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Abstract: In this study, LaB6 nanoparticles are used as a novel nanomaterial for near-infrared (NIR) photothermal therapy because they are cheaper than nanostructured gold, are easy to prepare and have an excellent NIR photothermal conversion property. Furthermore, the surface of LaB6 nanoparticles is coated with a carbon-doped silica (C-SiO2) shell to introduce a fluorescent property and improve stability and biocompatibility. The resulting LaB6@C-SiO2 nanoparticles retain the excellent NIR photothermal conversion property and exhibit a bright blue emission under UV irradiation or a green emission under visible irradiation. Using a HeLa cancer cell line, it is demonstrated that LaB6@C-SiO2 nanoparticles have no significant cytotoxicity, but their presence leads to remarkable cell death after NIR irradiation. In addition, from the observation of cellular uptake, the fluorescence labeling function of LaB6@SiO2 (LaB6 core/SiO2 shell) nanoparticles is also confirmed. These results suggest that LaB6@C-SiO2 nanoparticles may potentially serve as an efficient multifunctional nano-platform for simultaneous fluorescent imaging and NIR-triggered photothermal therapy of cancer cells. [Copyright &y& Elsevier]

Near saturation, air bubbles and pockets can be trapped in the porous network of soils. The aim of this paper was to present a coupled model that takes into account the effect of this entrapped air on the poro-elasto-plastic behavior of the soil. The model takes into account the physical-mechanical interactions between different phases as well as the kinematics of each constituent (liquid water, dissolved air, gaseous air and solid grains). This new model was implemented in a FEM code. Some numerical simulations were performed to demonstrate its ability to reproduce a continuous transition of unsaturated to saturated states. [ABSTRACT FROM AUTHOR]

Abstract: There is increasing evidence indicating that estrogen replacement therapy produces neuroprotective actions but has undesirable side effects on the reproductive system. Raloxifene is a selective estrogen receptor modulator that exerts estrogen agonist action in the brain while acting as an estrogen antagonist in the reproductive system. In the present study, we investigated whether raloxifene affected the glutamate-induced calcium (Ca2+) overload in rat cultured cortical neurons. The bulk cytosolic intracellular Ca2+ level was measured by using confocal microscopy with fluorescent Ca2+ probe fluo3. Whole-cell recording technique was used to observe the effects of raloxifene on N-methyl-d-aspartate (NMDA)-evoked and voltage-activated Ca2+ currents in cultured cortical neurons. Pre-exposure of cortical neurons to raloxifene (0.5μM–10μM) for 3 min attenuated intracellular Ca2+ increase induced by application of glutamate (300μM) for 1 min. The action of raloxifene was reversible after washout. ICI 182,780 and thapsigargin did not block the action of raloxifene. In whole-cell recording experiments, raloxifene (10μM) significantly reduced the amplitude of the high-voltage-activated Ca2+ current but had no effect on NMDA-evoked Ca2+ current. The present study demonstrates that raloxifene acutely reduces glutamate-induced intracellular Ca2+ increase probably via inhibition of high-voltage-activated calcium channels. [Copyright &y& Elsevier]

Opioid-induced rewarding and motorstimulant effects are mediated by an increased activity of the ventral tegmental area (VTA) dopamine (DA) neurons. The excitatory mechanism of opioids on VTA-DA neurons has been proposed to be due to the depression of GABAergic synaptic transmission in VTA-DA neurons. However, how opioids depress GABAergic synaptic transmission in VTA-DA neurons remain to be studied. In the present study, we explored the mechanism of the inhibitory effect of [D-Ala 2 , N-Me-Phe 4 , Gly 5 -ol]-enkephalin (DAMGO) on GABAergic synaptic transmission in VTA-DA neurons using multiple approaches and techniques. Our results showed that (1) DAMGO inhibits GABAergic inputs in VTA-DA neurons at presynaptic sites; (2) effect of DAMGO on GABAergic inputs in VTA-DA neurons is inhibited by potassium channel blocker 4-aminopyridine (4-AP) and G i protein inhibitor N -ethylmaleimide (NEM); (3) phospholipase A 2 (PLA 2 ) does not mediate the effect of DAMGO on GABAergic inputs in VTA-DA neurons, but mediates it in the periaqueductal gray (PAG); (4) multiple downstream signaling molecules of μ receptors do not mediate the effect of DAMGO on GABAergic inputs in VTA-DA neurons. These results suggest that DAMGO depresses inhibitory synaptic transmission via μ receptor-G i protein-K v channel pathway in VTA-DA neurons, but via μ receptor-PLA 2 pathway in PAG neurons. [ABSTRACT FROM AUTHOR]

