Uranium release from a natural rock under near-natural oxidizing conditions

Understanding how uranium (U) moves through the soil and groundwater is essential to determine the effectiveness of cleanup technologies. Uranium release and transport in the subsurface under oxic conditions have been reported to be mostly dependent on sorption onto Fe/Mn-oxide and complex interactions with organic substances. Available information in the literature however presents evidence of U retardation by natural sands. The aim of this investigation was to characterize U dissolution from a uraninite-containing rock (UO2-rock) in different waters under test conditions relevant to U transport from mine wastes (tailings). For this purpose, not shaken batch experiments were conducted with a constant amount of an UO2-rock and different types of water (deionised, tap and mineral water). For comparison parallel experiments were conducted with 0.1 M Na2CO3 and 0.1 M H2SO4. Further dissolution experiments using UO2-rock together with dolomite and pyrite were conducted. The results indicate that carbonate addition (soluble or in-situ generated) enhanced U solubilization, whereas pyrite addition essentially slowed the initial U solubilization. It is shown that SiO2 and other rock constituents may contribute to retard U transport.researc

Laboruntersuchungen zur Freisetzung von Unat aus einem Gestein unter oxischen naturnahen Bedingungen

The effects of carbonate concentration and the presence of iron hydroxide phases on uranium release into the environment were investigated under oxic conditions and in the pH range from 6 to 9. For this purpose not-shaken batch experiments were conducted with a constant amount (8, 10 or 40 g/l) of a uranium bearing rock and different types of water (deionised, tap and mineral water). For comparison parallel experiments were conducted with 0.1 M Na 2 CO 3 and 0.1 M H 2 SO 4 . The use of dolomite confirmed the favourable role of carbonate bearing minerals for U transport while the presence of pyrite on Uranium mobilisation was shown to be considerably more complex. This study shows that the approach of equilibrium conditions can be strongly delayed by sorption processes.researc

Macrocyclic tetramers—structural investigation of peptide-peptoid hybrids

Outstanding affinity and specificity are the main characteristics of peptides, rendering them interesting compounds for basic and medicinal research. However, their biological applicability is limited due to fast proteolytic degradation. The use of mimetic peptoids overcomes this disadvantage, though they lack stereochemical information at the α-carbon. Hybrids composed of amino acids and peptoid monomers combine the unique properties of both parent classes. Rigidification of the backbone increases the affinity towards various targets. However, only little is known about the spatial structure of such constrained hybrids. The determination of the three-dimensional structure is a key step for the identification of new targets as well as the rational design of bioactive compounds. Herein, we report the synthesis and the structural elucidation of novel tetrameric macrocycles. Measurements were taken in solid and solution states with the help of X-ray scattering and NMR spectroscopy. The investigations made will help to find diverse applications for this new, promising compound class

Macrocyclic Tetramers—Structural Investigation of Peptide-Peptoid Hybrids

Outstanding affinity and specificity are the main characteristics of peptides, rendering them interesting compounds for basic and medicinal research. However, their biological applicability is limited due to fast proteolytic degradation. The use of mimetic peptoids overcomes this disadvantage, though they lack stereochemical information at the α-carbon. Hybrids composed of amino acids and peptoid monomers combine the unique properties of both parent classes. Rigidification of the backbone increases the affinity towards various targets. However, only little is known about the spatial structure of such constrained hybrids. The determination of the three-dimensional structure is a key step for the identification of new targets as well as the rational design of bioactive compounds. Herein, we report the synthesis and the structural elucidation of novel tetrameric macrocycles. Measurements were taken in solid and solution states with the help of X-ray scattering and NMR spectroscopy. The investigations made will help to find diverse applications for this new, promising compound class

Wetting film dynamics and stability

Although the wetting films are similar in many aspects to other thin liquid films, there are some differences in their behavior, too. In contrast to soap and emulsion films, whose surfaces are homogeneous, solid substrates of wetting films are heterogeneous as a rule, unless special measures for their homogenization are taken. Here we mean primarily heterogeneous distribution of surface energy leading to existence of hydrophobic domains on hydrophilic surfaces and vice versa. As is known, such hydrophobic domains could play the role of gas-phase nucleation centers and it is widely accepted nowadays that nano-bubbles can be formed there. The present paper reviews the effect of nano-bubbles adhered at solid surface on stability of wetting films. It is shown that the existence of nano-bubbles is crucial for the lifetime of wetting films. Another peculiarity typical for hydrophobic solid surface, the so-called slippage effect, is also investigated and its contribution to the dispersion equation of capillary waves on wetting films is accounted for

Mannose 6-phosphate potentiates insulin-like growth factor II effects in cultured human neuroblastoma cells

Insulin-like growth factor II (IGF-II) and mannose 6-phosphate (man-6-P) bind to distinct sites on the same receptor4,16,20. In the present study, we examined the effects of man-6-P on the growth promoting effects of IGF-II on SH-SY5Y cultured human neuroblastoma cells. Man-6-P alone increased cell number and neurite outgrowth by approximately 50%; as previously observed12,18,27,30, IGF-II increased cell number and neurite outgrowth by approximately 110 and 30%, respectively. However, when cells were grown in the presence of both ligands, cell number increased by 330% and neurite outgrowth by 130%. These results suggest that man-6-P can potentiate the known growth promoting effects of IGF-II on human neuroblastoma cells. Furthermore, they indicate that the IGF-II/man-6-P receptor may serve as a means of integrating distinct growth promoting signals in neuronal cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29085/1/0000120.pd

