Links between particle surface hardening and rehydration impairment during micellar casein powder storage

Storage is an unavoidable critical phase regarding dairy powder reconstitution abilities, particularly for high casein content powders, which generally present a poor rehydration behavior. The ability of micellar casein powders to completely rehydrate can thus be particularly affected by storage time and temperature. To implement best practices for the optimization of storage conditions, understanding changes occurring is a crucial point. For the first time, biophysical techniques were used to investigate powder surface at the nanoscale. Atomic force microscopy revealed that particle surface became rougher during storage, associated with the formation of hollow zones (around 500 nm) holes when stored for 10 months at 40 °C. Mechanical properties of micellar casein particle surface during powder storage was quantified using AFM nanoindentation. Spatially-resolved force/indentation curves evidenced a significant stiffer surface for aged powder (Young modulus of ∼20 GPa) in comparison with the fresh one (∼0.2 GPa). These findings were fully consistent with the formation of a crust at the powder surface observed by high-resolution field-emission scanning electron microscopy during powder rehydration. Finally, alterations of the rehydration process can be related to modifications occurring at the particle surface during storage

On the Experiments about the Nonprehensile Reconfiguration of a Rolling Sphere on a Plate

A method to reconfigure in a nonprehensile way the pose (position and orientation) of a sphere rolling on a plate is proposed in this letter. The nonholonomic nature of the task is first solved at a planning level, where a geometric technique is employed to derive a Cartesian path to steer the sphere towards the arbitrarily desired pose. Then, an integral passivity-based control is designed to track the planned trajectory. The port-Hamiltonian formalism is employed to model the whole dynamics. Two approaches to move the plate are addressed in this paper, showing that only one of them allows the full controllability of the system. A humanoid-like robot is employed to bolster the proposed method experimentally

Sensing and control of segmented mirrors with a pyramid wavefront sensor in the presence of spiders

The segmentation of the telescope pupil (by spiders & the segmented M4) create areas of phase isolated by the width of the spiders on the wavefront sensor (WFS), breaking the spatial continuity of the wavefront. The poor sensitivity of the Pyramid WFS (PWFS) to differential piston leads to badly seen and therefore uncontrollable differential pistons. In close loop operation, differential pistons between segments will settle around integer values of the average sensing wavelength. The differential pistons typically range from one to ten times the sensing wavelength and vary rapidly over time, leading to extremely poor performance. In addition, aberrations created by atmospheric turbulence will contain large amounts of differential piston between the segments. Removing piston contribution over each of the DM segments leads to poor performance. In an attempt to reduce the impact of unwanted differential pistons that are injected by the AO correction, we compare three different approaches. We first limit ourselves to only use the information measured by the PWFS, in particular by reducing the modulation. We show that using this information sensibly is important but will not be sufficient. We discuss possible ways of improvement by using prior information. A second approach is based on phase closure of the DM commands and assumes the continuity of the correction wavefront over the entire unsegmented pupil. The last approach is based on the pair-wise slaving of edge actuators and shows the best results. We compare the performance of these methods using realistic end-to-end simulations. We find that pair-wise slaving leads to a small increase of the total wavefront error, only adding between 20-45 nm RMS in quadrature for seeing conditions between 0.45-0.85 arcsec. Finally, we discuss the possibility of combining the different proposed solutions to increase robustness.Comment: 12 pages, 15 figures, AO4ELT5 Proceedings, Adaptive Optics for Extremely Large Telescopes 5, Conference Proceeding, Tenerife, Canary Islands, Spain, June 25-30, 201

Finding Needles in Haystacks: The Use of Quantitative Proteomics for the Early Detection of Colorectal Cancer

Colorectal cancer (CRC) is a common and treatable disease if diagnosed early. Current population screening programs are suboptimal, and consequently, there is a need for the development of new methodologies for early diagnosis of CRC. In the past 10 years, unprecedented technological advancements in the field of mass spectrometry (MS)-based proteomics have progressively increased the sophistication and utility of these investigations, leading to the draft mapping of the human proteome. These exciting studies have shaped our mechanistic understanding of the human genome and begun to provide us with a suite of novel biomarkers to predict the onset, progression and severity of many debilitating diseases. Thus, sophisticated MS workflows coupled with revolutionary protein quantification techniques hold promise for the field of MS-based plasma proteomics, particularly valuable in the context of early stage identification of curable CRC. However, within the last 40 years, no new plasma protein biomarkers of CRC have been translated into clinical practice. Here. we discuss the application of proteomic technologies within the field of CRC, highlighting contemporary MS-based plasma proteomic strategies that could be exploited to deliver on the promise of a panel of sensitive and specific plasma-based biomarkers with which to non-invasively detect early stage CRC

