 d), and their activity in MCF‐7 human breast cancer cells was studied. 1‐[131I] and 2‐[131I] exhibit good stability in both phosphate‐buffered saline and blood serum. In contrast, once taken up by MCF‐7 cells, the iodide ligand is rapidly pumped out. Intriguingly, GSH catalyzes their hydrolysis. The resulting hydroxido complexes can form thiolato and sulfenato adducts with GSH, and react with H2O2 generating hydroxyl radicals. These findings shed new light on the mechanism of action of these organo‐osmium complexes.
C−H and C−N Activation at Redox‐Active Pyridine Complexes of Iron
Authors: MacLeod K. Cory , Lewis Richard A. , DeRosha Daniel E. , Mercado Brandon Q. , Holland Patrick L. 
Published: December 2016

AbstractPyridine activation by inexpensive iron catalysts has great utility, but the steps through which iron species can break the strong (105–111 kcal mol−1) C−H bonds of pyridine substrates are unknown. In this work, we report the rapid room‐temperature cleavage of C−H bonds in pyridine, 4‐tert‐butylpyridine, and 2‐phenylpyridine by an iron(I) species, to give well‐characterized iron(II) products. In addition, 4‐dimethylaminopyridine (DMAP) undergoes room‐temperature C−N bond cleavage, which forms a dimethylamidoiron(II) complex and a pyridyl‐bridged tetrairon(II) square. These facile bond‐cleaving reactions are proposed to occur through intermediates having a two‐electron reduced pyridine that bridges two iron centers. Thus, the redox non‐innocence of the pyridine can play a key role in enabling high regioselectivity for difficult reactions.
Diverse Visible‐Light‐Promoted Functionalizations of Benzotriazoles Inspired by Mechanism‐Based Luminescence Screening
Authors: Teders Michael , Gómez‐Suárez Adrián , Pitzer Lena , Hopkinson Matthew N. , Glorius Frank 
Published: December 2016

AbstractThree new visible‐light‐promoted functionalizations of benzotriazole substrates were discovered using a mechanism‐based screening method. ortho‐Thiolated, borylated, and alkylated N‐arylbenzamide products were obtained under mild reaction conditions in a new denitrogenative synthetic approach to functionalized aniline derivatives. The functional group tolerance of the borylation reaction was further analyzed in the first application of an additive‐based robustness screen in a photocatalytic transformation. All the functionalizations proceed via photocatalytically initiated chain mechanisms as indicated by determination of the reaction quantum yields and Stern–Volmer analyses.
A Conia‐Ene‐Type Cyclization under Basic Conditions Enables an Efficient Synthesis of (−)‐Lycoposerramine R
Authors: Hartrampf Felix W. W. , Furukawa Takayuki , Trauner Dirk 
Published: December 2016

AbstractAn enantioselective total synthesis of the Lycopodium alkaloid lycoposerramine R is presented. It relies on a base‐mediated cyclization that resembles the Conia‐ene reaction of ynones and gold‐catalyzed variants thereof. Thus, hydrindanones and other functionalized ring systems bearing an exocyclic alkene can be rapidly accessed at room temperature without noble metal catalysis or substrate preactivation.
Combination of Cp*RhIII‐Catalyzed C−H Activation and a Wagner–Meerwein‐Type Rearrangement
Authors: Wang Xiaoming , Lerchen Andreas , Gensch Tobias , Knecht Tobias , Daniliuc Constantin G. , Glorius Frank 
Published: December 2016

AbstractA combination of Cp*RhIII‐catalyzed C−H activation and Wagner–Meerwein‐type rearrangement was successfully achieved for the first time. Thus, bridged polycyclic molecules that are not readily accessible by other means were accessed under mild conditions with high efficiency (as low as 0.5 mol % Rh catalyst) in the coupling of N‐phenoxyacetamide with 7‐azabenzonorbornadiene.
Halogen‐Bonded Supramolecular Capsules in the Solid State, in Solution, and in the Gas Phase
Authors: Dumele Oliver , Schreib Benedikt , Warzok Ulrike , Trapp Nils , Schalley Christoph A. , Diederich François 
Published: December 2016

