Comparison of three radio-frequency discharge modes on the treatment of breast cancer cells in vitro

Non-thermal plasmas (NTPs) are known for their ability to induce thermal-free cytotoxic effects on cancer cells. However, as the variety of NTP devices increases, comparison of their cytotoxic effect becomes increasingly essential. In this work, we compare the cytotoxicity of three different radio-frequency NTPs. MDA-MB-231 triple negative breast cancer cells are treated in suspension in DMEM culture medium by the effluents of a single radiofrequency (RF) discharge device operating in three modes, namely the and modes of the capacitively coupled radio-frequency (CCRF) discharge and a RF plasma jet mode. All three discharge modes reduce the proliferative capacity of MDA-MB-231 cells, but the treatment time required to reach the same efficacy is more than ten times longer using the and the modes than using the jet mode. In all cases, using the appropriate treatment time, cells exhibit an impaired proliferation and eventually start to show signs of cell death (about 48 h after treatment). The three discharge modes also induce nuclear DNA damages. Plasma-produced H2O2 was not found to contribute to the cytotoxicity of the treatment. Furthermore, short-lived reactive species (gas phase or liquid phase species with a lifetime below 1 s) are expected to play a dominant role over the long-lived reactive species in the anti-cancer effect of all three discharge modes

Assemblage adaptatif de génomes et de méta-génomes par passage de messages

De manière générale, les procédés et processus produisent maintenant plus de données qu’un humain peut en assimiler. Les grosses données (Big Data), lorsque bien analysées, augmentent la compréhension des processus qui sont opérationnels à l’intérieur de systèmes et, en conséquence, encouragent leur amélioration. Analyser les séquences de l’acide désoxyribonucléique (ADN) permet de mieux comprendre les êtres vivants, en exploitant par exemple la biologie des systèmes. Les séquenceurs d’ADN à haut débit sont des instruments massivement parallèles et produisent beaucoup de données. Les infrastructures informatiques, comme les superordinateurs ou l’informatique infonuagique, sont aussi massivement parallèles de par leur nature distribuée. Par contre, les ordinateurs ne comprennent ni le français, ni l’anglais – il faut les programmer. Les systèmes logiciels pour analyser les données génomiques avec des superordinateurs doivent être aussi massivement parallèles. L’interface de passage de messages permet de créer de tels logiciels et une conception granulaire permet d’entrelacer la communication et le calcul à l’intérieur des processus d’un système de calcul. De tels systèmes produisent des résultats rapidement à partir de données. Ici, les logiciels RayPlatform, Ray (incluant les flux de travail appelé Ray Meta et Ray Communities) et Ray Cloud Browser sont présentés. L’application principale de cette famille de produits est l’assemblage et le profilage adaptatifs de génomes par passage de messages.Generally speaking, current processes – industrial, for direct-to-consumers, or researchrelated – yield far more data than humans can manage. Big Data is a trend of its own and concerns itself with the betterment of humankind through better understanding of processes and systems. To achieve that end, the mean is to leverage massive amounts of big data in order to better comprehend what they contain, mean, and imply. DNA sequencing is such a process and contributes to the discovery of knowledge in genetics and other fields. DNA sequencing instruments are parallel objects and output unprecedented volumes of data. Computer infrastructures, cloud and other means of computation open the door to the analysis of data stated above. However, they need to be programmed for they are not acquainted with natural languages. Massively parallel software must match the parallelism of supercomputers and other distributed computing systems before attempting to decipher big data. Message passing – and the message passing interface – allows one to create such tools, and a granular design of blueprints consolidate production of results. Herein, a line of products that includes RayPlatform, Ray (which includes workflows called Ray Meta and Ray Communities for metagenomics) and Ray Cloud Browser are presented. Its main application is scalable (adaptive) assembly and profiling of genomes using message passing

Transition des basses fréquences aux hautes fréquences d’une décharge à barrière diélectrique en hélium à la pression atmosphérique

