Comparative architecture of the tessellated boxfish (Ostracioidea) carapace.

Tessellations (surface architectures of arrays of hard tiles) are common in natural and man-made designs. Boxfishes (Ostracioidea) are almost completely encased in a tessellated armor and have evolved a plethora of cross-sectional carapace shapes, yet whether the scutes constructing these exhibit comparable variation is unknown. Using high-resolution microCT and semi-automatic segmentation algorithms, we quantitatively examined thousands of scutes from 13 species of diverse body form.

Synthesis and Structures of Oxide -Centred Alkali Metal (K, Li)/Lanthanoid (Ln3 or 4) 3,5-Dimethylpyrazolate Cages - Herbert Schumann Revisited.

Reaction of lanthanoid tris(3,5-dimethylpyrazolate) compounds, [Ln(Mepz)(thf)] (Ln=La 1 a, Ce, Pr, Dy 1 b, Yb, Lu) with potassium or lithium bistrimethylsilylamide and with or without added 3,5-dimethylpyrazole, or of lanthanoid tris(bistrimethylsilyl)amide complexes with potassium bistrimethylsilylamide and 3,5-dimethylpyrazole have yielded a variety of oxide centred Ln or Ln/(K or Li) multinuclear cages, namely, [LaO(Mepz) K(thf)] (2 a), [LaO(Mepz)Li(MepzH)]⋅0.5Hexane (2 b), [LaO(Mepz)(MepzH)] (2 c) (from heating 1 a in toluene), [CeO(Mepz)K(dme)] (3 a), [CeO(Mepz)Li(thf)]⋅0.5Hexane (3 b) and [Ce(Mepz)Li(thf)] (3 c), which crystallized together, [CeO(Mepz)K(thf)] (3 d), [PrO(Mepz)K(thf)] (4), [DyO(Mepz)K(thf)]⋅THF (5), [YbO(Mepz)K(thf)]⋅THF (6), and [LuO(Mepz)K(thf)]⋅THF (7).

Numerically Exact Simulation of Photodoped Mott Insulators.

A description of long-lived photodoped states in Mott insulators is challenging, as it needs to address exponentially separated timescales. We demonstrate how properties of such states can be computed using numerically exact steady state techniques, in particular, the quantum Monte Carlo algorithm, by using a time-local ansatz for the distribution function with separate Fermi functions for the electron and hole quasiparticles. The simulations show that the Mott gap remains robust to large photodoping, and the photodoped state has hole and electron quasiparticles with strongly renormalized properties.

Perylenetetracarboxylic Diimide Composite Electrodes as Organic Cathode Materials for Rechargeable Sodium-Ion Batteries: A Joint Experimental and Theoretical Study.

The organic semiconductor 3,4,9,10-perylenetetracarboxylic diimide (PTCDI), a widely used industrial pigment, has been identified as a diffusion-less Na-ion storage material, allowing for exceptionally fast charging/discharging rates. The elimination of diffusion effects in electrochemical measurements enables the assessment of interaction energies from simple cyclic voltammetry experiments through the theoretical work of Laviron and Tokuda. In this work, the two N-substituted perylenes, ,'-dimethyl-3,4,9,10-perylenetetracarboxylic diimide (MePTCDI) and ,'-diphenyl-3,4,9,10-perylenetetracarboxylic diimide (PhPTCDI), as well as the parent molecule 3,4,9,10-perylenetetracarboxylic diimide (HPTCDI) are investigated as thin-film composite electrodes on carbon fibers for sodium-ion batteries.

The complex structure of represents an architectural design for high-performance ultralightweight materials.

High strength, hardness, and fracture toughness are mechanical properties that are not commonly associated with the fleshy body of a fungus. Here, we show with detailed structural, chemical, and mechanical characterization that is an exception, and its architectural design is a source of inspiration for an emerging class of ultralightweight high-performance materials. Our findings reveal that .

The Influence of Human Factors Training in Air Rescue Service on Patient Safety in Hospitals: Results of an Online Survey.

