Microradiography as a tool to detect heavy metal uptake in plants for phytoremediation applications

In this paper, an application of contact microradiography with soft X-rays for detecting the uptake site of heavy metal in the whole plant leaves is investigated. The X-ray source is a laser-plasma one based on an Nd:glass laser. The soft X-ray radiation emitted from the plasma laser targets of magnesium, iron, and copper can be strongly absorbed in the leaves' regions rich in iron, magnesium, and copper. This absorbance could point to structures in the leaves where these heavy elements are found. In this work, leaves treated with copper sulfate diluted in water at 1, 2, and 5% were imaged by using a copper target, in order to evaluate differences with untreated control leaves. Our results showed that this methodology highlighted the presence of copper in the treated leaves. This new methodology should detect heavy element pollutants inside plants and it should also be a useful analytic tool in phytoremediation studies.     

Immunohistochemical detection and quantification of T cells in the small intestine of Isospora suis-infected piglets--influence of fixation technique and intestinal segment

Quantification of immunohistochemical results constitutes an important tool in the analysis of cells and tissue that is not readily replaced by other techniques. For reliable quantification, it is essential to consider factors such as tissue fixation and tissue sampling. We report a study on the model of the intestine of Isospora suis‐infected piglets, in which we addressed (1) whether the quantity of detectable T cells in the intestinal mucosa is the same in formalin‐, HOPE®‐, and cryo‐conserved material or whether the amounts of T cells at least correlate with one another; and (2) whether single jejunal segments differ in regard to the quantity of mucosal T cells and variability of lymphocyte infiltration. Quantification of T cells in histological sections of different parts of the jejunum of 15‐22 day old piglets infected with I. suis was performed using an anti‐CD3‐antibody and stereological point counting. Area fractions of T‐cell profiles per intestinal mucosa profile were higher in cryo‐conserved samples than in HOPE®‐ and formalin‐conserved material but no correlation between different fixations could be found. The proximal part of the jejunum contained fewer T cells compared with mid‐ and end‐jejunum. Coefficients of variation did not differ between the intestinal segments. For quantification of T cells in the gut mucosa of piglets infected with I. suis, the cryo‐conserved mid jejunum seems most suitable in cases when unbiased sampling of the complete intestine is not feasible. It is generally not possible to compare quantitative results of immunostaining in samples conserved by different methods. Microsc. Res. Tech., 2011. © 2011 Wiley‐Liss, Inc.     

Three months of Western diet induces small intestinal mucosa alteration in TLR KO mice

Several studies support the role of Western‐style diet (WD) in inflammatory bowel disease (IBD). Toll‐like receptors/NOD‐like receptors (TLRs/NLRs) are important to maintain a healthy epithelium as well as inducing inflammation. Given that dietary factors influence IBD development, that epithelial dysfunction is thought to be involved in initiating intestinal inflammation and that TLR‐NLR are involved in maintenance of the functionality of intestinal epithelium as well as in regulating inflammation, we decided to examine the role of TLR signals in the triggering events that lead to alteration of the small intestinal epithelium associated to consumption of WD. C57BL/6J mice deficient for TLR2, 4, 9, or NOD2 and wild‐type (WT) were fed a WD or a standard diet for 3 months. The effects of WD on small intestinal samples were evaluated by histological and immunohistochemical analysis. After 3 months, WD modifies the morphology and the organization of the small intestine in TLR9 KO mice compared with WT mice and the others TLRs. The most interesting change involved the expression of proliferative and differentiation markers of WNT signaling, Ki67 and FzD5. Mice deficient in TLR2, 4, and NOD2 have a significant reduction in the proliferative cell numbers but do not show any signs of histological alterations. Our results suggest that TLR9 is an important protective factor in intestinal epithelial homeostasis and provide new insights into an unrecognized role of TLR9 signaling in the small intestinal mucosa dysfunction associated with WD.     

Highly thermostable and crystalline poly(butylene adipate) bionanocomposites prepared by in situ polycondensation with organically modified Moroccan beidellite clay

Bionancomposites from bioplastics and nanoclays are of great interest for packaging, agricultural and other large‐volume and niche applications due to their enhanced physical, thermal, mechanical and processing characteristics compared to the parent polymer. In this study, the biodegradable polyester poly(butylene adipate) (PBA ) was synthesized by in situ polycondensation catalysed by titanium tetrabutoxide in the presence of the natural Moroccan clay beidellite (BDT ). Optimization of the nanoclay exfoliation in the bionanocomposite was achieved by cation exchange of BDT with cetyltrimethylammonium bromide (CTA ) and by selecting the most effective among a range of organically modified x CTA‐BDT (x = CTA/BDT equivalent feed ratio). Fourier transform infrared and ¹H NMR spectral and size exclusion chromatographic analyses confirmed the effectiveness of the in situ polymerization, yielding structurally regular PBA with narrow molecular weight dispersity and 7750 < < 30 360 g mol^?1, depending on the organoclay load. X‐ray diffraction and transmission electron microscopy analyses showed best clay dispersion and homogeneous distribution at 2 wt% 3CTA‐BDT. From thermogravimetric analysis and differential scanning calorimetry results the thermal stability of PBA is greatly improved even at 1 wt% 3CTA‐BDT, its glass transition temperature is nearly unaffected while crystallinity is increased by the organoclay nucleating action. These results, along with a bionanocomposite hydrophilicity only moderately higher than that of PBA, make this preparation approach particularly promising. © 2017 Society of Chemical Industry     