Temperature-dependent micromagnetic model of the antiferromagnet Mn2Au: A multiscale approach

Antiferromagnets (AFMs) are strong candidates for the future spintronic and memory applications largely because of their inherently fast dynamics and lack of stray fields, with Mn2Au being one of the most promising. For the numerical modeling of magnetic material properties, it is common to use ab initio methods, atomistic models, and micromagnetics. However, each method alone describes the physics within certain limits. Multiscale methods bridging the gap between these three approaches have been already proposed for ferromagnetic materials. Here we present a complete multiscale model of the AFM Mn2Au as an exemplar material, starting with results from ab initio methods going via atomistic spin dynamics (ASD) to an AFM Landau-Lifshitz-Bloch (AFM-LLB) model. First, bulk Mn2Au is modelled using a classical spin Hamiltonian constructed based on earlier first-principles calculations. Second, this spin model is used in the stochastic Landau-Lifshitz-Gilbert to calculate temperature-dependent equilibrium properties, such as magnetization and magnetic susceptibilities. Third, the temperature-dependent micromagnetic parameters are used in the AFM-LLB. We validate our approach by comparing the ASD and AFM-LLB models for three paradigmatic cases: (i) damped magnetic oscillations, (ii) magnetization dynamics following a heat pulse resembling pump-probe experiments, and (iii) magnetic domain wall motion under thermal gradients

Attenuation of RNA polymerase II pausing mitigates BRCA1-associated R-loop accumulation and tumorigenesis.

Most BRCA1-associated breast tumours are basal-like yet originate from luminal progenitors. BRCA1 is best known for its functions in double-strand break repair and resolution of DNA replication stress. However, it is unclear whether loss of these ubiquitously important functions fully explains the cell lineage-specific tumorigenesis. In vitro studies implicate BRCA1 in elimination of R-loops, DNA-RNA hybrid structures involved in transcription and genetic instability. Here we show that R-loops accumulate preferentially in breast luminal epithelial cells, not in basal epithelial or stromal cells, of BRCA1 mutation carriers. Furthermore, R-loops are enriched at the 5' end of those genes with promoter-proximal RNA polymerase II (Pol II) pausing. Genetic ablation of Cobra1, which encodes a Pol II-pausing and BRCA1-binding protein, ameliorates R-loop accumulation and reduces tumorigenesis in Brca1-knockout mouse mammary epithelium. Our studies show that Pol II pausing is an important contributor to BRCA1-associated R-loop accumulation and breast cancer development

Nouvelles méthodologies de caractérisation de la réactivité de surface de poudres alimentaires

National audienceCes dernières années, de nombreuses études ont porté sur la caractérisation des propriétés des poudres alimentaires, avec notamment comme objectif la prédiction et le contrôle de ces fonctionnalités. Auparavant, la plupart des études attribuaient les propriétés fonctionnelles à la composition globale de la poudre, alors que de récents travaux ont démontré un lien fort entre fonctionnalités et propriétés de surface. abSTRacT As the food powder production increases more and more it is the time to use new and innovative methodologies to understand the behavior of these powders regarding their functional properties. It was recently demonstrated that many functional properties (such as rehydration, caking, flowability, sticking…) were influenced not only by the particle bulk properties but also the particles surface properties. This chapter presents a number of methodologies in order to better characterize powder particle surfaces. Some of them are now well developed and often used by researchers and food industries. Nevertheless, others are less known but may be very promising in the future. Abréviations : Il semblait donc essentiel de développer de nouvelles méthodologies permettant de caractériser la surface des poudres. C'est ainsi que des approches ont été développées (Figure 1) à différentes échelles d'observation : atomique, moléculaire et microstructurale. A l'échelle atomique, la complémentarité des techniques XPS (Spectroscopie des Photons X) et EDX (Energie Dis-persive des rayons X) s'est révélée intéressante pour sonder la surface des poudres à différentes profondeurs (Figure 2). L'XPS permet ainsi de caractériser la composition atomique de l'extrême surface (≈ 5-10 nm) d'une poudre sur une aire assez importante (700 µm x 300 µm). A l'inverse, l'EDX per-met d'explorer les matrices alimentaires plus en profondeur (≈ 1-5 µm) et sur une surface plus étroite (5 µm²). Il a ainsi été mis en évidence que les poudres laitières, de par leur procédé d'obtention (séchage par atomisation), pré-sentaient des gradients de composition entre la surface et le coeur des particules. D'une manière générale, les protéines et les lipides sont surreprésentés en surface, alors que le lactose et les minéraux sont plutôt localisés au coeur de la particule. En revanche, la surface est plutôt homogène, quelle que soit la zone analysée. De plus, il a été observé une répartition différente des consti-tuants dans les poudres céréalières. Les différences de composition entre surface et coeur des particules sont moins marquées, tandis que la distribution des composants en surface est fortement hétérogène. Figure 1. Approche multi-échelle (de l'atome à la microstructure) permettant de caractériser la surface d'une poudre alimentaire