Barriers to adoption of biogenic carbonates in the food, pharmaceutical & supplement sectors

There is an increasing demand for environmentally sustainable sourcing of ingredients for the food, pharmaceutical and supplements industries. In the case of calcium carbonate (E170) as by-products from the egg and shellfish processing industries these have the potential to be sustainably sourced. In addition to their green credentials, biogenic carbonates have intrinsic benefits in terms of their chemical composition, such as a low heavy metal burden. However, their biogenic origin can potentially lead to manufacturing issues such as higher levels of co-mineralising components and the organic templates of their natural production. This contribution identifies the regulatory barriers to the adoption of biogenic eggshell calcium carbonate by assessing materials from biological sources along with commercial precipitated and ground carbonates against current regulatory standards

Alpha interferon in the treatment of hematologic malignancies

The interferons are an important first member of a family of biologic response-modifiers used in treating human malignancies. Activities associated with the interferons include inhibition of viral replication, influence on cellular protein production, direct antiproliferative effects, and a variety of modulatory effects on the immune response. These regulatory functions of interferon underlie the interest in its use as an anticancer agent. Alpha interferon is the most extensively studied interferon species. Although antitumor activity has been seen both in vitro and in vivo in some solid malignancies, the most impressive responses have occurrred in the hematologic malignancies. More than 90 percent of patients with hairy cell leukemia have a sustained recovery of their peripheral blood cell counts with alpha interferon therapy. Approximately 50 percent of patients with low-grade non-Hodgkin's lymphoma and cutaneous T cell lymphoma demonstrate a response to alpha interferon. More than 80 percent of patients with chronic myelogenous leukemia have a response to alpha interferon, and in one study, nearly half of the patients with response had complete suppression of the Philadelphia chromosome clone on at least one examination. Ongoing clinical trials are addressing such issues as optimal dosage, duration of alpha interferon therapy, and combinations of alpha interferon with other biologic agents, chemotherapy drugs, and radiation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26440/1/0000528.pd

Measuring pH in low ionic strength glacial meltwaters using ion selective field effect transistor (ISFET) technology

Measuring pH in glacial meltwaters is challenging, because they are cold, remote, subject to freeze‐thaw cycles and have low ionic strength. Traditional methods often perform poorly there; glass electrodes have high drift and long response times, and spectrophotometric techniques are unpractical in cold, remote environments. Ion selective field effect transistor (ISFET) sensors are a promising alternative, proven in marine and industrial applications. We assess the suitability of two models of ISFET, the Honeywell Durafet and Campbell Scientific Sentron, for use in glacial melt through a series of lab and field experiments. The sensors have excellent tolerance of freeze‐thaw and minimal long‐term drift, with the Durafet experiencing less drift than the Sentron model. They have predictable response to temperature, although the Durafet housing causes some lag during rapid cycling, and the impact of stirring is an order of magnitude less than that of glass electrodes. At low ionic strength ( 7 with consistent diurnal cycles from the very first meltwater flows. We recommend that ISFET sensors are used to assess the pH of glacial meltwater, since their tolerance is significantly better than alternative methods: the Durafet is accurate to ± 0.2 pH when waters are > 1 mmol L−1 ionic strength, and ± 0.3 pH at < 1 mmol L−1

Chlorinated and brominated polycyclic aromatic hydrocarbons in ambient air: seasonal variation, profiles, potential sources, and size distribution

Chlorinated and brominated polycyclic aromatic hydrocarbons (ClPAHs and BrPAHs, respectively) are a new derivative group of PAHs. These halogenated PAHs (Halo-PAHs) have been reported to be carcinogenic and are considered emerging persistent organic pollutants. Gaining a clear understanding of the distribution and behavior of these ubiquitous organic pollutants is essential for the control and mitigation of their emission into the environment. However, research into the characteristics of Halo-PAHs in the atmosphere has been somewhat limited. This review paper thus aims to provide an overview of the seasonal patterns, profiles, potential sources, and particle-size distributions of atmospheric ClPAHs and BrPAHs with 3-5 rings. Most previous studies have focused on particulate Halo-PAHs and reported that their levels are higher during the cold season than during the warm season, with this seasonal variation more apparent for ClPAHs than for BrPAHs. In terms of their phase distribution, ClPAHs and BrPAHs share a similar trend, with their gaseous concentrations highest in summer and lowest in winter and their particulate concentrations exhibiting the opposite trend. Halo-PAH profiles have been shown to differ between sampling locations, possibly reflecting differences in the potential sources present at these sites, e.g., coal burning, traffic emissions, and industrial activity. The majority of Halo-PAHs tend to accumulate as ultrafine particles with an aerodynamic diameter of less than 1.0 mu m. Overall, a detailed understanding of the characteristics of Halo-PAHs in the atmosphere has yet to be achieved; hence, further research on atmospheric Halo-PAHs is necessary