Qualitative detection of Mg content in a leaf of Hedera helix by using X-ray radiation from a laser plasma source

In this article, a method to reveal the presence of Mg content inside the different parts of leaves of Hedera helix is presented. In fact a sample of a Hedera helix's leaf, commonly characterized by a green and a white side, is analyzed under X-ray radiation. The presence of two zones with different colors in the Hedera helix's leaf has not been explained. In this connection, there are presently three hypotheses to explain the characteristic double-color appearance of the leaf. The first hypothesis suggests a different cytoplasmic inheritance of chloroplasts at the cell division, the second a different allelic composition, homozygote and heterozygote, between the two zones, and finally the third the action of a virus which changes the color properties in the Hedera's leaves. The resulting effect is a different content of "something" between the green and the white side. We utilized X-ray radiation, obtained from a plasma source with a Mg target, to image Hedera helix leaves and we found that the green side of the leaf is highlighted. We may suppose that the reason why the X-rays from a Mg plasma source, allow us to pick up the green side is probably due to the greater presence of the amount of Mg (from chlorophyll or other complexes and/or salts) in the two sides, green and white, of the leaf.     

Enhancing post-classification change detection through morphological post-processing – a sensitivity analysis

Monitoring land-cover change is often done by simple overlay of two classified maps from different dates. However, such analysis tends to overestimate the rate of change. Main error sources are the mis-registration between classified maps and their thematic accuracies. This study proposes a change detection method with morphological post-processing to improve change detection accuracy in comparison with traditional post-classification by taking into account these error sources. The method is developed for binary maps and is based on standard morphological procedures that are generally integrated in common spatial processing or free software. A detailed sensitivity analysis of this method based on simulated data sets of different landscape characteristics and error levels demonstrated the potential improvement. The degree of improvement in change detection accuracy mainly depended on the error type and level and the fragmentation of the landscape. In particular, location error effects on change detection were strongly reduced independent of class proportion. Up to 60% improvement in user's accuracy of change could be achieved for maps with location error and characterized by fragmented landscapes. Coping with classification errors was shown to be more challenging. A user-friendly reference table summarizes the potential improvement through the proposed methods for various landscape characteristics and error sources.     

A face recognition system based on Pseudo 2D HMM applied to neural network coefficients

Face recognition from an image or video sequences is emerging as an active research area with numerous commercial and law enforcement applications. In this paper different Pseudo 2-dimension Hidden Markov Models (HMMs) are introduced for a face recognition showing performances reasonably fast for binary images. The proposed P2-D HMMs are made up of five levels of states, one for each significant facial region in which the input frontal images are sequenced: forehead, eyes, nose, mouth and chin. Each of P2-D HMMs has been trained by coefficients of an artificial neural network used to compress a bitmap image in order to represent it with a number of coefficients that is smaller than the total number of pixels. All the P2-D HMMs, applied to the input set consisting of the Olivetti Research Laboratory face database combined to others photos, have achieved good rates of recognition and, in particular, the structure 3-6-6-6-3 has achieved a rate of recognition equal to 100%.     

Structural investigation of the HIV-1 envelope glycoprotein gp160 cleavage site 3: role of site-specific mutations

Proteolytic processing of HIV gp160 to produce gp120 and gp41 is performed by PC enzymes. This process is a prerequisite for the virus infectivity, since both gp120 and gp41 participate in the virus HIV-1 entry mechanism. The structure of the gp120/gp41 junction remains to be elucidated, and the structural features required for molecular recognition between HIV-1 gp160 and proteolytic enzymes have not been clarified. Furin is the best PC candidate for the gp160 proteolytic processing known to date.In previous studies on model peptides, we have shown the relevance of an N-terminal helix for the proper recognition of the gp160 processing site by furin. Here we analyze the effect of point mutations in peptides lacking a regular N-terminal helix. To this end, we present the structure-activity characterization of three peptide analogues of the HIV gp160 processing site that all present mutations in proline at positions P3 and/or P2', while sharing the same N-terminal sequence, containing helix-breaking D-amino acids. Conformational analysis of the peptides was carried out in solution by NMR techniques, and furin's efficiency in cleaving them was measured. Structural findings are presented and discussed in relation to the different exhibited activity.