Réalisée en cotutelle avec l'Université de PerpignanLes décharges à barrière diélectrique homogènes à la pression atmosphérique représentent un véritable intérêt autant pour les applications industrielles que pour la richesse de leur comportement physique. Jusqu’à maintenant, la gamme des basses fréquences (sous 300 kHz) et la gamme des hautes fréquences (au-dessus de 3 MHz) ont été amplement étudiées ; la physique contrôlant la décharge est donc relativement bien connue. Par contre, la gamme des moyennes fréquences (entre 0,3 et 3 MHz) reste à ce jour très peu explorée. Cette thèse par article vise, dans un premier temps, à comprendre le fonctionnement de la décharge à barrière diélectrique dans la gamme des moyennes fréquences. Dans un deuxième temps, l’effet de la fréquence sur la décharge est étudié sur la plage des basses aux hautes fréquences. Cette recherche expérimentale est poursuivie à l’aide d’une décharge à barrière diélectrique dans une atmosphère contrôlée d’hélium à la pression atmosphérique. Afin d’identifier les multiples régimes de décharge, plusieurs diagnostics sont mis en oeuvre. L’imagerie rapide est d’abord employée pour permettre l’identification des régimes de décharge en fonction de leur évolution temporelle. Ensuite, des mesures électriques, de la spectroscopie d’émission optique et de la spectroscopie d’absorption sont utilisées de manière à déterminer la densité électronique, la température électronique ainsi que la densité des atomes dans un état métastable. Pour une fréquence d’excitation fixe dans la gamme des moyennes fréquences, la décharge peut se comporter selon deux régimes distincts. Ceux-ci sont identifiés comme le régime Ω, pour lequel l’ionisation se produit au centre de la décharge et la densité de puissance est d’environ 0,1W/cm3, et le régime hybride, pour lequel l’ionisation se produit dans les gaines et la densité de puissance est d’environs 10W/cm3. Lorsque la fréquence est supérieure à 1MHz, le passage du régime Ω au régime hybride est accompagné d’une hystérèse. Cette hystérèse est due au piégeage efficace des ions dans l’espace interdielectrique qui ne permet pas aux ions de participer à l’émission secondaire tant que la charge d’espace n’est pas suffisante pour déformer le champ électrique. Quant aux fréquences inférieures à 1MHz, le régime hybride qui leur est associé n’est pas maintenu de manière continue, mais transite spontanément entre les régimes Ω et hybride. Un phénomène qui est dû au piégeage des ions qui n’est pas encore suffisant pour conserver les ions dans la gaine dans le cas où le champ électrique est perturbé par la charge d’espace. De plus, sur toute la gamme de fréquences étudiée (de 25kHz à 15MHz), il est possible de générer plusieurs autres régimes de décharge homogènes. Jusqu’à 100 kHz, en plus du régime luminescent (pour lequel l’ionisation est maximum près de la cathode) habituellement observé en basses fréquences, un régime dit quasi-Townsend, pour lequel l’ionisation est à son maximum près de l’anode a pu être observé. Entre 200 et 3000 kHz, ce sont les régimes Ω et hybride qui sont observés. À partir de 5 MHz, le régime RF-α est finalement atteint. Sur la plage de fréquence étudiée, la densité électronique moyenne (intégrée spatialement et temporellement) varie de e14 à e17 /m3 tandis que la température électronique moyenne se situe entre 0.3 et 0,5 eV. Tout comme la température électronique, la densité des atomes dans un état métastable est maximale dans le régime hybride.Atmospheric-pressure diffuse discharges are of great interest both for their physical complexity as well as for their numerous industrial applications. A good method to generate diffuse discharges at atmospheric pressure is by means of a dielectric barrier discharge. Up to now, the low frequency range (below 300kHz) and the high-frequency range (above 3 MHz) have been vastly studied, leaving the medium frequency range (between 0.3 and 3 MHz) almost empty of experimental data. The aim of this thesis by publications is two fold. First, the discharge modes obtained in the medium frequency range are to be understood and characterized. Second, the influence of the excitation frequency on the discharge is studied over a wide spectrum (from 25 kHz to 15 MHz). This includes frequencies from the very-low-frequency range to the high-frequency range. The experimental investigation is undertaken with a dielectric barrier discharge in a well-controlled environment of helium at atmospheric pressure. In order to identify the multiple discharge modes, many diagnostics are performed. Fast imaging is used to identify discharge modes according to their time evolution. Then electrical measurements, optical emission spectroscopy and absorption spectroscopy are deployed to measure the electron density, the electron temperature and the density of atoms in a metastable state respectively. At a fix excitation frequency in the medium-frequency range, two distinct discharge modes occur. The first one is identified as the Ω mode in which ionization is at the centre of the discharge and the power density is about 0.1W/cm3. The second one is identified as the hybrid mode in which ionization mainly occurs in the sheath region and the power density can reach about 10W/cm3. When the frequency is above 1MHz, the transition from Ω mode to hybrid mode is subject to a hysteresis. This hysteresis is due to efficient trapping of ions in the gas gap which does not allow ions to participate in secondary electron emission as long as the space charge is too low to modify the applied electric field. However, when the frequency is below 1 MHz the hybrid mode can no longer be sustained continuously but rather oscillate spontaneously between the Ω and the hybrid mode. This phenomenon is due to less efficient ion trapping that cannot maintain ions in the sheath when the electric field is modified by the space charge. Furthermore, over the entire investigated frequency range, many other diffuse discharge modes are sustained. In addition to the atmospheric pressure glow discharge (in which maximum ionization occurs on the cathode side) usually observed in the low-frequency range, a Townsend-like mode is also generated at frequencies about 100kHz. In this case, the maximum ionization occurs on the anode side. From 200 to 3000kHz, the Ω and the hybrid mode are achieved. Finally, from 5 MHz, the usual RF-α mode is reached. Over the complete range of frequency investigated, the mean electron density (time and spatially averaged) increase from e14 to e17/m3 while the electron temperature ranges between 0.3 and 0.5 eV. Both electronic temperature and density of atoms in a metastable state are maximum in the hybrid mode

