Protein encapsulation in functionalized sol–gel silica: influence of organosilanes and main silica precursors

Journal of Materials Science - Over the last few years, bone repair has increasingly gained in importance. In recent years, considerable attention has been given to the administration of...     

Microscale Thermophoresis as a Tool to Study Protein Interactions and Their Implication in Human Diseases

The review highlights how protein–protein interactions (PPIs) have determining roles in most life processes and how interactions between protein partners are involved in various human diseases. The study of PPIs and binding interactions as well as their understanding, quantification and pharmacological regulation are crucial for therapeutic purposes. Diverse computational and analytical methods, combined with high-throughput screening (HTS), have been extensively used to characterize multiple types of PPIs, but these procedures are generally laborious, long and expensive. Rapid, robust and efficient alternative methods are proposed, including the use of Microscale Thermophoresis (MST), which has emerged as the technology of choice in drug discovery programs in recent years. This review summarizes selected case studies pertaining to the use of MST to detect therapeutically pertinent proteins and highlights the biological importance of binding interactions, implicated in various human diseases. The benefits and limitations of MST to study PPIs and to identify regulators are discussed.     

Theoretical and experimental study of the flow of a molten polymer in a micro-compounder

Micro-compounders are more and more used to characterize and optimize the formulations and the flow conditions of complex materials, with very low quantities, around a few grams. These machines are composed of a small-size conical twin-screw extruder, coupled with a recirculating channel, in which the material can be processed during a fixed time and a certain number of cycles, before being purged. However, the precise flow conditions inside these machines are not well known, what makes an optimal interpretation of the results difficult. Therefore, in this paper, a theoretical model based on continuum mechanics is proposed to calculate the flow in the recirculating mode. An experimental study on a well-chosen polymer is carried out to define the influences of the main processing parameters (screw speed, mass of material, barrel temperature) and to validate the model. Despite the simplicity of the theoretical approach, the calculated results are in satisfactory agreement with the experiments.     

Turbulent mixing and molecular transport in highly under-expanded hydrogen jets

Highly under-expanded hydrogen jets releasing in quiescent air atmosphere are studied using highly resolved numerical simulations accounting for complex multicomponent molecular transport phenomena. In a first step of the analysis, the main overall features of the hydrogen jet structure are described and compared to those of the classical under-expanded air jet at the same nozzle pressure ratio (NPR). Even if the global flow topology remains quite similar in both cases (i.e., hydrogen and air discharges), the modification of both mean density and mean velocity gradients leads to different relative energy levels for each velocity component. The corresponding change of fluid properties mainly leads to an enhanced mixing at the jet periphery. In comparison to the air case, the turbulence development within the internal part of the under-expanded hydrogen jet surrounding the subsonic core also yields a different structure. While a significantly higher peak of streamwise turbulent stress is observed downstream of the reflected shock, the vorticity dynamics is dampened by viscous diffusion and velocity divergence (i.e., volumetric expansion) contributions. Then, the performance of the simplified Hirschfelder and Curtiss approximation of the multicomponent molecular diffusion phenomena is evaluated with respect to the detailed multicomponent transport representation, as deduced from the EGLIB library. The detailed representation of molecular phenomena is shown to have a significant influence on the estimated local levels of hydrogen mass flux, leading to a non-negligible alteration of the global jet structure.     

Automatic Choice of the Threshold of a Grain Filter via Galton–Watson Trees: Application to Granite Cracks Detection

The goal of this paper is the presentation of a post-processing method allowing to remove impulse noise in binary images, while preserving thin structures. We use a grain filter. We propose a method to automatically determine the required threshold using Galton–Watson processes. We present numerical results and a complete analysis on a synthetic image. We end the numerical section considering a specific application to granite samples crack detection: Here we deal with X-tomography images that have been binarized via preprocessing techniques and we want to remove residual impulse noise while keeping cracks and micro-cracks structure.     

Use of 300,000 pseudo-experimental data over 1800 pure fluids to assess the performance of four cubic equations of state: SRK,PR, tc-RK,and tc-PR

The guidelines to constitute a database containing, for 1800 pure fluids, more than 300,000 pseudo-experimental vapor pressure, liquid density, enthalpy of vaporization, and liquid heat capacity data are described. Such a database provides a tool for a fair assessment of the performances of equations of state to correlate (or predict) the properties of pure components. In this paper, we use it to assess the performance of four cubic equations of state (CEoSs): original Soave–Redlich–Kwong (SRK), original Peng–Robinson (PR), and the translated-consistent versions of PR (tc-PR) and RK (tc-RK). The deviations between calculated and experimental data are compared for the four CEoSs, which make it possible to discuss the influence of the α-function on the calculated vapor–liquid equilibrium properties and how the volume translation impacts the calculated volumetric properties. Eventually, the 1800 pure components are divided into 1252 non-self-associating and 548 self-associating compounds, and the accuracy of the CEoSs depending on the associating character of the molecules is discussed.     

