Reevaluating the ability of cerebellum in associative motor learning.

It has been well established that the cerebellum and its associated circuitry constitute the essential neuronal system for both delay and trace classical eyeblink conditioning (DEC and TEC). However, whether the cerebellum is sufficient to independently modulate the DEC, and TEC with a shorter trace interval remained controversial. Here, we used direct optogenetic stimulation of mossy fibers in the middle cerebellar peduncle (MCP) as a conditioned stimulus (CS) replacement for the peripheral CS (eg, a tone CS or a light CS) paired with a periorbital shock unconditioned stimulus (US) to examine the ability of the cerebellum to learn the DEC and the TEC with various trace intervals. Moreover, neural inputs to the pontine nucleus (PN) were pharmacological blocked to limit the associative motor learning inside the cerebellum. We show that all rats quickly acquired the DEC, indicating that direct optogenetic stimulation of mossy fibers in the left MCP is a very effective and sufficient CS to establish DEC and to limit the motor learning process inside the cerebellum. However, only five out of seven rats acquired the TEC with a 150-ms trace interval, three out of nine rats acquired the TEC with a 350-ms trace interval, and none of the rats acquired the TEC with a 500-ms trace interval. Moreover, pharmacological blocking glutamatergic and GABAergic inputs to the PN from the extra-cerebellar and cerebellar regions has no significant effect on the DEC and TEC learning with the optogenetic CS. These results indicate that the cerebellum has the ability to independently support both the simple DEC, and the TEC with a trace interval of 150 or 350 ms, but not the TEC with a trace interval of 500 ms. The present results are of great importance in our understanding of the mechanisms and ability of the cerebellum in associative motor learning and memory.

Direct observation of localized surface plasmon field enhancement by Kelvin probe force microscopy.

A surface plasmon (SP) is a fundamental excitation state that exists in metal nanostructures. Over the past several years, the performance of optoelectronic devices has been improved greatly via the SP enhancement effect. In our previous work, the responsivity of GaN ultraviolet detectors was increased by over 30 times when using Ag nanoparticles. However, the physics of the SP enhancement effect has not been established definitely because of the lack of experimental evidence. To reveal the physical origin of this enhancement, Kelvin probe force microscopy (KPFM) was used to observe the SP-induced surface potential reduction in the vicinity of Ag nanoparticles on a GaN epilayer. Under ultraviolet illumination, the localized field enhancement induced by the SP forces the photogenerated electrons to drift close to the Ag nanoparticles, leading to a reduction of the surface potential around the Ag nanoparticles on the GaN epilayer. For an isolated Ag nanoparticle with a diameter of ~200 nm, the distribution of the SP localized field is located within 60 nm of the boundary of the Ag nanoparticle. For a dimer of Ag nanoparticles, the localized field enhancement between the nanoparticles was the strongest. The results presented here provide direct experimental proof of the localized field enhancement. These results not only explain the high performance of GaN detectors observed with the use of Ag nanoparticles but also reveal the physical mechanism of SP enhancement in optoelectronic devices, which will help us further understand and improve the performance of SP-based optoelectronic devices in the future.

Comparison of the efficacy and safety of intensive-dose and standard-dose statin treatment for stroke prevention: A meta-analysis.

BACKGROUND: Previous study indicated that high-dose statin treatment might increase the risk of hemorrhagic stroke and adverse reactions. We aim to compare the efficacy and safety of intensive-dose and standard-dose statin treatment for preventing stroke in high-risk patients. METHODS: A thorough search was performed of multiple databases for publications from 1990 to June 2015. We selected the randomized clinical trials comparing standard-dose statin with placebo and intensive-dose statin with standard-dose statin or placebo for the prevention of stroke events in patients. Duplicate independent data extraction and bias assessments were performed. Data were pooled using a fixed-effects model or a random-effects model if significant heterogeneity was present. RESULTS: For the all stroke incidences, intensive-dose statin treatment compared with placebo treatment and standard-dose statin treatment compared with placebo treatment showed a significant 21% reduction in relative risk (RR) (RR 0.79, 95% confidence interval (CI) [0.71, 0.87], P < 0.00001) and an 18% reduction in RR (RR 0.82, 95% CI [0.73, 0.93], P = 0.002) in the subgroup without renal transplant recipients and patients undergoing regular hemodialysis separately. For the fatal stroke incidences, intensive-dose statin treatment compared with standard dose or placebo was effective reducing fatal stroke (RR 0.61, 95% CI [0.39, 0.96], P = 0.03) and the RR was 1.01 (95% CI [0.85, 1.20], P = 0.90) in standard-dose statin treatment compared with placebo. CONCLUSION: The results of this meta-analysis suggest that intensive-dose statin treatment might be more favorable for reducing the incidences of all strokes than standard-dose statin treatment, especially for patients older than 65 years in reducing the incidences of all stroke incidences.

