Exposure to mercury ions can damage the human brain, the nervous system, the endocrine system, and other biological systems. Much effort has therefore been made to develop real-time monitoring of mercury variations, and many mercury-ion sensors have been reported recently. In this review, mercury-ion sensors reported since 2008 are described and discussed. The sensors are classified as molecular, nanomaterial based, and others. Molecular sensors are based on chemical and hydrogen bond formation, and the other types are based on changes in the materials used.

Aggregation of the full‐length amyloid‐β (Aβ) and β2‐microglobulin (β2m) proteins is associated with Alzheimer's disease and dialysis‐related amyloidosis, respectively. This assembly process is not restricted to full‐length proteins, however, many short peptides also assemble into amyloid fibrils in vitro. Remarkably, the kinetics of amyloid‐fibril formation of all these molecules is generally described by a nucleation‐polymerization process characterized by a lag phase associated with the formation of a nucleus, after which fibril elongation occurs rapidly. In this study, we report using long molecular dynamics simulations with the OPEP coarse‐grained force field, the thermodynamics and dynamics of the octamerization for two amyloid 7‐residue peptides: the β2m83‐89 NHVTLSQ and Aβ16‐22 KLVFFAE fragments. Based on multiple trajectories run at 310 K, totaling 2.2 μs (β2m83‐89) and 4.8 μs (Aβ16‐22) and starting from random configurations and orientations of the chains, we find that the two peptides not only share common but also very different aggregation properties. Notably, an increase in the hydrophobic character of the peptide, as observed in Aβ16‐22 with respect to β2m83‐89 impacts the thermodynamics by reducing the population of bilayer β‐sheet assemblies. Higher hydrophobicity is also found to slow down the dynamics of β‐sheet formation by enhancing the averaged lifetime of all configuration types (CT) and by reducing the complexity of the CT transition probability matrix. Proteins 2009. © 2008 Wiley‐Liss, Inc.

We report the designed synthesis of Co 1,3,5-benzenetricarboxylate coordination polymers (CPs) via a straightforward hydrothermal method, in which three kinds of reaction solvents are selected to form CPs with various morphologies and dimensions. When tested as anode materials in Li-ion battery, the cycling stabilities of the three CoBTC CPs at a current density of 100 mA g(-1) have not evident difference; however, the reversible capacities are widely divergent when the current density is increased to 2 A g(-1). The optimized product CoBTC-EtOH maintains a reversible capacity of 473 mAh g(-1) at a rate of 2 A g(-1) after 500 galvanostatic charging/discharging cycles while retaining a nearly 100% Coulombic efficiency. The hollow microspherical morphology, accessible specific area, and the absence of coordination solvent of CoBTC-EtOH might be responsible for such difference. Furthermore, the ex situ soft X-ray absorption spectroscopy studies of CoBTC-EtOH under different states-of-charge suggest that the Co ions remain in the Co(2+) state during the charging/discharging process. Therefore, Li ions are inserted to the organic moiety (including the carboxylate groups and the benzene ring) of CoBTC without the direct engagement of Co ions during electrochemical cycling.

Dietary restriction (DR; reduced calorie intake) increases the lifespan of rodents and increases their resistance to cancer, diabetes and other age-related diseases. DR also exerts beneficial effects on the brain including enhanced learning and memory and increased resistance of neurons to excitotoxic, oxidative and metabolic insults. The mechanisms underlying the effects of DR on neuronal plasticity and survival are unknown. In the present study we show that levels of brain-derived neurotrophic factor (BDNF) are significantly increased in the hippocampus, cerebral cortex and striatum of mice maintained on an alternate day feeding DR regimen compared to animals fed ad libitum. Damage to hippocampal neurons induced by the excitotoxin kainic acid was significantly reduced in mice maintained on DR, and this neuroprotective effect was attenuated by intraventricular administration of a BDNF-blocking antibody. Our findings show that simply reducing food intake results in increased levels of BDNF in brain cells, and suggest that the resulting activation of BDNF signaling pathways plays a key role in the neuroprotective effect of DR. These results bolster accumulating evidence that DR may be an effective approach for increasing the resistance of the brain to damage and enhancing brain neuronal plasticity.

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