Identifying Small‐Molecule Binding Sites for Epigenetic Proteins at Domain–Domain Interfaces

Epigenetics is a rapidly growing field in drug discovery. Of particular interest is the role of post‐translational modifications to histones and the proteins that read, write, and erase such modifications. The development of inhibitors for reader domains has focused on single domains. One of the major difficulties of designing inhibitors for reader domains is that, with the notable exception of bromodomains, they tend not to possess a well‐enclosed binding site amenable to small‐molecule inhibition. As many of the proteins in epigenetic regulation have multiple domains, there are opportunities for designing inhibitors that bind at a domain–domain interface which provide a more suitable interaction pocket. Examination of X‐ray structures of multiple domains involved in recognising and modifying post‐translational histone marks using the SiteMap algorithm identified potential binding sites at domain–domain interfaces. For the tandem plant homeodomain–bromodomain of SP100C, a potential inter‐domain site identified computationally was validated experimentally by the discovery of ligands by X‐ray crystallographic fragment screening.     

Efficient Permeability Measurement and Numerical Simulation of the Resin Flow in Low Permeability Preform Fabricated by Automated Dry Fiber Placement

We propose a new experimental method using a Hassler cell and air injection to measure the permeability of fiber preform while avoiding a race tracking effect. This method was proven to be particularly efficient to measure very low through-thickness permeability of preform fabricated by automated dry fiber placement. To validate the reliability of the permeability measurement, the experiments of viscous liquid infusion into the preform with or without a distribution medium were performed. The experimental data of flow front advancement was compared with the numerical simulation result using the permeability values obtained by the Hassler cell permeability measurement set-up as well as by the liquid infusion experiments. To address the computational cost issue, the model for the equivalent permeability of distribution medium was employed in the numerical simulation of liquid flow. The new concept using air injection and Hassler cell for the fiber preform permeability measurement was shown to be reliable and efficient.     

Refinement of international recommendations for cubicles,based on the identification of associations between cubicle characteristics and dairy cow welfare measures

Maladjusted cubicles for dairy cattle may cause increased skin alterations, lameness, and dirtiness. The International Commission of Agricultural and Biosystems Engineering has produced several recommendations for cubicle design, but a previous study showed that not all of them seem efficient. Here, we aim to refine and complete these recommendations. We collected data on 76 dairy farms (2,404 cows). We modeled the association between combinations of cubicle properties (e.g., type of bedding litter) and dimensions (e.g., cubicle width) relative to cow size, and prevalence of cow skin alterations, lameness, and dirtiness. We used weighted multivariable logistic regression models to predict the presence of skin alteration on the carpus; the neck, shoulder, and back; the flank, side, and udder; and the tarsus or hindquarters. We also evaluated the presence of lameness as well as the dirtiness of the lower hind legs including hocks; the hindquarters, upper hind legs, and flank; the cow rear including tail; and the udder. The risk factors highlighted led us to recommend (1) position cubicles in a way that leaves more than 1 m of clearance from any obstacle in front of the cubicle; (2) if there is an obstacle on the lateral plane (i.e., where the cubicle partition is) in front ahead of the cow, put the obstacle in front of the fore knees; (3) if there is an obstacle in front of the cow on the median plane (e.g., neck or front rail), the position the obstacle between 1.25 and 1.5 of the cow length from the curb and between 1.0 and 1.25 of its height; (4) use curb height between 0.11 and 0.15 of cow height with no sharp edges on the curb; (5) use round or at least has no sharp edges brisket board; (6) use a stone-free soil instead of concrete or use a mattress thicker than 1 cm, with microrelief, and a soft fixing area at the curb, (7) litter with straw (rather than nothing or sawdust) and keep it dry. This risk factor analysis should be followed by experiments in controlled environments to further validate these conclusions and used to update the International Commission of Agricultural and Biosystems Engineering recommendations.     

Padé approximants and the modal connection: Towards increased robustness for fast parametric sweeps

To increase the robustness of a Padé‐based approximation of parametric solutions to finite element problems, an a priori estimate of the poles is proposed. The resulting original approach is shown to allow for a straightforward, efficient, subsequent Padé‐based expansion of the solution vector components, overcoming some of the current convergence and robustness limitations. In particular, this enables for the intervals of approximation to be chosen a priori in direct connection with a given choice of Padé approximants. The choice of these approximants, as shown in the present work, is theoretically supported by the Montessus de Ballore theorem, concerning the convergence of a series of approximants with fixed denominator degrees. Key features and originality of the proposed approach are (1) a component‐wise expansion which allows to specifically target subsets of the solution field and (2) the a priori, simultaneous choice of the Padé approximants and their associated interval of convergence for an effective and more robust approximation. An academic acoustic case study, a structural‐acoustic application, and a larger acoustic problem are presented to demonstrate the potential of the approach proposed.