Plasma-induced, nitrogen-doped graphene-based aerogels for high-performance supercapacitors.

Commonly used energy storage devices include stacked layers of active materials on two-dimensional sheets, and the limited specific surface area restricts the further development of energy storage. Three-dimensional (3D) structures with high specific surface areas would improve device performance. Herein, we present a novel procedure to fabricate macroscopic, high-quality, nitrogen-doped, 3D graphene/nanoparticle aerogels. The procedure includes vacuum filtration, freeze-drying, and plasma treatment, which can be further expanded for large-scale production of nitrogen-doped, graphene-based aerogels. The behavior of the supercapacitor is investigated using a typical nitrogen-doped graphene/Fe3O4 nanoparticle 3D structure (NG/Fe3O4). Compared with 3D graphene/Fe3O4 structures prepared by the traditional hydrothermal method, the NG/Fe3O4 supercapacitor prepared by the present method has a 153% improvement in specific capacitance, and there is no obvious decrease in specific capacitance after 1000 cycles. The present work provides a new and facile method to produce large-scale, 3D, graphene-based materials with high specific capacitance for energy storage.

Targeted migration and differentiation of engrafted neural precursor cells in amyloid beta-treated hippocampus in rats.

OBJECTIVE: To observe the migration and differentiation of the neural precursor cells (NPCs) that derived from murine embryonic stem cells (ESCs) when they were transplanted into amyloid beta (A beta)-treated rat hippocampus. METHODS: MESPU35, a murine ESC cell line that express the enhanced green fluorescent protein (EGFP), was induced differentiation into nestin-positive NPCs by modified serum-free methods. The A beta plaques and the differentiation of the grafted cells were observed by immunofluorescent staining. RESULTS: Comparing 16 weeks with 4 weeks post-transplantation, the migration distance increased about 5 times; the rate of migratory NPCs differentiating into glial fibrillary acidic protein (GFAP)-positive cells kept rising from (30.41+/-1.45) % to (49.25+/-1.23) %, and the rate of NPCs differentiating into neurofilament 200 (NF200) positive cells increased from (16.68+/-0.95) % to (27.94+/-1.21) %. Meanwhile, the GFAP-positive cells targeting to the ipsilateral side of A beta plaques increased from 60.2% to 81.3%, while the NF200-positive cells increased from 61.3% to 84.1%. The migration distance had significant positive linear correlations to the neuronal differentiation rate (r = 0.991) and to the astrocytic differentiation rate (r = 0.953). CONCLUSION: Engrafted NPCs migrate targetedly to the A beta injection site and differentiate into neurons and astrocytes.

Comparative study of histopathology changes between the PS1/APP double transgenic mouse model and Abeta1-40 -injected rat model of Alzheimer disease.

Objective To identify the genetype of the PS1/APP double transgenic mouse model, then to analyse the histopathological changes in the brain and compare the differences between the transgenic mice models and Abeta1-40-injected rats models of Alzheimer disease. Methods The modified congo red staining, Nissl's staining and immunohistology staimouse extensively displayed Abeta deposits, activation of astrocyte respectively. Results (1) The PS1/APP transgenic mouse extensively displayed Abeta deposits in the cortex and hippocampal structures, and GFAP positive cells were aggregated in mass and surrounded the congo red-positive plaque. (2) The Abeta1-40-intrahippocampal-injected rat model showed the Abeta plaque deposits in the dentate gyrus of the hippocampus, with the astrocyte surrounded. The neurons loss was significant in the injection point and pin hole of injection with Nissl's staining methods. GFAP-positive cells increased significantly compared with the uninjected lateral of the hippocampus. Conclusion Although Abeta1-40-injected rat models could simulate some characteristic pathological features of human Alzheimer diseases, Abeta deposits and neurons loss in partial hippocampal, it would not simulate the progressive degenenration in the brain of AD. The double transgenic PS1/APP mice could simulate the specific pathogenesis and progressive changes of AD, mainly is Abeta deposits and the spongiocyte response, while no neurons loss were observed in this model.