Transformations of (14C-lignin) cell walls of wheat by rumen microorganisms

The lower halves of apical internodes of wheat harvested at the flowering stage were labelled with [U-¹⁴C] phenylalanine (phe) or with [O¹⁴CH₃] sinapic acid (sin). Cell wall residues (CWR) and saponified residues (SR) were incubated in a fermenter simulating the rumen for 7 days with rumen fluid or without microorganisms (controls). PheCWR was labelled in all lignin units (measured as aldehydes from nitrobenzene oxidation), in phenolic acids and slightly in proteins. Labelling of pheSR was more lignin-specific. SinCWR and sinSR were specifically labelled in syringyl units of lignin. The fermentation of CWR resulted in phenylpropane-derived unit losses in the following decreasing order: ferulic acid>p-coumaric acid>syringaldehyde>vanillin>p-hydroxybenzaldehyde. If allowance is made for slight losses in controls, 61, 52, 61 and 63% of the phenylpropanes of pheCWR, sinCWR, pheSR and sinSR, respectively, were transformed into an acid-precipitable fraction, an acid-soluble fraction and ¹⁴CO_2. The comparison of pheCWR and sinCWR degradation showed that syringyl units were solubilised into acid-precipitable molecules to a greater extent than the other lignin units; demethylation of the syringyl units of lignins was also evident from the different productions of ¹⁴CO₂. Alkali-resistant lignins of SR were mainly transformed into acid-precipitable molecules and were weakly degraded. Lignin solubilisation and degradation seem to be governed by different mechanisms which depend on both cell wall structure and rumen microflora.     

Why are some texts good and others not? Relationship between text quality and management of the writing processes.

Two experiments examined whether text quality is related to online management of the writing processes. Experiment 1 focused on the relationship between online management and text quality in narrative and argumentative texts. Experiment 2 investigated how this relationship might be affected by a goal emphasizing text quality. In both experiments, psychology students were instructed to think aloud while composing their texts. Reaction times to auditory probes were also collected to reflect writers' cognitive effort. Two sets of variables were measured: general temporal indicators (fluency, prewriting pause) and online management of writing processes (number, mean length of episodes). Finally, text quality was assessed. As expected, results confirmed that narrative and argumentative texts are composed using different strategies. Students also composed better texts when a quality-based goal had been set. The main reliable indicator of text quality was an increase of the prewriting pause and of planning processes. These findings indicate that writers tailor their writing behavior to match the type and quality of the text they are asked to produce. These results are discussed in the light of interventions and recommendations in the classroom. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Thermal and refining processes, not fermentation, tend to reduce lipotropic capacity of plant-based foods

Plant-based foods (PBF) are relevant and diversified sources of lipotropes, which are compounds preventing excess hepatic fat deposits. In a first study, we defined the lipotropic capacity (LC, %) of raw PBF as the means of 8 lipotrope densities (LD, mg/100 kcal), each expressed relative to that of a reference food ranking the highest considering its mean 8 LD ranks (LC(raw asparagus)=100%) (A. Fardet, J.-F. Martin and J. M. Chardigny, J. Food Comp. Anal., 2011, DOI: 10.1016/j.jfca.2011.1003.1013). We showed that vegetables appeared as the best source of lipotropes on a 100 kcal-basis compared to legumes, cereals, fruits and nuts. The main objective of this second study was to quantify the effect of processing on LD and LC of raw PBF based on lipotrope contents collected in a USDA (United State Department of Agriculture) database and the literature, i.e. betaine, choline, myo-inositol, methionine, magnesium, niacin, pantothenic acid and folate contents. Choline and betaine densities were not significantly affected by processing while methionine and lipotropic micronutrient densities were significantly decreased, especially for magnesium, pantothenate and folates. Myo-inositol density decreases were insignificant due to lower product number resulting from limited literature data. Lipotropic micronutrient densities were more affected by processing than other densities. Fermentations increased betaine (median change of +32%) and choline (+34%) densities. Canning and boiling vegetables increased choline densities (+26%). Globally, processing significantly reduced LC by ～20%, fermentations being less drastic (median change of -5%) than refining (-33%) and thermal treatments (-16%). More specifically, canning increased LC of beetroot (536 vs 390%) and common bean (40 vs 36%) as fermentation towards LC grape (14 vs 7% for wine). Results were then mainly discussed based on percentages of lipotrope content changes on a dry-weight basis. Results of this study also showed that the LC is quite a relevant index to estimate effect of processing on lipotropic potential of PBF.     

REVISITING “SUBSISTENCE CRISES”: THE CHARACTERISTICS OF DEMOGRAPHIC CRISES IN FRANCE IN THE FIRST HALF OF THE 19TH CENTURY 1

According to traditional accounts, France underwent a serious crisis in 1846. Although it has never really been proven, it is held that the crisis was due to an enormous deficit in agricultural production. The study of price fluctuations, where price increases are taken to be proportional to production deficits, has led to the characterization of this crisis as a subsistence crisis. Certain historians have even noted strong demographic repercussions, in particular an increase in mortality. This article proposes to reassess the importance of this crisis. It also re-examines the different economic and demographic variables and the relationships between them at a national and regional level. In fact, as far as the demographics are concerned, this crisis turned out to be of a low magnitude, particularly when compared to the crises resulting from cholera in the 1830s. This first observation leads to an assessment of the real importance of production deficits. Contrary to the famines of the end of the 17th century, this crisis, although labelled a subsistence crisis, is characterized by a rather low deficit in cereal production. Substitutes such as potatoes, buckwheat, maize, and imports limited the effect of the crisis. As far as price increases are concerned, they appear to be non-proportional to production deficits: the two variables are not correlated.     

