Challenges and Future Perspectives for Additively Manufactured Polylactic Acid Using Fused Filament Fabrication in Dentistry.

Additive manufacturing (AM), which is also called rapid prototyping/3D printing/layered manufacturing, can be considered as a rapid conversion between digital and physical models. One of the most used materials in AM is polylactic acid (PLA), which has advantageous material properties such as biocompatibility, biodegradability, and nontoxicity. For many medical applications, it is considered as a leading biomaterial.

Data on Cu- and Ni-Si-Mn-rich solute clustering in a neutron irradiated austenitic stainless steel.

The data presented in this article is supplementary to the research article "Phase instabilities in austenitic steels during particle bombardment at high and low dose rates" (Levine et al.) [5]. Needle-shaped samples were prepared with focused ion beam milling from a 304L stainless steel that was irradiated with fast neutrons (E 0.

The MAPS: Toward a Novel Mobility Assistance System for Visually Impaired People.

This paper introduces the design of a novel indoor and outdoor mobility assistance system for visually impaired people. This system is named the MAPS (Mobility Assistance Path Planning and orientation in Space), and it is based on the theoretical frameworks of mobility and spatial cognition. Its originality comes from the assistance of two main functions of navigation: locomotion and wayfinding.

A Logarithmic Formulation for Anisotropic Behavior Characterization of Bovine Cortical Bone Tissue in Long Bones Undergoing Uniaxial Compression at Different Speeds.

The mechanical properties of bone tissues change significantly within the bone body, since it is considered as a heterogeneous material. The characterization of bone mechanical properties is necessary for many studies, such as in prosthesis design. An experimental uniaxial compression study is carried out in this work on bovine cortical bone tissue in long bones (femur and tibia) at several speeds to characterize its anisotropic behavior.

Design and Production of a New FeCoNiCrAlCu High-Entropy Alloy: Influence of Powder Production Method on Sintering.

The structure of FeCoNiCrAl1.8Cu0.5 high-entropy alloys (HEA) obtained by two different routes has been studied.

D-Sorbitol Physical Properties Effects on Filaments Used by 3D Printing Process for Personalized Medicine.

Fused filament fabrication (FFF) is a process used to manufacture oral forms adapted to the needs of patients. Polyethylene oxide (PEO) filaments were produced by hot melt extrusion (HME) to obtain a filament suitable for the production of amiodarone hydrochloride oral forms by FFF 3D printing. In order to produce personalized oral forms adapted to the patient characteristics, filaments used by FFF must be controlled in terms of mass homogeneity along filament.

Production of Reproducible Filament Batches for the Fabrication of 3D Printed Oral Forms.

Patients need medications at a dosage suited to their physiological characteristics. Three-dimensional printing (3DP) technology by fused-filament fabrication (FFF) is a solution for manufacturing medication on demand. The aim of this work was to identify important parameters for the production of reproducible filament batches used by 3DP for oral formulations.

Efficient System Reliability-Based Design Optimization Study for Replaced Hip Prosthesis Using New Optimized Anisotropic Bone Formulations.

An efficient reliability algorithm is developed to transfer the system reliability problem to a single-component reliability problem, considering the uncertainty of loading cases and the material properties. The main difficulty is that femoral bone densities change after hip arthroplasty and, thus, the mechanical properties of the distinctive bone tissues and, therefore, the corresponding elasticity modulus and yield stress values change. Therefore, taking these changes into account during the hip prosthesis design process is strongly needed.

Design of core-shell titania-heteropolyacid-metal nanocomposites for photocatalytic reduction of CO to CO at ambient temperature.

The photocatalytic conversion of CO not only reduces the greenhouse effect, but also provides value-added solar fuels and chemicals. Herein, we report the design of new efficient core-shell nanocomposites for selective photocatalytic CO to CO conversion, which occurs at ambient temperature. A combination of characterization techniques (TEM, STEM-EDX, XPS, XRD, FTIR photoluminescence) indicates that the CO reduction occurs over zinc species highly dispersed on the heteropolyacid/titania core-shell nanocomposites.

