Surface Facets Research Articles

Surgical Anatomy of Vertebral Artery in Relation to Atlantoaxial Instrumentation: A Cadaveric Study.

With the advent of pedicle screws and advanced instrumentation techniques, internal fixation and stabilization of upper cervical vertebrae are possible in fractures of an axis. However, the proximity of vertebral arteries (VAs) poses a unique challenge to surgeons during these procedures and can result in profound physical impairment to patients. Cadaveric studies contributing to fine anatomical details necessitate conducting such studies. After receiving due ethical permission, this descriptive cross-sectional study was carried out on 10 cadavers in the department of Anatomy, All India Institute of Medical Science (AIIMS) Rishikesh. Twenty VAs were dissected along their course, and measurements of parameters related to the axis and atlas vertebra were noted. The length of the pre-osseous segment related to the axis (VAX-1) on the right and left sides were from 3.8 to 14.5 mm (7.48±3.88 mm)and 4.46 to 10.5mm (6.94±2.01mm) respectively. The length of the osseous segment related to the axis (VAX-2) on the right side and left sides were from 6.82 to 31 mm (17.9±7.84mm) and 7.35 to 20 mm (15.6±4.53). The osseous segment of the VA related to the axis (VAX-2) shows genu (bend), which extends to a variable distance towards the midline. The mean distance of VA genu from the midline of the axis vertebral body on the right and left sides was 15.6mm and 17.5 mm, respectively. The percentage of superior articular facet (SAF) surface area of the axis occupied by the VA was 25-50% in nine and 50-75% in 11 cadavers, reflecting incomplete occupancy. The study suggests that for instrumentation of the axis vertebra in the midline, the minimum distance between the genu of both sides of VA segments, related to an osseous segment of the axis (VAX-2) and medial extent of the VA groove of the atlas, should be considered as a safe zone to minimize inadvertent VA injury. During atlantoaxial fixation through a posterior approach in interarticular, pars, and pedicle screws, the surgical anatomy of the VA in relation to the osseous segment of the VA within the transverse process of the axis should be kept in mind to avoid inadvertent VA injury.

First-Principles Examination of Multiple Criteria of Organic Solvent Oxidative Stability in Batteries

Oxidative instability of the liquid electrolyte at or near battery cathode oxide surfaces has significant detrimental effects on batteries. Organic solvent molecules are often the fuel and precursors of such degradation processes, releasing electrons and protons that react with cathode oxides and electrolyte anions. These reactions contribute to cathode–electrolyte interphase (CEI) film formation, transition-metal ion dissolution, and phase transformation of the surface regions of the cathode. Here we apply density functional theory calculations to examine four criteria of oxidative stability (oxidation potential, hydrogen removal energies, and initial reactivity on two types of oxide facets) using four different solvent/additive molecules (ethylene carbonate, fluoroethylene carbonate, 1,3-dioxolane, and dimethyl ether). The ranking of molecular stability differs with each criterion. Surprisingly, the all-oxygen-terminated basal planes of layered oxides exhibit lower reaction barriers than spinel surface facets with exposed transition-metal cations, especially for ether solvents; the calculations also suggest basal planes contribute to the dissolution of transition-metal ions. The structure–degradation relation complexity underscores the challenge of understanding the function of the CEI but also offers a guide to future degradation-mitigation strategies including facet engineering. Our predictions and models help establish a framework for future studies relevant to high-voltage conditions.

The association between unilateral high-riding vertebral artery and atlantoaxial joint morphology: a multi-slice spiral computed tomography study of 396 patients and a finite element analysis

