Identifying Shared Environmental Contributions to Early Substance Use: The Respective Roles of Peers and Parents.

Although behavior genetic studies have suggested that early substance use is primarily environmentally mediated, no study has sought to identify the specific sources of environmental variance. Using data obtained from multiple informants, this study assessed the contributions of peer deviance and parent-child relationship problems to substance use in 14-year-old male and female twins (N = 1,403) drawn from the Minnesota Twin Family Study (MTFS). All three phenotypes were influenced primarily by shared environmental variance (average c2 = .51), as was the overlap among them. Moreover, peer deviance and parent-child relationship problems accounted for approximately 77% of the variance in early substance use. Findings also indicated that peer deviance, but not parent-child relationship problems, accounted uniquely for variance in early substance use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structural and Thermodynamic Variation in Nickel Aluminate Spinel

New structural and calorimetric data for samples of NiAl₂O₄ quenched from 600° to 1560°C are presented The spinel remains stoichiometric for all heat treatments. Based on the refinement of X-ray powder patterns, it is shown that the degree of disorder, defined as the mole fraction of tetrahedral sites occupied by Al³⁺, changes from x = 0.82 at 600°C to 0.78 at 1560°C. Simultaneously, the lattice parameter and enthalpy vary in a complex manner with quench temperature. The largest lattice parameter (0.80500 ± 0.00004 nm) and most exothermic enthalpy of annealing (heat released when sample is equilibrated at 780°C; -10.1 kJ/mol) occur for the sample quenched from 1100°C. A linear correlation exists between the heat of annealing and the lattice parameter. The results have been interpreted as a superposition of at least two effects: (1) the disordering of Ni²⁺ and Al³⁺ ions between octahedral (16d) and tetrahedral (8a) sites and (2) a second process, which may be a small amount of the disordering of ions into the usually empty (16c) sites.     

Etiological Contributions to Heavy Drinking From Late Adolescence to Young Adulthood.

The authors examined genetic and environmental contributions to stability and change in heavy drinking from late adolescence to young adulthood in a sample of 1,152 twin pairs. In men, heavy drinking was similarly heritable at ages 17 (h2 = .57) and 20 (h2 = .39), and its stability owed primarily to common genetic factors. In women, heavy drinking was less heritable than in men at ages 17 (h2 = .18) and 20 (h2 = .30) and its stability was primarily due to enduring shared environmental influences. P3 amplitude, an event-related brain potential marker of alcoholism risk, was less predictive of heavy drinking in women than in men, providing further support for the proposition that biological factors have less impact on heavy drinking in young adult women than in young adult men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A New Application of Solvent Extraction to Separate Copper from Extreme Acid Mine Drainage Producing Solutions for Electrochemical and Biological Recovery Processes

Over the last decade, AMD waters have gained more attention as a potential source of metals due to the emerging need to recover or recycle metals from secondary resources. Metals recovery supports sustainability and the development of a circular economy with benefits for resource conservation and the environment. In this study, five extractants (Acorga M5640, LIX 54, LIX 622, LIX 622 N, and LIX 864) diluted (15% (v/v)) in Shell GTL with 2.5% (v/v) octanol were compared and evaluated for Cu recovery from an extreme AMD sample (5.3?±?0.3 g/L Cu) collected at the inactive São Domingos Mine in the Iberian Pyrite Belt of Portugal. Of the five extractants, Acorga M5640 showed the best selective efficiency. Further tests showed that 30% (v/v) of this extractant was able to selectively extract ≈ 96.0% of the Cu from the AMD in one extraction step and all of the remaining Cu (to below detection) in three steps. Among the different stripping agents tested, 2 M sulfuric acid was the most efficient, with ≈ 99% of the Cu stripped, and the recyclability of the organic phase was confirmed in five successive cycles of extraction and stripping. Furthermore, contact time tests revealed that the extraction kinetics allows the transfer of ≈ 97% of the Cu in 15 min, and aqueous to organic phase ratios tests demonstrated a maximum loading capacity of ≈ 16 g/L Cu in the organic phase. Raising the concentration of Cu in the stripping solution (2 M sulfuric acid) to ≈ 46 g/L through successive striping steps showed the potential to recover elemental Cu using traditional electrowinning. Finally, a biological approach for Cu recovery from the stripping solution was evaluated by adding the supernatant of a sulfate-reducing bacteria culture to make different molar ratios of biogenic sulfide to copper; ratios over 1.75 resulted in precipitation of more than 95% of the Cu as covellite nanoparticles.