Early warning sensors for monitoring mercury in water.

Poly-4-vinylpyridine grafted poly(vinylidene difluoride) (P4VP-g-PVDF) nanoporous polymer electrodes were found to be sensitive for Hg(II) analysis. The fabrication and characterization of functionalized nanoporous membrane-electrodes by FESEM and FTIR are presented. Functionalized nanopore charge state versus a large range of pH (1-10) was investigated by registering the streaming potential.

New Atom Probe Tomography Reconstruction Algorithm for Multilayered Samples: Beyond the Hemispherical Constraint.

Accuracy of atom probe tomography measurements is strongly degraded by the presence of phases that have different evaporation fields. In particular, when there are perpendicular interfaces to the tip axis in the specimen, layers thicknesses are systematically biased and the resolution is degraded near the interfaces. Based on an analytical model of field evaporated emitter end-form, a new algorithm dedicated to the 3D reconstruction of multilayered samples was developed.

Dissociation Dynamics of Molecular Ions in High dc Electric Field.

In an atom probe, molecular ions can be field evaporated from the analyzed material and, then, can dissociate under the very intense electric field close to the field emitter. In this work, field evaporation of ZnO reveals the emission of Zn2O2(2+) ions and their dissociation into ZnO(+) ions. It is shown that the repulsion between the produced ZnO(+) ions is large enough to have a measurable effect on both the ion trajectories and times of flight.

Transition-Metal Carbodiimides as Molecular Negative Electrode Materials for Lithium- and Sodium-Ion Batteries with Excellent Cycling Properties.

We report evidence for the electrochemical activity of transition-metal carbodiimides versus lithium and sodium. In particular, iron carbodiimide, FeNCN, can be efficiently used as negative electrode material for alkali-metal-ion batteries, similar to its oxide analogue FeO. Based on (57)Fe Mössbauer and infrared spectroscopy (IR) data, the electrochemical reaction mechanism can be explained by the reversible transformation of the Fe-NCN into Li/Na-NCN bonds during discharge and charge.

Size distribution and volume fraction of T(1) phase precipitates from TEM images: Direct measurements and related correction.

Transmission Electron Microscopy (TEM) can be used to measure the size distribution and volume fraction of fine scale precipitates in metallic systems. However, such measurements suffer from a number of artefacts that need to be accounted for, related to the finite thickness of the TEM foil and to the projected observation in two dimensions of the microstructure. We present a correction procedure to describe the 3D distribution of disc-like particles and apply this method to the plate-like T1 precipitates in an Al-Li-Cu alloy in two ageing conditions showing different particle morphologies.

An analytical model accounting for tip shape evolution during atom probe analysis of heterogeneous materials.

An analytical model describing the field evaporation dynamics of a tip made of a thin layer deposited on a substrate is presented in this paper. The difference in evaporation field between the materials is taken into account in this approach in which the tip shape is modeled at a mesoscopic scale. It was found that the non-existence of sharp edge on the surface is a sufficient condition to derive the morphological evolution during successive evaporation of the layers.

Comparative mutagenicity and genotoxicity of particles and aerosols emitted by the combustion of standard vs. rapeseed methyl ester supplemented bio-diesel fuels: impact of after treatment devices: oxidation catalyst and particulate filter.

Diesel exhausts are partly responsible for the deleterious effects on human health associated with urban pollution, including cardiovascular diseases, asthma, COPD, and possibly lung cancer. Particulate fraction has been incriminated and thus largely investigated for its genotoxic properties, based on exposure conditions that are, however, not relevant for human risk assessment. In this paper, original and more realistic protocols were used to investigate the hazards induced by exhausts emitted by the combustion of standard (DF0) vs.

Understanding Atom Probe Tomography of Oxide-Supported Metal Nanoparticles by Correlation with Atomic-Resolution Electron Microscopy and Field Evaporation Simulation.

Oxide-supported metal nanoparticles are widely used in heterogeneous catalysis. The increasingly detailed design of such catalysts necessitates three-dimensional characterization with high spatial resolution and elemental selectivity. Laser-assisted atom probe tomography (APT) is uniquely suited to the task but faces challenges with the evaporation of metal/insulator systems.

