156 research outputs found

    Fractal Fluctuations and Quantum-Like Chaos in the Brain by Analysis of Variability of Brain Waves: A New Method Based on a Fractal Variance Function and Random Matrix Theory

    Full text link
    We developed a new method for analysis of fundamental brain waves as recorded by EEG. To this purpose we introduce a Fractal Variance Function that is based on the calculation of the variogram. The method is completed by using Random Matrix Theory. Some examples are given

    Optical Control of Mammalian Endogenous Transcription and Epigenetic States

    Get PDF
    The dynamic nature of gene expression enables cellular programming, homeostasis, and environmental adaptation in living systems. Dissection of causal gene functions in cellular and organismal processes therefore necessitates approaches that enable spatially and temporally precise modulation of gene expression. Recently, a variety of microbial and plant-derived light-sensitive proteins have been engineered as optogenetic actuators, enabling high precision spatiotemporal control of many cellular functions1-11. However, versatile and robust technologies that enable optical modulation of transcription in the mammalian endogenous genome remain elusive. Here, we describe the development of Light-Inducible Transcriptional Effectors (LITEs), an optogenetic two-hybrid system integrating the customizable TALE DNA-binding domain12-14 with the light-sensitive cryptochrome 2 protein and its interacting partner CIB1 from Arabidopsis thaliana. LITEs do not require additional exogenous chemical co-factors, are easily customized to target many endogenous genomic loci, and can be activated within minutes with reversibility3,4,6,7,15. LITEs can be packaged into viral vectors and genetically targeted to probe specific cell populations. We have applied this system in primary mouse neurons, as well as in the brain of awake mice in vivo to mediate reversible modulation of mammalian endogenous gene expression as well as targeted epigenetic chromatin modifications. The LITE system establishes a novel mode of optogenetic control of endogenous cellular processes and enables direct testing of the causal roles of genetic and epigenetic regulation in normal biological processes and disease states

    Optical control of mammalian endogenous transcription and epigenetic states

    Get PDF
    A theoretical underpinning of the standard model of fundamental particles and interactions is CPT invariance, which requires that the laws of physics be invariant under the combined discrete operations of charge conjugation, parity and time reversal. Antimatter, the existence of which was predicted by Dirac, can be used to test the CPT theorem—experimental investigations involving comparisons of particles with antiparticles are numerous. Cold atoms and anti-atoms, such as hydrogen and antihydrogen, could form the basis of a new precise test, as CPT invariance implies that they must have the same spectrum. Observations of antihydrogen in small quantities and at high energies have been reported at the European Organization for Nuclear Research (CERN) and at Fermilab, but these experiments were not suited to precision comparison measurements. Here we demonstrate the production of antihydrogen atoms at very low energy by mixing trapped antiprotons and positrons in a cryogenic environment. The neutral anti-atoms have been detected directly when they escape the trap and annihilate, producing a characteristic signature in an imaging particle detector

    Interventions for the treatment of oral cavity and oropharyngeal cancer:chemotherapy

    Get PDF
    <b>Background:</b> Oral cavity and oropharyngeal cancers are frequently described as part of a group of oral cancers or head and neck cancer. Treatment of oral cavity cancer is generally surgery followed by radiotherapy, whereas oropharyngeal cancers, which are more likely to be advanced at the time of diagnosis, are managed with radiotherapy or chemoradiation. Surgery for oral cancers can be disfiguring and both surgery and radiotherapy have significant functional side effects, notably impaired ability to eat, drink and talk. The development of new chemotherapy agents, new combinations of agents and changes in the relative timing of surgery, radiotherapy, and chemotherapy treatments may potentially bring about increases in both survival and quality of life for this group of patients.<p></p> <b>Objectives:</b> To determine whether chemotherapy, in addition to radiotherapy and/or surgery for oral cavity and oropharyngeal cancer results in improved survival, disease free survival, progression free survival, locoregional control and reduced recurrence of disease. To determine which regimen and time of administration (induction, concomitant or adjuvant) is associated with better outcomes.<p></p> <b>Search strategy:</b> Electronic searches of the Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE, EMBASE, AMED were undertaken on 28th July 2010. Reference lists of recent reviews and included studies were also searched to identify further trials.<p></p> <b>Selection criteria:</b> Randomised controlled trials where more than 50% of participants had primary tumours in the oral cavity or oropharynx, and which compared the addition of chemotherapy to other treatments such as radiotherapy and/or surgery, or compared two or more chemotherapy regimens or modes of administration, were included.<p></p> <b>Data collection and analysis:</b> Trials which met the inclusion criteria were assessed for risk of bias using six domains: sequence generation, allocation concealment, blinding, completeness of outcome data, selective reporting and other possible sources of bias. Data were extracted using a specially designed form and entered into the characteristics of included studies table and the analysis sections of the review. The proportion of participants in each trial with oral cavity and oropharyngeal cancers are recorded in Additional Table 1.<p></p> <b>Main results:</b> There was no statistically significant improvement in overall survival associated with induction chemotherapy compared to locoregional treatment alone in 25 trials (hazard ratio (HR) of mortality 0.92, 95% confidence interval (CI) 0.84 to 1.00). Post-surgery adjuvant chemotherapy was associated with improved overall survival compared to surgery +/- radiotherapy alone in 10 trials (HR of mortality 0.88, 95% CI 0.79 to 0.99), and there was an additional benefit of adjuvant concomitant chemoradiotherapy compared to radiotherapy in 4 of these trials (HR of mortality 0.84, 95% CI 0.72 to 0.98). Concomitant chemoradiotherapy resulted in improved survival compared to radiotherapy alone in patients whose tumours were considered unresectable in 25 trials (HR of mortality 0.79, 95% CI 0.74 to 0.84). However, the additional toxicity attributable to chemotherapy in the combined regimens remains unquantified.<p></p> <b>Authors' conclusions:</b> Chemotherapy, in addition to radiotherapy and surgery, is associated with improved overall survival in patients with oral cavity and oropharyngeal cancers. Induction chemotherapy is associated with a 9% increase in survival and adjuvant concomitant chemoradiotherapy is associated with a 16% increase in overall survival following surgery. In patients with unresectable tumours, concomitant chemoradiotherapy showed a 22% benefit in overall survival compared with radiotherapy alone.<p></p&gt