: Air rescue crew members work equally in aviation and medicine, and thus occupy an important interface between the two work environments of aviation and medicine. The aim of this study was to obtain responses from participants to a validated online-based questionnaire regarding whether hospitals may benefit from the commitment of a medical hospital staff which is also professionally involved in the aviation system as emergency physicians and Helicopter Emergency Medical Services Technical Crew Members (HEMS TC). Furthermore, it focused on the question of whether the skills acquired through Crew Resource Management (CRM) training in the air rescue service might also be used in the ground-based rescue service and, if so, whether they may have a positive effect.

Titanium(IV) Surface Complexes Bearing Chelating Catecholato Ligands for Enhanced Band-Gap Reduction.

Protonolysis reactions between dimethylamido titanium(IV) catecholate [Ti(CAT)(NMe)] and neopentanol or tris(-butoxy)silanol gave catecholato-bridged dimers [(Ti(CAT)(OCHBu))(HNMe)] and [Ti(CAT){OSi(OBu)}(HNMe)], respectively. Analogous reactions using the dimeric dimethylamido titanium(IV) (3,6-di--butyl)catecholate [Ti(CATBu-3,6)(NMe)] yielded the monomeric Ti(CATBu-3,6)(OCHBu)(HNMe) and Ti(CATBu-3,6)[OSi(OBu)](HNMe). The neopentoxide complex Ti(CATBu-3,6)(OCHBu)(HNMe) engaged in further protonolysis reactions with Si-OH groups and was consequentially used for grafting onto mesoporous silica KIT-6.

Direct Electrochemical CO Capture Using Substituted Anthraquinones in Homogeneous Solutions: A Joint Experimental and Theoretical Study.

Electrochemical capture of carbon dioxide (CO) using organic quinones is a promising and intensively studied alternative to the industrially established scrubbing processes. While recent studies focused only on the influence of substituents having a simple mesomeric or nucleophilicity effect, we have systematically selected six anthraquinone (AQ) derivatives (X-AQ) with amino and hydroxy substituents in order to thoroughly study the influence thereof on the properties of electrochemical CO capture. Experimental data from cyclic voltammetry (CV) and UV-Vis spectroelectrochemistry of solutions in acetonitrile were analyzed and compared with innovative density functional tight binding computational results.

Anthraquinone and its derivatives as sustainable materials for electrochemical applications - a joint experimental and theoretical investigation of the redox potential in solution.

Anthraquinone (AQ) has long been identified as a highly promising lead structure for various applications in organic electronics. Considering the enormous number of possible substitution patterns of the AQ lead structure, with only a minority being commercially available, a systematic experimental screening of the associated electrochemical potentials represents a highly challenging and time consuming task, which can be greatly enhanced suitable virtual pre-screening techniques. In this work the calculated electrochemical reduction potentials of pristine AQ and 12 hydroxy- or/and amino-substituted AQ derivatives in ,-dimethylformamide have been correlated against newly measured experimental data.

Ontogeny of a tessellated surface: Carapace growth of the longhorn cowfish Lactoria cornuta.

Biological armors derive their mechanical integrity in part from their geometric architectures, often involving tessellations: individual structural elements tiled together to form surface shells. The carapace of boxfish, for example, is composed of mineralized polygonal plates, called scutes, arranged in a complex geometric pattern and nearly completely encasing the body. In contrast to artificial armors, the boxfish exoskeleton grows with the fish; the relationship between the tessellation and the gross structure of the armor is therefore critical to sustained protection throughout growth.

Beyond Takai's Olefination Reagent: Persistent Dehalogenation Emerges in a Chromium(III)-μ -Methylidyne Complex.

Reaction of CHI with six equivalents of CrCl in THF at low temperatures affords [Cr Cl (μ -Cl) (μ -CH)(thf) ] as the first isolable high-yield Cr μ -methylidyne complex. Substitution of the terminal chlorido ligands via salt metathesis with alkali-metal cyclopentadienides generates isostructural half-sandwich chromium(III)-μ -methylidynes [Cp Cr (μ -Cl) (μ -CH)] (Cp =C H , C Me , C H SiMe ). Side and decomposition products of the Cl/Cp exchange reactions were identified and structurally characterized for [Cr (μ -Cl) (μ -I) (μ -O)(thf) ] and [(η -C H SiMe )CrCl(μ -Cl) Li(thf) ].