Correlation of microphotoluminescence spectroscopy, scanning transmission electron microscopy, and atom probe tomography on a single nano-object containing an InGaN/GaN multiquantum well system.

A single nanoscale object containing a set of InGaN/GaN nonpolar multiple-quantum wells has been analyzed by microphotoluminescence spectroscopy (μPL), high-resolution scanning transmission electron microscopy (HR-STEM) and atom probe tomography (APT). The correlated measurements constitute a rich and coherent set of data supporting the interpretation that the observed μPL narrow emission lines, polarized perpendicularly to the crystal c-axis and with energies in the interval 2.9-3.

Tandem mass spectrometry of low solubility polyamides.

The structural characterization of polyamides (PA) was achieved by tandem mass spectrometry (MS/MS) with a laser induced dissociation (LID) strategy. Because of interferences for precursor ions selection, two chemical modifications of the polymer end groups were proposed as derivatization strategies. The first approach, based on the addition of a trifluoroacetic acid (TFA) molecule, yields principally to complementary bn and yn product ions.

Coupling atom probe tomography and photoluminescence spectroscopy: exploratory results and perspectives.

The development of laser-assisted atom probes makes it possible, in principle, to exploit the femtosecond laser pulse not only for triggering ion evaporation from a nanometric field emission tip, but also for generating photons via the radiative recombination of electron-hole pairs in tips made of dielectric materials. In this article we demonstrate a first step towards a correlation of micro-photoluminescence (μ-PL) and laser-assisted tomographic atom probe (LA-TAP) analysis applied separately on the same objects, namely on ZnO microwires. In particular, we assess that the use of the focused ion beam (FIB) tip preparation method significantly degrades the radiative recombination yield of the analyzed microwires.

Scaffold hopping strategy toward original pyrazolines as selective CB₂ receptor ligands.

In line of a scaffold hopping strategy of pyrazole structures, especially known as potent CB(2) receptor antagonists, we exploited an original and convergent synthesis of a new class of C4-benzyl pyrazolines and derivatives from readily available hydrazones and enones (two or three steps). Making use of a mixture of resin supported reagents strategy an efficient domino process allowed the easy construction of various dihydropyrazoles in 63-83% yields. The obtained family of pyrazolines featured significant hCB(2)/hCB(1) selectivity in favor of hCB(2) receptors while more than 1000-3000 nM affinity was only measured for hCB(1) receptors.

Indium-promoted Reformatsky reaction: a straightforward access to β-amino and β-hydroxy α,α-difluoro carbonyl compounds.

A versatile and practical methodology to access β-amino and β-hydroxy α,α-difluoro carbonyl compounds using indium metal is described. This methodology has been successfully applied to a broad range of substrates including aldehydes, ketones, and imines, affording the corresponding and highly valuable gem-difluoro esters. The wide substrate scope highlights the chemoselectivity of the process.

Enantioselective synthesis of bio-relevant 3,5-diaryl pyrazolines.

The straightforward asymmetric construction of bio-relevant Δ(2)-pyrazolines having either N-(thio)amide or N-acetyl functional groups and flanked by aryl substituents such as phenol at C3 and C5 has been achieved through an enantioselective phase transfer organocatalytic addition of N-Boc hydrazine to chalcones followed by a transprotection sequence allowing N-Boc transformation into N-CXNHR (X = S, O) or N-Ac functional groups. This approach was applied to a straightforward elaboration of chiral monoamine oxidase inhibitor derivatives.

Vectorial complex ray model and application to two-dimensional scattering of plane wave by a spheroidal particle.

A vectorial complex ray model is introduced to describe the scattering of a smooth surface object of arbitrary shape. In this model, all waves are considered as vectorial complex rays of four parameters: amplitude, phase, direction of propagation, and polarization. The ray direction and the wave divergence/convergence after each interaction of the wave with a dioptric surface as well as the phase shifts of each ray are determined by the vector Snell law and the wavefront equation according to the curvatures of the surfaces.