    Modelling Greenland Ice Sheet inception and sustainability during the Late Pliocene

    Get PDF
    Understanding the evolution and dynamics of ice sheet growth during past warm periods is a very important topic considering the potential total removal of the Greenland ice sheet in the future. In this regard, one key event is the full glaciation of Greenland that occurred at the end of the Pliocene warm period, but remains partially unexplained. Previous modelling studies succeeded in reproducing this full glaciation either by imposing an unrealistically low CO2 value or by imposing a partial ice sheet over the surface of Greenland. Although highlighting some fundamental mechanisms, none of these studies are fully satisfactory because they do not reflect realistic conditions occurring during the Late Pliocene. Through a series of simulations with the coupled climate model IPSL-CM5A used to force the ice sheet model GRISLI, we show that a drop in CO2 does not lead to an abrupt inception of the Grenland Ice Sheet (GrIS). High ablation rates in Central and North Greenland combined with low accumulation prevent such an abrupt inception. Ice sheet inception occurs when combining low summer insolation and CO2 levels below modern values, the GrIS being restricted to the Southeast region where high topography favors this build-up. This ice sheet experiences only partial melting during summer insolation maxima combined with high CO2. Further growth of the ice sheet with recoupling experiments is important at 360 ppm and 280 ppm during insolation minima. Thus, the full glaciation at 2.6 Ma could be the result of a cumulative build-up of the GrIS over several orbital cycles, leading to progressively more intense glaciations during low summer insolation periods. Although this result could be a shortcoming of the modeling framework itself, the gradual glacial inception interpreted from the oxygen isotope record could support our scenario

    13C-assisted metabolic flux analysis to investigate heterotrophic and mixotrophic metabolism in Cupriavidus necator H16

    Get PDF
    Introduction. Cupriavidus necator H16 is a gram-negative bacterium, capable of lithoautotrophic growth by utilizing hydrogen as an energy source and fixing carbon dioxide (CO2) through Calvin-Benson-Bassham (CBB) cycle. The potential to utilize synthesis gas (Syngas) and the prospects of rerouting carbon from polyhydroxybutyrate synthesis to value-added compounds makes C. necator an excellent chassis for industrial application. Objectives. In the context of lack of sufficient quantitative information of the metabolic pathways and to advance in rational metabolic engineering for optimized product synthesis in C. necator H16, we carried out a metabolic flux analysis based on steady-state 13C-labelling. Methods. In this study, steady-state carbon labelling experiments, using either D-[1-13C]fructose or [1,2-13C]glycerol, were undertaken to investigate the carbon flux through the central carbon metabolism in C. necator H16 under heterotrophic and mixotrophic growth conditions, respectively. Results. We found that the CBB cycle is active even under heterotrophic condition, and growth is indeed mixotrophic. While Entner-Doudoroff (ED) pathway is shown to be the major route for sugar degradation, tricarboxylic acid (TCA) cycle is highly active in mixotrophic condition. Enhanced flux is observed in reductive pentose phosphate pathway (redPPP) under the mixotrophic condition to supplement the precursor requirement for CBB cycle. The flux distribution was compared to the mRNA abundance of genes encoding enzymes involved in key enzymatic reactions of the central carbon metabolism. Conclusion. This study leads the way to establishing 13C-based quantitative fluxomics for rational pathway engineering in C. necator H16

    Optical Control of Mammalian Endogenous Transcription and Epigenetic States

    Get PDF
    The dynamic nature of gene expression enables cellular programming, homeostasis, and environmental adaptation in living systems. Dissection of causal gene functions in cellular and organismal processes therefore necessitates approaches that enable spatially and temporally precise modulation of gene expression. Recently, a variety of microbial and plant-derived light-sensitive proteins have been engineered as optogenetic actuators, enabling high precision spatiotemporal control of many cellular functions1-11. However, versatile and robust technologies that enable optical modulation of transcription in the mammalian endogenous genome remain elusive. Here, we describe the development of Light-Inducible Transcriptional Effectors (LITEs), an optogenetic two-hybrid system integrating the customizable TALE DNA-binding domain12-14 with the light-sensitive cryptochrome 2 protein and its interacting partner CIB1 from Arabidopsis thaliana. LITEs do not require additional exogenous chemical co-factors, are easily customized to target many endogenous genomic loci, and can be activated within minutes with reversibility3,4,6,7,15. LITEs can be packaged into viral vectors and genetically targeted to probe specific cell populations. We have applied this system in primary mouse neurons, as well as in the brain of awake mice in vivo to mediate reversible modulation of mammalian endogenous gene expression as well as targeted epigenetic chromatin modifications. The LITE system establishes a novel mode of optogenetic control of endogenous cellular processes and enables direct testing of the causal roles of genetic and epigenetic regulation in normal biological processes and disease states
    corecore