Background ContextA high-riding vertebral artery (HRVA) can deviate too medially, too posteriorly, or too superiorly to allow the safe insertion of screws. However, it is unknown whether the presence of a HRVA is associated with morphological changes of the atlantoaxial joint. PurposeTo investigate the association between HRVA and atlantoaxial joint morphology in patients with and without HRVA. Study DesignA retrospective case–control study and finite element (FE) analysis. Patient SampleA total of 396 patients with cervical spondylosis underwent multi-slice spiral computed tomography (MSCT) of cervical spine at our institutions from 2020 to 2022. Outcome MeasuresA series of atlantoaxial joint morphological parameters, including C2 lateral mass settlement (C2 LMS), C1–2 sagittal joint inclination (C1–2 SI), C1–2 coronal joint inclination (C1–2 CI), atlanto-dental interval (ADI), lateral atlanto-dental interval (LADI), and C1–2 relative rotation angle (C1–2 RRA) were measured, and lateral atlantoaxial joints osteoarthritis (LAJs-OA) was recorded. The stress distribution on the C2 facet surface under different torques of flexion-extension, lateral bending, and axial rotation was analyzed by FE models. A 2-Nm moment was applied to all models to determine the range of motion (ROM). MethodsA total of 132 consecutive cervical spondylosis patients with unilateral HRVA were enrolled in the HRVA group, and 264 patients without HRVA matched for age and sex were enrolled in the normal (NL) group. Atlantoaxial joint morphological parameters were compared between two sides of C2 lateral mass within HRVA or NL group, and between HRVA and NL groups. A 48-year-old woman with cervical spondylosis without HRVA was selected for cervical MSCT. A three-dimensional (3D) FE intact model of the normal upper cervical spine (C0-C2) was created. We established the HRVA model by simulating atlantoaxial morphological changes of unilateral HRVA with FE method. ResultsThe C2 LMS was significantly smaller on the HRVA side than that on the non-HRVA side in the HRVA group, but C1–2 SI, C1–2 CI, and LADI on HRVA side were significantly larger than those on non-HRVA side. There was no significant difference between left and right sides in the NL group. The difference in C2 LMS (d-C2 LMS) between HRVA side and non-HRVA side in the HRVA group was larger than that in the NL group (P < 0.05). Meanwhile, the differences in C1–2 SI (d-C1/2 SI), C1–2 CI (d-C1/2 CI), and LADI (d-LADI) in the HRVA group were significantly larger than those in the NL group. The C1–2 RRA in the HRVA group was significantly larger than that in the NL group. Pearson correlations showed that d-C1/2 SI, d-C1/2 CI, and d-LADI were positively associated with d-C2 LMS (r=0.428, 0.649, 0.498, respectively, p<.05 for all). The incidence of LAJs-OA in the HRVA group (27.3%) was significantly larger than that in the NL group (11.7%). Compared with the normal model, the ROM of C1-2 segment declined in all postures of the HRVA FE model. We found a larger distribution of stress on the C2 lateral mass surface of the HRVA side under different moment conditions. ConclusionsWe suggest that HRVA affects the integrity of the C2 lateral mass. This change in patients with unilateral HRVA is associated with the nonuniform settlement of the lateral mass and an increase in the lateral mass inclination, which may further affect the degeneration of the atlantoaxial joint because of the stress concentration on the C2 lateral mass surface.

Thermally induced surface faceting on heteroepitaxial layers

Heteroepitaxial semiconductors such as Ge-on-Si are widely used in current opto-electronic and electronic applications, and one of the most important challenges for epitaxial Ge-on-Si is threading dislocations (TDs) in Ge layers caused by lattice mismatch between Ge and Si. Here, apart from traditional wet chemical etching, we report a convenient approach to evaluate the threading dislocation densities in heteroepitaxial layers through vacuum thermal annealing. More importantly, the controversial origin of thermal annealing induced pits on a Ge surface was addressed in this work. By combining both experiments and density functional theory (DFT) calculations, we find that the {111} facets defined thermal pits on Ge (001) surfaces are mainly caused by threading dislocation activation. Ge adatoms at the TD segments sublimate preferentially than the ones on dislocation-free Ge (001) surface regions, and its further evolution is determined by surface energies of {111} facets, leading to a construction of inverted pyramid-shaped thermal pits.

G-C3N4 Nanosheet Supported CuO Nanocomposites for the Electrochemical Carbon Dioxide Reduction Reaction.