Cerium-quinone redox couples put under scrutiny.

Homoleptic cerous complexes Ce[N(SiMe)], [Ce{OSi(OBu)}] and [Ce{OSiPr}] were employed as thermally robust, weakly nucleophilic precursors to assess their reactivity towards 1,4-quinones in non-aqueous solution. The strongly oxidizing quinones 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or tetrachloro-1,4-benzoquinone (ClBQ) readily form hydroquinolato-bridged ceric complexes of the composition [(CeL)(μ-OCR)]. Less oxidising quinones like 2,5-di--butyl-1,4-benzoquinone (BuBQ) tend to engage in redox equilibria with the ceric hydroquinolato-bridged form being stable only in the solid state.

Structure and Composition of the Eggshell of a Passerine Bird, (Linnaeus, 1758).

The mineral composition of eggshells is assumed to be a conserved phylogenetic feature. Avian eggshells are composed of calcite, whereas those of taxa within Chelonia are aragonitic. Yet, the eggshells of a passerine bird were reported to be made of aragonite.

Analysis of the Ordering Effects in Anthraquinone Thin Films and Its Potential Application for Sodium Ion Batteries.

The ordering effects in anthraquinone (AQ) stacking forced by thin-film application and its influence on dimer solubility and current collector adhesion are investigated. The structural characteristics of AQ and its chemical environment are found to have a substantial influence on its electrochemical performance. Computational investigation for different charged states of AQ on a carbon substrate obtained via basin hopping global minimization provides important insights into the physicochemical thin-film properties.

Perylenetetracarboxylic Diimide as Diffusion-Less Electrode Material for High-Rate Organic Na-Ion Batteries.

In this work 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) is investigated as electrode material for organic Na-ion batteries. Since PTCDI is a widely used industrial pigment, it may turn out to be a cost-effective, abundant, and environmentally benign cathode material for secondary Na-ion batteries. Among other carbonyl pigments, PTCDI is especially interesting due to its high Na-storage capacity in combination with remarkable high rate capabilities.

Substantially Improved Na-Ion Storage Capability by Nanostructured Organic-Inorganic Polyaniline-TiO Composite Electrodes.

Developing sodium (Na)-ion batteries is highly appealing because they offer the potential to be made from raw materials, which hold the promise to be less expensive, less toxic, and at the same time more abundant compared to state-of-the-art lithium (Li)-ion batteries. In this work, the Na-ion storage capability of nanostructured organic-inorganic polyaniline (PANI) titanium dioxide (TiO) composite electrodes is studied. Self-organized, carbon-coated, and oxygen-deficient anatase TiO -C nanotubes (NTs) are fabricated by a facile one-step anodic oxidation process followed by annealing at high temperatures in an argon-acetylene mixture.

Emergence of a New [NNN] Pincer Ligand via Si-H Bond Activation and β-Hydride Abstraction at Tetravalent Cerium.

The cerium(IV) pyrazolate complexes [Ce(Me pz) ] and [Ce(Me pz) (thf)] initiate β-hydride abstraction of the bis(dimethylsilyl)amido moiety, to afford a heteroleptic cerium(IV) species containing a dimethylpyrazolyl-substituted silylamido ligand, namely [Ce(Me pz) (bpsa)] (bpsa=bis((3,5-dimethylpyrazol-1-yl)dimethylsilyl)amido; Me pz =3,5-dimethylpyrazolato), along with some cerium(III) species. Remarkably, the nucleophilic attack of the pyrazolyl at the silicon atom and concomitant Si-H-bond cleavage is restricted to the tetravalent cerium oxidation state and appears to proceed via the formation of a transient cerium(IV) hydride, which engages in immediate redox chemistry. When [Ce(Me pz) ] is treated with [Li{N(SiMe ) }], that is, in the absence of the SiH functionality, any redox chemistry did not occur.