AbstractSupramolecular capsules were assembled by neutral halogen bonding (XB) and studied in the solid state, in solution, and in the gas phase. The geometry of the highly organized capsules is shown by an X‐ray crystal structure which features the assembly of two XB hemispheres, geometrically rigidified by H‐bonding to eight MeOH molecules and encapsulation of two benzene guests. To enhance capsular association strength, tuning the XB donor is more efficient than tuning the XB acceptor, due to desolvation penalties in protic solvents, as shown for a tetraquinuclidine XB acceptor hemisphere. With a tetra(iodoethynyl) XB donor and a tetralutidine XB acceptor, the association in deuterated benzene/acetone/methanol 70:30:1 at 283 K reaches Ka=(2.11±0.39)×105 m−1 (ΔG=−6.9±0.1 kcal mol−1). The stability of the XB capsules in the gas phase was confirmed by electrospray ionization mass spectrometry (ESI‐MS). A new guest binding site was uncovered within the elongated iodoethynyl capsule.
Environment‐Related Variation in the Human Mid‐Face
Authors: Cui Yaming , Leclercq Sébastien 
Published: December 2016

ABSTRACTPrevious studies that have examined mid‐facial morphology in geographically dispersed and genetically diverse groups of humans have shown a strong adaptation of the nasal part to extreme cold environments, which was not observed in non‐Arctic regions. However, it remains unclear whether different parts of the mid‐face area show independent adaptation to nonpolar climates, and if so, how this adaptation impacted the morphology. To address this question, we investigated potential associations between climatic variables and the mid‐facial shape in 14 populations, focusing on four aspects of the morphology: total shape, zygomatic, nasal and alveolar. The results show that when the genetic distance between populations is not considered, all aspects of the morphology are strongly correlated with all climatic variables. When the genetic distance is considered, significant correlations remain only for the zygomatic, and nasal parts with temperature, and for the nasal part and alveolar with sunshine exposure. A strong but probably artificial correlation of the alveolar with atmospheric pressure is also observed. Additionally, partial least square analyses indicate that tropical and subtropical environments are associated with smaller zygomatic and more triangular nose aperture compared to more temperate environments. These findings suggest that temperate and tropical climates have induced adaptation of zygomatic and nasal parts of the mid‐face in humans, and that this adaptation was probably driven by temperature and sunlight exposure conditions. Anat Rec, 300:238–250, 2017. © 2016 Wiley Periodicals, Inc.
Toward Understanding the Mammalian Zygoma: Insights From Comparative Anatomy, Growth and Development, and Morphometric Analysis
Authors: Márquez Samuel , Pagano Anthony S. , Schwartz Jeffrey H. , Curtis Abigail , Delman Bradley N. , Lawson William , Laitman Jeffrey T. 
Published: December 2016