Modeling heat transfer for disinfestation and control of insects (larvae and eggs) in date fruits

A space-and-time dependent model describing the impact of heat transfer on insect survival rate was developed for analyzing the heat disinfestation process of dates. A 2D axial-symmetric domain was defined with five sub-domains: the bulk date pulp, a thin air layer and the date pit, a larva (located in the air layer) and eggs (on the date surface). The model included convective heating and microwave heating (915 MHz). Dielectric properties of the date pulp, egg and larvae were measured. The model predictions showed good agreement with experimental results in the case of the “biological model” (Ephestia kuehniella Zeller) in dates subjected to hot air treatment (70 °C). Sensitive analysis showed that the date size and water content greatly affected the heating time process, during hot air and microwave treatments. Moreover, regarding the eggs’ specific surface, it is advisable to combine convective hot air with microwave heating to induce egg mortality on the date surface.     

An investigation on thermal, metallurgical and mechanical states in weld cracking of Inconel 738LC superalloy

The influence of various conditions of Inconel 738 superalloy welding or deposition welding has been studied in order to shed light on the coupling between thermal, metallurgical and mechanical states in the heat affected zone (HAZ) in which cracking may occur particularly during welding and post-weld heat treatment. Predominant crack controlling factors have been highlighted thanks to different pre-weld and post-weld heat treatments, in addition to various welding rates and pre-heating prior to welding. These factors are mainly the material ductility related to the morphology and volume fraction of intermetallic precipitates and thermally induced residual stress. It has appeared that reducing thermally induced residual stress could be more effective for preventing cracking than controlling the material ductility in the related zones thanks to adjustment of pre-weld and post-weld heat treatments. With the objective of cracking remediation, welding on preheated parts leads to lower weld power, to reduce significantly thermal gradients, decreases thermally induced stress and impedes cracks formation despite some localized and temporary decrease in alloy ductility.     

Dispersion of odorous gases in the atmosphere - Part I: Modeling approaches to the phenomenon

The study of odor dispersion, particularly its modeling, is an important decision tool for estimating the impact of human activities on the environment and its populations. In this sense, software to model the dispersion of odorous gases was developed and is presented. It is based on the theory established by H?gstr?m on the odor dispersion of puff emissions. This theory is applied to Gaussian models and takes the frequency of values for odor intensity over any time period into account. Such a model is able to consider the instantaneous characteristics of odor perception by human beings. Nine approaches that explore several solutions within the Gaussian domain for the atmospheric dispersion problem are proposed in software named ODODIS (ODOr DISpersion Software). This software was developed to test the different solutions. Four of these solutions are based on the punctual (or point source) emission or classic equation; two are based on the instantaneous punctual emission equation; and the other three, on the prolonged punctual emission equation (puff models). Measuring units used for the input data may be g s(-1) or OU (Odor Units). The software developed here satisfies the need to obtain instantaneous data of either a passive or an odorous gas at a specific point of an area. The simulation time varies depending on the purpose of the analysis. Mean concentration values may be obtained by integrating the instantaneous results generated by the model.     

p27kip1 Modulates the Morphology and Phagocytic Activity of Microglia

p27^kip1 is a multifunctional protein that promotes cell cycle exit by blocking the activity of cyclin/cyclin-dependent kinase complexes as well as migration and motility via signaling pathways that converge on the actin and microtubule cytoskeleton. Despite the broad characterization of p27^kip1 function in neural cells, little is known about its relevance in microglia. Here, we studied the role of p27^kip1 in microglia using a combination of in vitro and in situ approaches. While the loss of p27^kip1 did not affect microglial density in the cerebral cortex, it altered their morphological complexity in situ. However, despite the presence of p27^kip1 in microglial processes, as shown by immunofluorescence in cultured cells, loss of p27^kip1 did not change microglial process motility and extension after applying laser-induced brain damage in cortical brain slices. Primary microglia lacking p27^kip1 showed increased phagocytic uptake of synaptosomes, while a cell cycle dead variant negatively affected phagocytosis. These findings indicate that p27^kip1 plays specific roles in microglia.     

Dispersion of graphite flakes into boehmite sols for the preparation of bi-layer-graphene / alumina coatings on stainless steel for tribological applications

Carbon-alumina coatings on stainless steel were prepared by a sol-gel route. The dispersion of the commercial graphite flakes by an ultrasonic bath, an ultrasonic probe and a high-shear mixer, produce thinner flakes, few-layered-graphene and bi-layer-graphene (BLG), respectively. The coatings were examined by optical and electron microscopy, interferential rugosimetry, optical profilometry and Raman spectroscopy. The friction coefficient against a steel ball is decreased by a factor of 5–7 and the wear volume is reduced by a factor of 6–38 compared to a pure alumina coating. The best results correspond to the sample prepared using the high-shear mixer. Delamination of the graphite flakes into BLG during the friction test provides the system with debris suitable for tribofilm building up and lubrication but it is better to already have carbon dispersed as BLG in the coating before the test, notably because the carbon surface area available is much higher.