141 research outputs found
The Effects of Video Games on Human Intelligence
With the help of rapidly growing electronics industry offering more affordable electronic gaming devices, an increasing number of people have stepped into the realm of video games and as a result, playing video games has become part of life for many to some extent. While the majority of people are embracing the fun and the thrill that video games have brought about, a handful of people are still holding relatively negative opinions on video games, thinking that playing video game is just a waste of time and money. In fact, the truth is quite the opposite. It has proved that video game is actually playing a multifaceted positive role in improving people’s intelligence, or making people smarter on the physiological aspect, the psychological aspect as well as the sociological aspect
Characterization of PPAR-gamma 1 and PPAR-gamma 2 in Knockin and Knockout Mouse Models
The global epidemic of obesity and type II diabetes has led to a growing interest in the underlying mechanisms of metabolic diseases. The peroxisome proliferator-activated receptor gamma (PPARγ) is a member of the nuclear receptor superfamily, and is vital for the transcriptional regulation of adipogenesis, insulin sensitivity and lipid metabolism. In the mouse model, it has been demonstrated that global knockout of PPARγ leads to severe metabolic disturbance, resulting in embryonic lethality. However, the specific regulatory roles of its two protein isoforms, PPARγ1 and PPARγ2, remain uncertain, due to limitations of reagents and appropriate mouse models. To investigate the hypothesis that PPARγ1 and PPARγ2 are functionally distinct, we generated PPARγ1 and PPARγ2 tagged mice using CRISPR-Cas9 technology. PPARγ1 and PPARγ2 specific knockout mice were also generated incidentally during this process, via aberrant recombination. By reverse-transcription quantitative PCR (RT-qPCR), and western blot, we confirmed the presence of the appropriate tags in our PPARγ1 and PPARγ2 tagged mice, with no significant disruption to mRNA or protein expression. Furthermore, we found that PPARγ1 mRNA and protein expression levels were reduced in our PPARγ1 knockout model, compared to the wild type. Interestingly, we found that there was a complete loss of PPARγ2 protein expression, despite an increase in PPARγ2 mRNA expression in our PPARγ2 knockout model. These data suggest that we have successfully generated PPARγ1 and PPARγ2 knockin and knockout mice. Our mouse models provide a valuable tool to study the individual roles of PPARγ1 and PPARγ2 in adipogenesis, insulin sensitivity and metabolic disease
Learning to Accelerate Symbolic Execution via Code Transformation
Symbolic execution is an effective but expensive technique for automated test generation. Over the years, a large number of refined symbolic execution techniques have been proposed to improve its efficiency. However, the symbolic execution efficiency problem remains, and largely limits the application of symbolic execution in practice. Orthogonal to refined symbolic execution, in this paper we propose to accelerate symbolic execution through semantic-preserving code transformation on the target programs. During the initial stage of this direction, we adopt a particular code transformation, compiler optimization, which is initially proposed to accelerate program concrete execution by transforming the source program into another semantic-preserving target program with increased efficiency (e.g., faster or smaller). However, compiler optimizations are mostly designed to accelerate program concrete execution rather than symbolic execution. Recent work also reported that unified settings on compiler optimizations that can accelerate symbolic execution for any program do not exist at all. Therefore, in this work we propose a machine-learning based approach to tuning compiler optimizations to accelerate symbolic execution, whose results may also aid further design of specific code transformations for symbolic execution. In particular, the proposed approach LEO separates source-code functions and libraries through our program-splitter, and predicts individual compiler optimization (i.e., whether a type of code transformation is chosen) separately through analyzing the performance of existing symbolic execution. Finally, LEO applies symbolic execution on the code transformed by compiler optimization (through our local-optimizer). We conduct an empirical study on GNU Coreutils programs using the KLEE symbolic execution engine. The results show that LEO significantly accelerates symbolic execution, outperforming the default KLEE configurations (i.e., turning on/off all compiler optimizations) in various settings, e.g., with the default training/testing time, LEO achieves the highest line coverage in 50/68 programs, and its average improvement rate on all programs is 46.48%/88.92% in terms of line coverage compared with turning on/off all compiler optimizations
FGF Receptor-Mediated Gene Delivery Using Ligands Coupled to PEI-β-CyD
A novel vector with high gene delivery efficiency and special cell-targeting ability was developed using a good strategy that utilized low-molecular-weight polyethylenimine (PEI; molecular weight: 600 KDa [PEI600]) crosslinked to β-cyclodextrin (β-CyD) via a facile synthetic route. Fibroblast growth factor receptors (FGFRs) are highly expressed in a variety of human cancer cells and are potential targets for cancer therapy. In this paper, CY11 peptides, which have been proven to combine especially with FGFRs on cell membranes were coupled to PEI-β-CyD using N-succinimidyl-3-(2-pyridyldithio) propionate as a linker. The ratios of PEI600, β-CyD, and peptide were calculated based on proton integral values obtained from the 1H-NMR spectra of the resulting products. Electron microscope observations showed that CY11-PEI-β-CyD can efficiently condense plasmid DNA (pDNA) into nanoparticles of about 200 nm, and MTT assays suggested the decreased toxicity of the polymer. Experiments on gene delivery efficiency in vitro showed that CY11-PEI-β-CyD/pDNA polyplexes had significantly greater transgene activities than PEI-β-CyD/pDNA in the COS-7 and HepG2 cells, which positively expressed FGFR, whereas no such effect was observed in the PC-3 cells, which negatively expressed FGFR. Our current research indicated that the synthesized nonviral vector shows improved gene delivery efficiency and targeting specificity in FGFR-positive cells
Direct conversion of astrocytes into neuronal cells by drug cocktail
Direct conversion of astrocytes into neuronal cells by
drug cocktail
Cell Research advance online publication 2 October 2015; doi:10.1038/cr.2015.120
Dear Editor,
Neurological disorder is one of the greatest threats
to public health according to the World Health Organization.