We have prepared CuO-derived electrocatalysts on a graphitic carbon nitride (g-C3N4) nanosheet support for the electrochemical carbon dioxide reduction reaction (CO2RR). Highly monodisperse CuO nanocrystals made by a modified colloidal synthesis method serve as the precatalysts. We use a two-stage thermal treatment to address the active site blockage issues caused by the residual C18 capping agents. The results show that the thermal treatment effectively removed the capping agents and increased the electrochemical surface area. During the process, the residual oleylamine molecules incompletely reduced CuO to a Cu2O/Cu mixed phase in the first stage of thermal treatment, and the following treatment in forming gas at 200 °C completed the reduction to metallic Cu. The CuO-derived electrocatalysts show different selectivities over CH4 and C2H4, and this might be due to the synergistic effects of Cu-g-C3N4 catalyst-support interaction, varied particle sizes, dominant surface facets, and catalyst ensemble. The two-stage thermal treatment enables sufficient capping agent removal, catalyst phase control, and CO2RR product selection, and with precise controls of the experimental parameters, we believe that this will help to design and fabricate g-C3N4-supported catalyst systems with narrower product distribution.

Post-Traumatic Atlanto-Axial Instability: A Combined Clinical and Radiological Approach for the Diagnosis of Pathological Rotational Movement in the Upper Cervical Spine

Post-traumatic rotational instability at the atlanto-axial (C1-2) joint is difficult to assess, much less quantify, due to the orientation and motion plane of the joint. Prior investigations have demonstrated that a dynamic axial CT scan, during which the patient maximally rotates the head right and left, can be used to evaluate and quantify the amount of residual overlap between the inferior articulating facet of C1 and the superior facet of C2, as an index of ligamentous laxity at the joint. We have previously demonstrated that a novel orthopedic test of rotational instability, the atlas-axis rotational test (A-ART), may have utility in identifying patients with imaging evidence of upper cervical ligament injury. In the present investigation, we assessed the correlation between a positive A-ART and a CT scan assessment of the relative quantity of residual C1-2 overlap, as a percent of the superior articulating facet surface area of C2. A retrospective review was conducted of the records of consecutive patients presenting to a physical therapy and rehabilitation clinic, over a 5-year period (2015-20) for chronic head and neck pain after whiplash trauma. The primary inclusion criteria were that the patient had undergone both a clinical evaluation with A-ART and a dynamic axial CT to evaluate for C1-2 residual facet overlap at maximum rotation. The records for a total of 57 patients (44 female/13 male) were identified who fit the selection criteria, and among these, there were 43 with a positive A-ART (i.e., "cases") and 14 with a negative A-ART (i.e., "controls). The analysis demonstrated that a positive A-ART was highly predictive of decreased residual C1-2 facet overlap: the average overlap area among the cases was approximately one-third that of the control group (on the left, 10.7% versus 29.1%, and 13.6% versus 31.0% on the right). These results suggest that a positive A-ART is a reliable indicator of underlying rotational instability at C1-2 in patients with chronic head and neck symptoms following whiplash trauma.

Electroreduction of CO2 on Au(310)@Cu High-index Facets.

The chemical selectivity and faradaic efficiency of high-index Cu facets for the CO2 reduction reaction (CO2 RR) is investigated. More specifically, shape-controlled nanoparticles enclosed by Cu {hk0} facets are fabricated using Cu multilayer deposition at three distinct layer thicknesses on the surface facets of Au truncated ditetragonal nanoprisms (Au DTPs). Au DTPs are shapes enclosed by 12 high-index {310} facets. Facet angle analysis confirms DTP geometry. Elemental mapping analysis shows Cu surface layers are uniformly distributed on the Au {310} facets of the DTPs. The 7 nm Au@Cu DTPs high-index {hk0} facets exhibit a CH4 : CO product ratio of almost 10 : 1 compared to a 1 : 1 ratio for the reference 7 nm Au@Cu nanoparticles (NPs). Operando Fourier transform infrared spectroscopy spectra disclose reactive adsorbed *CO as the main intermediate, whereas CO stripping experiments reveal the high-index facets enhance the *CO formation followed by rapid desorption or hydrogenation.

