Effects of chelates (EDTA, EDDS, NTA) on Phytoavailability of HMs (As, Cd, Cu, Pb, Zn) using Ryegrass (Lolium multiflorum)

This paper summarises a study of the application of the synthetic chelate ethylenediaminetetraacetic acid (EDTA), and the natural chelates ethylenediamine-N,N-disuccinic acid (EDDS) and nitrilotriacetate (NTA) to enhance ryegrass uptake of the heavy metal(oid)s (HMs) (As, Cd, Cu, Pb and Zn) from contaminated soils in mining sites. The study compares the effects of these chelates (EDTA, EDDS and NTA) on the phytoavailability of HMs (As, Cd, Cu, Pb, Zn) using ryegrass (Lolium multiflorum) through the single addition and sequential addition methods. The results show that application of EDTA, EDDS and NTA significantly increases ryegrass’s (Lolium multiflorum) shoot uptake of some HMs when compared with no EDTA, EDDS or NTA application, particularly through sequential chelate treatment (EDTA 0.5:1 + 0.5:1; NTA 0.5:1 + 0.5:1; EDDS 0.5:1 + 0.5:1). EDTA 0.5:1 + 0.5:1 was more effective at increasing the concentration of Pb in shoots than were the other chelates (EDDS and NTA) and controls. Moreover, the concentrations of Zn in the shoots of ryegrass in LH significantly increased with the application of split dose (0.5:1 + 0.5:1). The plants displayed symptoms of toxicity including yellow and necrotic leaves at the end of the experiment. The selected chelates (EDTA, EDDS and NTA) led to a significant decrease in plant biomass (yield) 28 days after transfer with a maximum decrease in EDTA treatment (0.5:1 + 0.5:1) soils. This decrease was 3.43-fold in HT, 3-fold in LH and 1.59-fold, respectively, relative to the control. HM concentration and dissolved organic carbon (DOC) in pore water, provided an explanation for why fresh weight was significantly reduced with application of chelates in sequential dose (EDTA 0.5:1 + 0.5:1 and NTA 0.5:1 + 0.5:1).

A Test of Two Methods for Waste Rock Drainage Quality Prediction: Aqua Regia Extraction and Single-addition Net-acid Generation Test Leachate Analysis

The mobility of contaminants from mine waste can be assessed using different extraction methods. Aqua regia (AR) extraction is the most commonly used method in Finland. Another method is the analysis of leachate from net acid generation (NAG) tests, which is primarily designed for acid production potential assessment. We investigated the performance of single-addition NAG test leachate analysis and AR extraction in drainage quality prediction, using waste rock and drainage water samples from several Finnish waste rock sites. Our objective was to improve interpretation of the AR and single-addition NAG test leachate analysis results in drainage quality prediction. The AR extraction effectively reflected elements that occurred in elevated concentrations in drainage water, though it over-predicted Al, As, Cd, Co, Cu, and Ni in some circumneutral drainages, and Cr in general. The single-addition NAG test leachate analysis also performed well in assessing the mobility of contaminants including Al and Cr at acid mine drainage sites. As the contaminants tend to precipitate in neutral NAG test solution, the usability of the method in neutral mine drainage cases should be further investigated. Furthermore, the conclusions presented in this study are limited to waste rock samples collected from the surface of piles; future work will examine waste rock history, dump cores, drainage quality changes, etc. in more detail.

Diels-Alder Additions to 2,2’-Biaceanthrylene

A series of Diels-Alder reactions between the diene 2,2’-biaceanthylene and several dienophiles is presented. The diene is a cyclopenta-fused polycyclic aromatic hydrocarbon with anthracene units linked by two cyclopentene rings. Depending on the dienophile, the major product was the result of a single addition (dimethyl acetylenedicarboxylate) or double addition (quinone, benzyne) to the diene. Single crystal X-ray analysis of the quinone-derivative shows a propeller-like structure composed of mixed enantiomers. The synthesis and photophysical properties of these compounds is presented.<br>

Diels-Alder Additions to 2,2’-Biaceanthrylene

A series of Diels-Alder reactions between the diene 2,2’-biaceanthylene and several dienophiles is presented. The diene is a cyclopenta-fused polycyclic aromatic hydrocarbon with anthracene units linked by two cyclopentene rings. Depending on the dienophile, the major product was the result of a single addition (dimethyl acetylenedicarboxylate) or double addition (quinone, benzyne) to the diene. Single crystal X-ray analysis of the quinone-derivative shows a propeller-like structure composed of mixed enantiomers. The synthesis and photophysical properties of these compounds is presented.<br>

Oxanorbornenes: Promising New Single Addition Monomers for the Metathesis Polymerization

Higher ring-opening metathesis propagation rates of exo-norbornene derivatives over endo derivatives are well established in the literature. Here, we report for the first time that endo-isomers of oxanorbornene derivatives show...