Because neurons have little or no regenerative
capacity, conventional therapies for neurological disorders
yielded poor outcomes. While the introduction of
exogenous neural stem cells or neurons holds promise,
many challenges still need to be tackled, including cell
resource, delivery strategy, cell integration and cell
maturation. Reprogramming of fibroblasts into induced
pluripotent stem cells or directly into desirable neuronal
cells by transcription factors (TFs) or small molecules
can solve some problems, but other issues remain to be
addressed, including safety, conversion efficiency and
epigenetic memory [1, 2].
Astrocytes are considered to be the ideal starting
candidate cell type for generating new neurons, due to
their proximity in lineage distance to neurons and ability
to proliferate after brain damage. Many studies have
already revealed that astrocytes of the central nervous
system can be reprogrammed into induced neuronal cells
by virus-mediated overexpression of specific TFs in vitro
and in vivo [3-6]. However, application of this virus-mediated
direct conversion is still limited due to concerns
on clinical safety. We have previously reported direct
conversion of somatic cells into neural progenitor cells
(NPCs) in vitro by cocktail of small molecules under hypoxia
[7]. Here we set out to explore whether astrocytes
can be induced into neuronal cells by the chemical cocktail
in vitro
Downregulation of hypoxia-inducible factor-1α by RNA interference alleviates the development of collagen-induced arthritis in rats
Rheumatoid arthritis (RA) is the most common type of autoimmune arthritis. Hypoxia-inducible factor-1α (HIF-1α) as a transcription factor in response to hypoxia suggests that it could be a potential therapeutic target for the treatment of RA. In this study, we assessed whether the HIF pathway blockade attenuates the manifestations of RA in the collagen-induced arthritis (CIA) rat model. We constructed a short hairpin RNA (shRNA) lentiviral expression vector targeting HIF-1α (pLVX-shRNA-HIF-1α) and to achieve HIF-1α RNA interference. Quantitative RT-PCR, immunofluorescence staining, and western blot were used to detect the expressions of HIF-1α, vascular endothelial growth factor (VEGF), phsopho (p)-p65, and p-IКBɑ mRNA and protein, respectively. Micro-computed tomography was used to investigate joint morphology at different time points after CIA induction. Moreover, enzyme-linked immunosorbent assay (ELISA) was used to monitor the expression of inflammatory cytokines. In vitro analyses revealed that pLVX-shRNA-HIF-1α effectively inhibited the expression of HIF-1α and VEGF and led to the activation of p-65 and p-IКBɑ, as well as decreased proinflammatory cytokine expression in cell culture. Inhibition of HIF-1α in rats decreased signs of a systemic inflammatory condition, together with decreased pathological changes of RA. Moreover, downregulation of HIF-1α expression markedly reduced the synovitis and angiogenesis. In conclusion, we have shown that pharmacological inhibition of HIF-1 may improve the clinical manifestations of RA
Large-scale patterned quantum dots as color conversion layer for organic light emitting diode by inkjet printing
In this work, we fabricated 6.6-inch QD display panel by inkjet printing technology, being cooperated with active matrix organic light emitting diodes (AMOLEDs). Here 3-stack blue OLEDs (BOLEDs) with top-emission structure acted as backlight and red QD layer acted as converted materials, which exhibited high quantum efficiency, high luminance, high color purity and improved wide viewing angle of output emission. We believe that inkjet-printed QD display with AMOLEDs would be promising candidate for the next generation display and lighting in the near future
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