Abstract: Various studies have shown that increased activity of the hypothalamic–pituitary–adrenal (HPA) axis can predict the onset of adolescent depressive symptomatology. We have previously shown that adolescents making the transition to high school present a significant increase in cortisol levels, the main product of HPA axis activation. In the present study, we evaluated whether a school-based education program developed according to the current state of knowledge on stress in psychoneuroendocrinology decreases cortisol levels and/or depressive symptoms in adolescents making the transition to high school. Participants were 504 Year 7 high school students from two private schools in the Montreal area. Adolescents of one school were exposed to the DeStress for Success Program while adolescents from the other school served as controls. Salivary cortisol levels and depressive symptomatology were measured before, immediately after as well as 3months after exposure to the program. Measures of negative mood were obtained at baseline in order to determine whether adolescents starting high school with specific negative moods were differentially responsive to the program. The results show that only adolescents starting high school with high levels of anger responded to the intervention with a significant decrease in cortisol levels. Moreover, we found that adolescents who took part in the intervention and showed decreasing cortisol levels following the intervention (responders) were 2.45 times less at risk to suffer from clinical and subclinical depressive states three months post-intervention in comparison to adolescents who showed increasing cortisol levels following the intervention (nonresponders). This study provides the first evidence that a school-based program on stress is effective at decreasing cortisol levels and depressive symptomatology in adolescents making the transition to high school and it helps explain which adolescents are sensitive to the program and what are some of the characteristics of these individuals. [Copyright &y& Elsevier]

Abstract: Heroin is reported to cause spongiform leukoencephalopathy (SLE) in heroin addicts and the exact mechanism has not yet been identified. In the present study, we found that heroin could induce apoptosis of primary cultured cerebellar granule cells (CGCs) and Bim was upregulated both transcriptionally and post transcriptionally during CGCs apoptosis. Upregulated Bim translocated to mitochondria and Bax was activated under heroin treatment. Genetic knockdown of Bim using lentiviruses significantly prevented neuronal apoptosis induced by heroin. Meanwhile, c-Jun N-terminal kinase (JNK)/c-Jun pathway was activated in heroin-induced apoptosis. Bim was demonstrated as a downstream target of JNK/c-Jun pathway in this process because pharmacological inhibition of JNK reduced the levels of Bim mRNA and protein. These results indicate that Bim plays a critical role in the neurotoxic process by heroin and JNK/c-Jun pathway acts upstream of Bim in regulating heroin-induced neuronal death. This represents a detailed mechanism of heroin-induced neuronal apoptosis and may provide a new and effective strategy to treat heroin-induced addiction and SLE. [Copyright &y& Elsevier]

Abstract: Formation mechanisms of precipitates containing multiple-metal species in silicon are elucidated by nano-scale morphology and phase investigations performed by synchrotron-based X-ray microprobe techniques. Precipitates formed at low (655°C) and high (1200°C+) temperatures exhibit distinguishing features indicative of unique formation mechanisms. After lower-temperature annealing, co-localized single-metal silicide phases are observed, consistent with classical models predicting that dissolved, supersaturated metal atoms will precipitate into solid second-phase particles. Precise precipitate morphologies are found to depend on the local crystallographic environment. In precipitates formed during slow cooling from higher-temperature anneals, nano-scale phase separation and intermetallic phases are evident, suggestive of a high-temperature transition through a liquid phase. Based on experimental results and phase diagram information, it is proposed that under certain conditions, liquid metal–silicon droplets may form within the silicon matrix, possibly with the potential to getter additional metal atoms via liquid–solid segregation. [Copyright &y& Elsevier]

Current knowledge of fine-particle airborne pollution concentrations and constituents with diameters below 2.5 μm (PM2.5) is limited. Sources are both natural and man-made. Here we describe two types of experiments performed using the advanced photon source facility at Chicago, and compare the results with PIXE analysis on the same fine particle filters. These are firstly broad beam (2 mm) studies with tuned synchrotron beam energies to help resolve over-lapping X-rays, and secondly highly focused X-ray beam studies (0.2 μm) of individual fine particles from airborne pollution combustion sources. [Copyright &y& Elsevier]