Electroreduction of CO2 on Au(310)@Cu High‐index Facets

AbstractThe chemical selectivity and faradaic efficiency of high‐index Cu facets for the CO2 reduction reaction (CO2RR) is investigated. More specifically, shape‐controlled nanoparticles enclosed by Cu {hk0} facets are fabricated using Cu multilayer deposition at three distinct layer thicknesses on the surface facets of Au truncated ditetragonal nanoprisms (Au DTPs). Au DTPs are shapes enclosed by 12 high‐index {310} facets. Facet angle analysis confirms DTP geometry. Elemental mapping analysis shows Cu surface layers are uniformly distributed on the Au {310} facets of the DTPs. The 7 nm Au@Cu DTPs high‐index {hk0} facets exhibit a CH4 : CO product ratio of almost 10 : 1 compared to a 1 : 1 ratio for the reference 7 nm Au@Cu nanoparticles (NPs). Operando Fourier transform infrared spectroscopy spectra disclose reactive adsorbed *CO as the main intermediate, whereas CO stripping experiments reveal the high‐index facets enhance the *CO formation followed by rapid desorption or hydrogenation.

Strain-Driven Faceting of Graphene-Catalyst Interfaces.

The interfacial interaction of 2D materials with the substrate leads to striking surface faceting affecting its electronic properties. Here, we quantitatively study the orientation-dependent facet topographies observed on the catalyst under graphene using electron backscatter diffraction and atomic force microscopy. The original flat catalyst surface transforms into two facets: a low-energy low-index surface, e.g. (111), and a vicinal (high-index) surface. The critical role of graphene strain, besides anisotropic interfacial energy, in forming the observed topographies is revealed by molecular simulations. These insights are applicable to other 2D/3D heterostructures.

Hierarchical Pt-In Nanowires for Efficient Methanol Oxidation Electrocatalysis.

Direct methanol fuel cells (DMFC) have attracted increasing research interest recently; however, their output performance is severely hindered by the sluggish kinetics of the methanol oxidation reaction (MOR) at the anode. Herein, unique hierarchical Pt-In NWs with uneven surface and abundant high-index facets are developed as efficient MOR electrocatalysts in acidic electrolytes. The developed hierarchical Pt89In11 NWs exhibit high MOR mass activity and specific activity of 1.42 A mgPt-1 and 6.2 mA cm-2, which are 5.2 and 14.4 times those of Pt/C, respectively, outperforming most of the reported MORs. In chronoamperometry tests, the hierarchical Pt89In11 NWs demonstrate a longer half-life time than Pt/C, suggesting the better CO tolerance of Pt89In11 NWs. After stability, the MOR activity can be recovered by cycling. XPS, CV measurement and CO stripping voltammetry measurements demonstrate that the outstanding catalytic activity may be attributed to the facile removal of CO due to the presence of In site-adsorbing hydroxyl species.

Ni Ingress and Egress in SrTiO3 Single Crystals of Different Facets

Metal-ion surface interactions and/or doping in host perovskite-oxides are techniques that are widely employed for electronic structure tuning purposes and in developing novel heterogeneous catalysts; however, an in-depth understanding of the different elementary steps and factors involved in these processes is lacking. Herein, we use Atomic Force Microscopy (AFM), Scanning Transmission Electron Microscopy (STEM), and ab initio thermodynamics through density functional theory (DFT) to specifically investigate Ni surface adsorption, ingress, migration, segregation, and egress processes across different SrTiO3 (STO) single-crystal facets and terminations, specifically the (001), (110), and the (111). Under oxidizing and reducing conditions at different temperatures, Ni egress is observed on (110) STO samples, but not the (001). DFT results demonstrate Ni to have a higher thermodynamic egress propensity, specifically through an oxygen-terminated (110) facet in comparison to other (001) terminations, whereas for the (111)-Ti terminated facet, Ni is likely to remain in the bulk post ingress. We suggest that the observed uniqueness of the (110) surface facet toward Ni egress is possibly a consequence of a surface phase transition. These results can help guide design interests with regard to Ni surface stabilization, ingress/egress suppression, or facilitation in STO by elucidating the nuances involved across different facets.

Analysis of the alveolar shape in 3-D.