Dynamics of morphological changes in neural cell culture with a model of neurotrauma under the influence of conditioned media of the rat fetal brain neurogenic cells

A potential strategy for recovery and regeneration of brain damage due to traumatic brain injury is considered to be the transplantation of neurogenic stem and/or progenitor cells (NSCs/NPCs). The key factors of the regenerative non-targeted effects of NSCs/NPCs (so-called bystander effects) include the signal molecules produced by them into the extracellular environment (secretome). The purpose is to study the regenerative bystander effects of rat fetal brain neurogenic cells (FBNCs) in the in vitro model of neurotrauma. Materials and methods. In cell culture of FBNCs from rat fetuses (E14-16), neurotrauma was modeled in vitro by mechanical scratching of monolayer and conditioned medium obtained from 24-h cultures of rat FBNCs was added. Cell phenotype was evaluated by morphological features and by immunocytochemical staining for Nestin and GFAP. The density and length of processes, migration capacity, the cell growth rate and monolayer density in the scratched area were compared. Morphometric study included analysis of the width of the scratched area, the number of migrating cells, the distance of migration and mitotic activity in the intact monolayer. Results. Under the conditions of the nutrient medium of standard composition in the scratched area the signs of endogenous regeneration are shown during 24-48 h of cultivation. The overgrowth of cell processes from monolayer and short distance migration of single undifferentiated or poorly differentiated cells were shown. In the next 72-96 h of observation, the degeneration of migrated cells and processes in the scratched area was detected. Under the influence of conditioned media from 24-h cultures of FBNCs by single addition immediately after scratching at dose of 0.1 mg/ml for protein content the stimulation of regeneration were detected up to 96 hours of cultivation. The migration of cell processes from the monolayer simultaneously with undifferentiated or poorly differentiated cells at 24 hours was shown. The formation of cell clusters and their differentiation (at 48 h), as well as migration of differentiated cells with partial or complete overgrowth of scratched area (72-96 h) were observed. The morphological signs of degeneration of migrated cells in the scratched area appeared only on the 8th day of cultivation. Conditioned media does not affect qualitative and quantitative properties of the culture of rat FBNCs in the intact area where mitotic activity was average. Conclusions. Conditioned medium from 24-h cultures of rat FBNC can stimulate reparation in the in vitro model of neurotrauma in neural cell culture for at least 7 days at a single addition, without affecting the cellular composition and mitotic activity of the intact monolayer.

Effect of the Addition Frequency of 5-Azacytidine in Both Micro- and Macroscale Cultures

Introduction Human mesenchymal stem cells (hMSCs) have a great clinical potential for tissue regeneration purposes due to its multilineage capability. Previous studies have reported that a single addition of 5-azacytidine (5-AzaC) causes the differentiation of hMSCs towards a myocardial lineage. The aim of this work was to evaluate the effect of 5-AzaC addition frequency on hMSCs priming (i.e., indicating an early genetic differentiation) using two culture environments. Methods hMSCs were supplemented with 5-AzaC while cultured in well plates and in microfluidic chips. The impact of 5-AzaC concentration (10 and 20 μM) and addition frequency (once, daily or continuously), as well as of culture period (2 or 5 days) on the genetic upregulation of PPARγ (adipocytes), PAX3 (myoblasts), SOX9 (chondrocytes) and RUNX2 (osteoblasts) was evaluated. Results Daily delivering 5-AzaC caused a higher upregulation of PPARγ, SOX9 and RUNX2 in comparison to a single dose delivery, both under static well plates and dynamic microfluidic cultures. A particularly high gene expression of PPARγ (tenfold-change) could indicate priming of hMSCs towards adipocytes. Conclusions Both macro- and microscale cultures provided results with similar trends, where addition frequency of 5-AzaC was a crucial factor to upregulate several genes. Microfluidics technology was proven to be a suitable platform for the continuous delivery of a drug and could be used for screening purposes in tissue engineering research.

NMR Analysis of Poly(Lactic Acid) via Statistical Models

The physical properties of poly(lactic acid) (PLA) are influenced by its stereoregularity and stereosequence distribution, and its polymer stereochemistry can be effectively studied by NMR spectroscopy. In previously published NMR studies of PLA tacticity, the NMR data were fitted to pair-addition Bernoullian models. In this work, we prepared several PLA samples with a tin catalyst at different L,L-lactide and D,D-lactide ratios. Upon analysis of the tetrad intensities with the pair-addition Bernoullian model, we found substantial deviations between observed and calculated intensities due to the presence of transesterification and racemization during the polymerization processes. We formulated a two-state (pair-addition Bernoullian and single-addition Bernoullian) model, and it gave a better fit to the observed data. The use of the two-state model provides a quantitative measure of the extent of transesterification and racemization, and potentially yields useful information on the polymerization mechanism.