Effective and Reversible Carbon Dioxide Insertion into Cerium Pyrazolates.

The homoleptic pyrazolate complexes [Ce (Me pz) ] and [Ce (Me pz) ] quantitatively insert CO to give [Ce (Me pz⋅CO ) ] and [Ce (Me pz⋅CO ) ], respectively (Me pz=3,5-dimethylpyrazolato). This process is reversible for both complexes, as observed by in situ IR and NMR spectroscopy in solution and by TGA in the solid state. By adjusting the molar ratio, one molecule of CO per [Ce (Me pz) ] complex could be inserted to give trimetallic [Ce (Me pz) (Me pz⋅CO ) (thf)].

C-H-Bond Activation and Isoprene Polymerization Studies Applying Pentamethylcyclopentadienyl-Supported Rare-Earth-Metal Bis(Tetramethylaluminate) and Dimethyl Complexes.

As previously shown for lutetium and yttrium, 1,2,3,4,5-pentamethylcyclopentadienyl (CMe = Cp*)-bearing rare-earth metal dimethyl half-sandwich complexes [Cp*LnMe] are now also accessible for holmium, dysprosium, and terbium via tetramethylaluminato cleavage of [Cp*Ln(AlMe)] with diethyl ether (Ho, Dy) and tert-butyl methyl ether (TBME) (Tb). C-H-bond activation and ligand redistribution reactions are observed in case of terbium and are dominant for the next larger-sized gadolinium, as evidenced by the formation of mixed methyl/methylidene clusters [(Cp*Ln)(CH)(Me)] and metallocene dimers [Cp*Ln(AlMe)] (Ln = Tb, Gd). Applying TBME as a "cleaving" reagent can result in both TBME deprotonation and ether cleavage, as shown for the formation of the 24-membered macrocycle [(Cp*Gd)(Me)(CHOBu)(AlMe)] or monolanthanum complex [Cp*La(AlMe){MeAl(CH)OBu}] and monoyttrium complex [Cp*Y(AlMe)(MeAlOBu)], respectively.

Oligoanalgesia in Patients With an Initial Glasgow Coma Scale Score ≥8 in a Physician-Staffed Helicopter Emergency Medical Service: A Multicentric Secondary Data Analysis of >100,000 Out-of-Hospital Emergency Missions.

Background: Oligoanalgesia, as well as adverse events related to the initiated pain therapy, is prevalent in out-of-hospital emergency medicine, even when a physician is present. We sought to identify factors involved in insufficient pain therapy of patients presenting with an initial Glasgow Coma Scale (GCS) score of ≥8 in the out-of-hospital phase, when therapy is provided by a physician-staffed helicopter emergency medical service (p-HEMS).

Methods: This was a multicenter, secondary data analysis of conscious patients treated in primary p-HEMS missions between January 1, 2005, and December 31, 2017.

Trapping CS and S between Two Ytterbium Formamidinates.

Treatment of [Yb(DippForm)(thf) ] ( n = 2 (1aYb), n = 1 (1bYb); DippForm = N, N'-bis(2,6-diisopropylphenyl)formamidinate), with either excess CS or S gives [Yb(DippForm)(CS)] (3) and [Yb(DippForm)(S)/(S)] (4) respectively. 3 is a new addition to an exclusive class of compounds containing the CS dianion, and 4 is the first crystallographically characterized example of a rare-earth trisulfide complex.

Unveiling the Takai Olefination Reagent via Tris( tert-butoxy)siloxy Variants.

The elusive Takai olefination reagent, namely, the iodo-methylidene Cr(III) complex [CrCl(CHI)(thf)], has been isolated by careful handling of the reaction between CrCl and CHI in THF at -35 °C. Alternatively, treatment of [Cr(OSi(O tBu))] with CHI gave the mixed-valent dihalido-methanide complex [CrI(OSi(O tBu))(CHI)], featuring a Cr(III)-CHI moiety. In the presence of TMEDA nucleophilic attack at CHI occurred generating the zwitterionic species [Cr(OSi(O tBu))(tmeda-CHI)][I].