Mechanical forces affect the alveolar shape, depending on location and tissue composition, and vary during the respiratory cycle. This study performs alveolar morphomics in different lobes of human lungs using models generated from three-dimensional (3-D) micro-computed tomography (microCT) images. Cylindrical tissue samples (1.6 cm × 2 cm) were extracted from two nontransplantable donor lungs (one ex-smoker and one smoker, 3 samples per subject) that were air-inflated and frozen solid in liquid nitrogen vapor. Samples were scanned with microCT (11 µm/voxel). Within representative cubic regions of interest (5.5 mm edge length), alveoli were segmented to produce corresponding 3-D models from which quantitative data were obtained. The surface of segmented alveoli (n_alv_total = 23,587) was divided into individual planar surfaces (facets) and angles between facet normals were calculated. Moreover, the number of neighboring alveoli was estimated for every alveolus. In this study, we examined intraindividual differences in alveolar morphology, which were reproducible in the lungs of two subjects. The main aspects are higher mean alveolar volumes (v_alv: 6.64 × 106 and 6.63 × 106 µm3 vs. 5.78 × 106 and 6.29 × 106 µm3) and surface sizes (s_alv: 0.19 and 0.18 mm2 vs. 0.17 mm2 in both lower lobes) in both upper lung lobes compared with the lower lobes. An increasing number of facets (f_alv) from top to bottom (12 and 14 in the upper lobes; 14 and 15 in the lower lobes), as well as a decreasing number of alveolar neighbors (nei_alv: 9 and 8 in the upper lobes; 8 and 7 in the lower lobes) from the upper lobes to the lower lobes were observed. We could observe an increasing ratio of alveolar entrance size to the surface size of the alveoli from top to bottom (S_ratio_alv: 0.71 and 0.64 in the upper lobes, 0.73 and 0.70 in the lower lobes). The angles between facet normals (ang_alv) were larger in the upper lobes (67.72° and 62.44°) of both lungs than in the lower lobes (66.19° and 61.30°). By using this new approach of analyzing alveolar 3-D data, which enables the estimation of facet, neighbor, and shape characteristics, we aimed to establish the baseline measures for in-depth studies of mechanical conditions and morphology.

Wave-layered dendrite-free lithium deposition with unprecedented long-term cyclability

Lithium dendrite growth on the anode during cycling leads to poor stability and severe safety issue, hampering long-term cycle for high-energy batteries. Herein, we firstly found that dendrite-free Li can be deposited layer-by-layer on the surface of lithiophilic Li3N (001) or (111) facet, and then synthesized a composite electrode of Li3N involving a high fraction of (001) facet on porous carbon cloth (P-CC), wherein Li3N in-situ formed by immersing of P-CC in a solution of molten Li, offering outstanding electrochemical and battery performance. Unique waved-layered dendrite free Li deposition has been detected during the Li-plating/stripping process. This P-CC/Li3N/Li anode exhibits a cycle lifespan as long as 2000 h with low overpotential of ∼20 mV at 1 mA cm−2 in a symmetrical cell, which overwhelms all similar systems reported so far. Attractively, long-term operations of 35, 200, and 400 h at 10 mA cm−2 can be achieved at temperatures of −10, 25, and 50 °C, respectively. Both experimental and density functional theory calculations confirm that the P-CC/Li3N serves as an appropriate host for Li infusion through an efficient ion conductive network, inducing the nucleation and growth of metallic lithium.

Facet Connectivity-Based Estimation Algorithm for Manufacturability of Supportless Parts Fabricated via LPBF.

Recent advances in additive manufacturing have provided more freedom in the design of metal parts; hence, the prototyping of fluid machines featuring extremely complex geometries has been investigated extensively. The fabrication of fluid machines via additive manufacturing requires significant attention to part stability; however, studies that predict regions with a high risk of collapse are few. Therefore, a novel algorithm that can detect collapse regions precisely is proposed herein. The algorithm reflects the support span over the faceted surface via propagation and invalidates overestimated collapse regions based on the overhang angle. A heat exchanger model with an extremely complex internal space is adopted to validate the algorithm. Three samples from the model are extracted and their prototypes are fabricated via laser powder bed fusion. The results yielded by the fabricated samples and algorithm with respect to the sample domain are compared. Regions of visible collapse identified on the surface of the fabricated samples are predicted precisely by the algorithm. Thus, the supporting span reflected by the algorithm provides an extremely precise prediction of collapse.