ABSTRACTThe zygoma, or jugum, is a cranial element that was present in Mesozoic tetrapods, well before the appearance of mammals. Although as an entity the zygoma is a primitive retention among mammals, it has assumed myriad configurations as this group diversified. As the zygoma is located at the intersection of the visual, respiratory, and masticatory apparatuses, it is potentially of great importance in systematic, phylogenetic, and functional studies focused on this region. For example, the facial component of the zygoma and its contribution to a postorbital bar (POB) appear to be relevant to the systematics of a number of mammalian subclades, and the formation of a bony postorbital septum (POS) that separates the orbit from the infratemporal fossa is unique to, and thus potentially phylogenetically significant for uniting anthropoid primates, while the zygoma itself appears to serve to resist tension and bending forces during mastication. In order to better understand the zygoma in the context of its contributions to the circumorbital region, we documented its morphological expression in specimens representing 10 orders of mammals. Since the presence of a POB and of a POS has long been used to justify uniting extant primates and anthropoid primates as respective clades, and because postorbital closure (POC) is morphologically more complex than a POB, we provide detail necessary to address these claims. Our taxically broad overview also allowed us to provide for the first time definitions of configurations that can be applied to future studies. Using a different, but also taxically broad sample of mammals, and of primates in particular, we performed two geometric morphometric analyses that were geared toward testing long‐held interpretations of the functional role of the zygoma, especially with regard to mastication and in the context of orbital frontation (to which the zygoma contributes). Further, overall, zygomatic morphology tends not to scale with allometry, sexual dimorphism, or angle of orbital convergence, but it does contribute to unique patterns of intraspecies variation. Anat Rec, 300:76–151, 2017. © 2016 Wiley Periodicals, Inc.
Morphological Diversity and Evolution of the Jugal in Dinosaurs
Authors: Sullivan Corwin , Xu Xing 
Published: December 2016

ABSTRACTIn dinosaurs, as in other reptiles, the homologue of the mammalian zygomatic bone is the jugal. The dinosaurian jugal was primitively triradiate, with posterior, dorsal and anterior processes that respectively contacted the quadratojugal, the postorbital, and the maxilla and lacrimal. However, the jugal evolved along different lines in the three major dinosaurian clades. In theropods this cranial element remained relatively conservative in morphology, apart from being reduced to a rod‐like structure in most birds and a few non‐avians. In sauropodomorphs the jugal eventually became small, plate‐like and nearly restricted to the area below the orbit, even being excluded from the ventral margin of the skull in many derived taxa. Among ornithischians the jugal was highly variable, but in many cases became large and/or adorned with ornamental features such as horns, flanges, and rugosities. The jugal does not appear to have been a site of muscle attachment in most non‐avian dinosaurs, but represented an important structural element in the akinetic dinosaurian skull. The conspicuous jugal ornaments seen in many ornithischian dinosaurs, like the less striking ones documented in some saurischians, may have played an important role in the social behavior of the species that possessed them. In many cases they have a weapon‐like aspect suggesting use in aggressive displays, if not actual combat, adding to the evidence that agonistic behavior was likely widespread among ornithischians in particular. Anat Rec, 300:30–48, 2017. © 2016 Wiley Periodicals, Inc.
Zygomatic Root Position in Recent and Fossil Hominids
Authors: Weber Gerhard W. , Krenn Viktoria A. 
Published: December 2016

ABSTRACTThe relative position of the zygomatic root to the dentition plays a crucial role in determining the overall strength of the face in response to bite forces. The powerful superficial head of the masseter arises there and the zygomaticoalveolar crest (ZAC) is discussed as a buttressing feature of the face. For instance, a more forwardly or backwardly positioned zygomatic root or a lower or higher vertical distance to the dentition could be indicative for evolutionary adaptations to particular loading regimes which are associated with diet. We therefore examined the morphology of the maxilla using state‐of‐the‐art 3D Geometric Morphometric methods. The data set was reduced to a minimum of relevant measurements and includes five landmarks (pr, ol, zm, lingual and buccal midpoint of second molar alveoli) and three curves with semilandmarks along the lingual and buccal alveolar rim and the ZAC. Results show a stunning overlap in shape variation. We find no clear pattern of shape that would allow separating different hominid groups with confidence, except two extreme forms—Paranthropines and Neanderthals. We also find no clear trend over time. Australopithecines, Habilines, Erectines, and Middle Pleistocene Homo can be very similar to modern humans. Even great apes are within or not far from the central shape distribution of Homo, but they separate clearly from gracile and robust Australopithecines. We discuss the shape factors underlying our data. The geometry studied allows simple measurements and analyses and is thus potentially interesting for classification purposes of extreme forms. Anat Rec, 300:160–170, 2017. © 2016 Wiley Periodicals, Inc.