Graphical Abstract

     

Nanoscale assembly in biological systems: from neuronal cytoskeletal proteins to curvature stabilizing lipids

The review will describe experiments inspired by the rich variety of bundles and networks of interacting microtubules (MT), neurofilaments, and filamentous-actin in neurons where the nature of the interactions, structures, and structure-function correlations remain poorly understood. We describe how three-dimensional (3D) MT bundles and 2D MT bundles may assemble, in cell free systems in the presence of counter-ions, revealing structures not predicted by polyelectrolyte theories. Interestingly, experiments reveal that the neuronal protein tau, an abundant MT-associated-protein in axons, modulates the MT diameter providing insight for the control of geometric parameters in bio- nanotechnology. In another set of experiments we describe lipid-protein-nanotubes, and lipid nano-tubes and rods, resulting from membrane shape evolution processes involving protein templates and curvature stabilizing lipids. Similar membrane shape changes, occurring in cells for the purpose of specific functions, are induced by interactions between membranes and proteins. The biological materials systems described have applications in bio-nanotechnology.     

Interactive priming of biochar and labile organic matter mineralization in a smectite-rich soil

Biochar is considered as an attractive tool for long-term carbon (C) storage in soil. However, there is limited knowledge about the effect of labile organic matter (LOM) on biochar-C mineralization in soil or the vice versa. An incubation experiment (20 °C) was conducted for 120 days to quantify the interactive priming effects of biochar-C and LOM-C mineralization in a smectitic clayey soil. Sugar cane residue (source of LOM) at a rate of 0, 1, 2, and 4% (w/w) in combination with two wood biochars (450 and 550 °C) at a rate of 2% (w/w) were applied to the soil. The use of biochars (~ -36‰) and LOM (-12.7‰) or soil (-14.3‰) with isotopically distinct δ(13)C values allowed the quantification of C mineralized from biochar and LOM/soil. A small fraction (0.4-1.1%) of the applied biochar-C was mineralized, and the mineralization of biochar-C increased significantly with increasing application rates of LOM, especially during the early stages of incubation. Concurrently, biochar application reduced the mineralization of LOM-C, and the magnitude of this effect increased with increasing rate of LOM addition. Over time, the interactive priming of biochar-C and LOM-C mineralization was stabilized. Biochar application possesses a considerable merit for long-term soil C-sequestration, and it has a stabilizing effect on LOM in soil.     

Quantifying remediation effectiveness under variable external forcing using contaminant rating curves

Remediation efforts are typically assessed through before-and-after comparisons of contaminant concentrations or loads. These comparisons can be misleading when external drivers, such as weather conditions, differ between the pre- and postremediation monitoring periods. Here, we show that remediation effectiveness may be better assessed by comparing pre- and postremediation contaminant rating curves, which permit "all else equal" comparisons of pre- and postremediation contaminant concentrations and loads under at any specified external forcing. We illustrate this approach with a remediation case study at an abandoned mercury mine in Northern California. Measured mercury loads in the stream draining the mine site were a factor of 1000 smaller after the remediation than before, superficially suggesting that the cleanup was 99.9% effective, but rainstorms were weaker and less frequent during the postremediation monitoring period. Our analysis shows that this difference in weather conditions alone reduced mercury loads at our site by a factor of 73-85, with a further factor of 12.6-14.5 being attributable to the remediation itself, implying that the cleanup was 92-93% (rather than 99.9%) effective. Our results illustrate the need to account for external confounding drivers when assessing remediation efforts, particularly in systems with highly episodic forcing.