Paper-Based Hydrogen Sensors Using Ultrathin Palladium Nanowires

Hydrogen (H2), as a chemical energy carrier, is a cleaner alternative to conventional fossil fuels with zero carbon emission and high energy density. The development of fast, low-cost, and sensitive H2 detection systems is important for the widespread adoption of H2 technologies. Paper is an environment-friendly, porous, and flexible material with great potential for use in sustainable electronics. Here, we report a paper-based sensor for room-temperature H2 detection using ultrathin palladium nanowires (PdNWs). To elucidate the sensing mechanism, we compare the performance of polycrystalline and quasi-single-crystalline PdNWs. The polycrystalline PdNWs showed a response of 4.3% to 1 vol % H2 with response and recovery times of 4.9 and 10.6 s, while quasi-single-crystalline PdNWs showed a response of 8% to 1 vol % H2 with response and recovery times of 9.3 and 13.0 s, respectively. The polycrystalline PdNWs show excellent selectivity, stability, and sensitivity, with a limit of detection of 10 ppm H2 in air. The fast response of ultrathin polycrystalline PdNW paper-based sensors arises from the synergistic effects of their ultrasmall diameter, high-index surface facets, strain-coupled grain boundaries, and porous paper substrate. This paper-based sensor is one of the fastest chemiresistive H2 sensors reported and is potentially orders of magnitude less expensive than current state-of-the-art H2-sensing solutions. This brings low-cost, room-temperature chemiresistive H2 sensing closer to the performance of ultrafast optical sensors and high-temperature metal oxide-based sensors.

Polarization Controlled Assembly of Ultrathin Thiorphan Nanostructures on ZnO Surface Facets

Despite the importance of thiorphan as a small molecule with vital biological roles, its interactions with zinc oxide (ZnO) nanomaterials that are prospective in drug delivery and theranostic applications have not yet been sufficiently explored. Here the impact of surface polarity of different ZnO facets on thiorphan adsorption is studied both experimentally by atomic force microscopy (AFM) and angle resolved X-ray photoelectron spectroscopy (XPS) and theoretically by force field molecular dynamics (FFMD) and density functional tight binding simulations (DFTB). Polar ZnO surfaces cause the formation of thiorphan nanodots, where the size of the nanodots depends on the direction of dipoles: small (4 nm) nanodots are formed on Zn-face ZnO, while large (25 nm) nanodots are formed on O-face ZnO. Nonpolar ZnO surfaces cause self-assembly into layered nanoislands with characteristic 4 nm layer thickness, which subsequently merge into rigid nanolayers. The self-assembly is shown to be controlled solely by the effect of surface dipole electric field orientation and magnitude, whereas effects of surface chemistry or solution are negligible. The results thus also show a way for controlling the assembly of thiorphan and other molecular nanomaterials for diverse applications.

In situ annealing studies on the microstructural evolution of a macro defect free electroformed nanocrystalline Ni-Co sheet metal and its relation to tensile properties

The effect of annealing at temperatures between 200 – 400 °C on the microstructural evolution and tensile properties of a recently developed macro defect free electroformed nanocrystalline Ni-32at%Co free-standing sheet metal was investigated. The tensile strength of the materials exhibited an extrinsic Hall-Petch (HP) to inverse Hall-Petch (IHP) transition due to grain growth. In situ transmission electron microscopy (TEM) annealing revealed for the first time that at lower annealing temperatures, in addition to reordering of atoms at grain boundaries, grain rotation and grain recovery were also found to be mechanisms for grain boundary relaxation (GBR). Combined, these mechanisms contribute to the increase in ultimate tensile strength (UTS) observed in the IHP regime of the Ni-32at%Co alloy. TEM energy dispersive X-ray spectroscopy (EDX) and in situ synchrotron X-ray diffraction (XRD) annealing analyses showed that the drop in UTS and ductility in the HP regime after annealing at higher temperatures was associated with the onset of abnormal grain growth and sulfur impurity segregation to random high angle boundaries. Atom probe tomography (APT) further showed that there is no sulfur impurity segregation in the electroformed material before annealing. Increasing in annealing temperature led therefore to a transition from ductile to brittle fracture manifested as a change in dimple to mixed and eventually to faceted brittle fracture surfaces at 400 °C.