Ultraviolet Signposts of Resonant Dynamics in the Starburst-Ringed Sab Galaxy, M94 (NGC 4736)

M94 (NGC 4736) is investigated using images from the Ultraviolet Imaging Telescope (FUV-band), Hubble Space Telescope (NUV-band), Kitt Peak 0.9-m telescope (H-alpha, R, and I bands), and Palomar 5-m telescope (B-band), along with spectra from the International Ultraviolet Explorer and Lick 1-m telescopes. The wide-field UIT image shows FUV emission from (a) an elongated nucleus, (b) a diffuse inner disk, where H-alpha is observed in absorption, (c) a bright inner ring of H II regions at the perimeter of the inner disk (R = 48 arcsec. = 1.1 kpc), and (d) two 500-pc size knots of hot stars exterior to the ring on diametrically opposite sides of the nucleus (R= 130 arcsec. = 2.9 kpc). The HST/FOC image resolves the NUV emission from the nuclear region into a bright core and a faint 20 arcsec. long ``mini-bar'' at a position angle of 30 deg. Optical and IUE spectroscopy of the nucleus and diffuse inner disk indicates an approximately 10^7 or 10^8 yr-old stellar population from low-level starbirth activity blended with some LINER activity. Analysis of the H-alpha, FUV, NUV, B, R, and I-band emission along with other observed tracers of stars and gas in M94 indicates that most of the star formation is being orchestrated via ring-bar dynamics involving the nuclear mini-bar, inner ring, oval disk, and outer ring. The inner starburst ring and bi-symmetric knots at intermediate radius, in particular, argue for bar-mediated resonances as the primary drivers of evolution in M94 at the present epoch. Similar processes may be governing the evolution of the ``core-dominated'' galaxies that have been observed at high redshift. The gravitationally-lensed ``Pretzel Galaxy'' (0024+1654) at a redshift of approximately 1.5 provides an important precedent in this regard.Comment: revised figure 1 (corrected coordinate labels on declination axis); 19 pages of text + 19 figures (jpg files); accepted for publication in A

Fetal Lead Exposure at Each Stage of Pregnancy as a Predictor of Infant Mental Development

BACKGROUND: The impact of prenatal lead exposure on neurodevelopment remains unclear in terms of consistency, the trimester of greatest vulnerability, and the best method for estimating fetal lead exposure. OBJECTIVE: We studied prenatal lead exposure’s impact on neurodevelopment using repeated measures of fetal dose as reflected by maternal whole blood and plasma lead levels. METHODS: We measured lead in maternal plasma and whole blood during each trimester in 146 pregnant women in Mexico City. We then measured umbilical cord blood lead at delivery and, when offspring were 12 and 24 months of age, measured blood lead and administered the Bayley Scales of Infant Development. We used multivariate regression, adjusting for covariates and 24-month blood lead, to compare the impacts of our pregnancy measures of fetal lead dose. RESULTS: Maternal lead levels were moderately high with a first-trimester blood lead mean (± SD) value of 7.1 ± 5.1 μg/dL and 14% of values ≥10 μg/dL. Both maternal plasma and whole blood lead during the first trimester (but not in the second or third trimester) were significant predictors (p < 0.05) of poorer Mental Development Index (MDI) scores. In models combining all three trimester measures and using standardized coefficients, the effect of first-trimester maternal plasma lead was somewhat greater than the effect of first-trimester maternal whole blood lead and substantially greater than the effects of second- or third-trimester plasma lead, and values averaged over all three trimesters. A 1-SD change in first-trimester plasma lead was associated with a reduction in MDI score of 3.5 points. Postnatal blood lead levels in the offspring were less strongly correlated with MDI scores. CONCLUSIONS: Fetal lead exposure has an adverse effect on neurodevelopment, with an effect that may be most pronounced during the first trimester and best captured by measuring lead in either maternal plasma or whole blood