Platinum-Cobalt Nanowires for Efficient Alcohol Oxidation Electrocatalysis.

The compositions and surface facets of platinum (Pt)-based electrocatalysts are of great significance for the development of direct alcohol fuel cells (DAFCs). We reported an approach for preparing ultrathin PtnCo100-n nanowire (NW) catalysts with high activity. The PtnCo100-n NW alloy catalysts synthesized by single-phase surfactant-free synthesis have adjustable compositions and (111) plane and strain lattices. X-ray diffraction (XRD) results indicate that the alloy composition can adjust the lattice shrinkage or expansion of PtnCo100-n NWs. X-ray photoelectron spectroscopy (XPS) results show that the electron structure of Pt is changed by the alloying effect caused by electron modulation in the d band, and the chemical adsorption strength of Pt is decreased, thus the catalytic activity of Pt is increased. The experimental results show that the activity of PtnCo100-n for the oxidation of methanol and ethanol is related to the exposed crystal surface, strain lattice and composition of catalysts. The PtnCo100-n NWs exhibit stronger electrocatalytic performance for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The dominant (111) plane Pt53Co47 exhibits the highest electrocatalytic activity in MOR, which is supported by the results of XPS. This discovery provides a new pathway to design high activity, stability nanocatalysts to enhance direct alcohol fuel cells.

A new species of Comahuesuchus Bonaparte, 1991 (Crocodyliformes: Notosuchia) from the Upper Cretaceous of Neuquén, Lake Barreales, Patagonia, Argentina.

Notosuchian crocodyliforms were major components of the South American Cretaceous biota and, for over 125 years, paleontological fieldwork in this continent recovered several well-preserved fossils of these animals. They are largely recognized for terrestrial life and specialized feeding habits, frequently presenting bizarre taxa such as Comahuesuchus. A new species, Comahuesuchus bonapartei n. sp. (MUCPv 597; cast MN), is described from geological strata of Sierra Barrosa Formation (Upper Turonian) and Portezuelo Formation (Lower Coniacian) of Lake Barreales, Patagonia, Argentina. The new fossil comprises a right dentary bone that shares important and unique anatomical features with specimens of Comahuesuchus brachybuccalis, such as the presence of a well-marked shelf on the lateral surface of the bone; a flat, low, and wide mandibular symphysis; an enlarged, labiolingually compressed caniniform tooth at caudal position in the dentary; the presence of serrated mesial and distal carinae in the caniniform with a faceted labial surface, and the absence or extremely reduction in number of the postcaniniform dentition. C. bonapartei differs from C. brachybuccalis in having individual dentary alveoli, rather a dentition set in groove. Phylogenetic analyses support a sister-relationship between both species, which are well nested within notosuchians.

Pt cocatalyst morphology on semiconductor nanorod photocatalysts enhances charge trapping and water reduction.

In photocatalysis, metal-semiconductor hybrid structures have been proposed for ideal photocatalytic systems. In this study, we investigate the effect of morphology and surface nature of Pt cocatalysts on photocatalytic hydrogen evolution activity in Pt-tipped CdSe nanorods. Three distinct morphologies of Pt cocatalysts were synthesized and employed as visible light photocatalysts. The rough tips exhibit the highest activity, followed by the round and cubic tips. Kinetic investigations using transient absorption spectroscopy reveal that the cubic tips exhibit lower charge-separated states feasible for reacting with water and water reduction rates due to their defectless surface facets. In contrast, the rough tips show a similar charge-separation value but a two-fold higher surface reaction rate than the round tips, resulting in a significant enhancement of hydrogen evolution. These findings highlight the importance of rational design on metal cocatalysts in addition to the main semiconductor bodies for maximizing photocatalytic activities.