A simple high-speed random number generator with minimal post-processing using a random Raman fiber laser

ABSTRACT: A simple novel method for random number generation is presented, based on a random Raman fiber laser. This laser is built in a half-open cavity scheme, closed on one side by a narrow-linewidth 100 mm fiber Bragg grating. The interaction between the randomly excited lasing modes of this laser, in addition to nonlinear effects such as modulation instability, allow the generation of random bits at rates of up to 540 Gbps with minimal post processing. Evaluation of the resulting bit streams’ randomness by the NIST statistical test suite highlights the importance of evaluating the physical entropy content, as bit sequences generated by this random laser pass all the statistical tests with a significance level of 0.01, despite being generated at more than twice the theoretical entropy generation speed

Genome-wide gene expression profiling analysis of Leishmania major and Leishmania infantum developmental stages reveals substantial differences between the two species

<p>Abstract</p> <p>Background</p> <p><it>Leishmania </it>parasites cause a diverse spectrum of diseases in humans ranging from spontaneously healing skin lesions (e.g., <it>L. major</it>) to life-threatening visceral diseases (e.g., <it>L. infantum</it>). The high conservation in gene content and genome organization between <it>Leishmania major </it>and <it>Leishmania infantum </it>contrasts their distinct pathophysiologies, suggesting that highly regulated hierarchical and temporal changes in gene expression may be involved.</p> <p>Results</p> <p>We used a multispecies DNA oligonucleotide microarray to compare whole-genome expression patterns of promastigote (sandfly vector) and amastigote (mammalian macrophages) developmental stages between <it>L. major </it>and <it>L. infantum</it>. Seven per cent of the total <it>L. infantum </it>genome and 9.3% of the <it>L. major </it>genome were differentially expressed at the RNA level throughout development. The main variations were found in genes involved in metabolism, cellular organization and biogenesis, transport and genes encoding unknown function. Remarkably, this comparative global interspecies analysis demonstrated that only 10–12% of the differentially expressed genes were common to <it>L. major </it>and <it>L. infantum</it>. Differentially expressed genes are randomly distributed across chromosomes further supporting a posttranscriptional control, which is likely to involve a variety of 3'UTR elements.</p> <p>Conclusion</p> <p>This study highlighted substantial differences in gene expression patterns between <it>L. major </it>and <it>L. infantum</it>. These important species-specific differences in stage-regulated gene expression may contribute to the disease tropism that distinguishes <it>L. major </it>from <it>L. infantum.</it></p

Structural and optical properties of Nd:YAB-nanoparticle-doped PDMS elastomers for random lasers

ABSTRACT: We report the structural and optical properties of Nd:YAB (NdxY1−x Al3(BO3)4)-nanoparticle-doped PDMS elastomer films for random lasing (RL) applications. Nanoparticles with Nd ratios of x = 0.2, 0.4, 0.6, 0.8, and 1.0 were prepared and then incorporated into the PDMS elastomer to control the optical gain density and scattering center content over a wide range. The morphology and thermal stability of the elastomer composites were studied. A systematic investigation of the lasing wavelength, threshold, and linewidth of the laser was carried out by tailoring the concentration and optical gain of the scattering centers. The minimum threshold and linewidth were found to be 0.13 mJ and 0.8 nm for x = 1 and 0.8. Furthermore, we demonstrated that the RL intensity was easily tuned by controlling the degree of mechanical stretching, with strain reaching up to 300%. A strong, repeatable lasing spectrum over ~ 50 cycles of applied strain was observed, which demonstrates the high reproducibility and robustness of the RL. In consideration for biomedical applications that require long-term RL stability, we studied the intensity fluctuation of the RL emission, and confirmed that it followed Lévy-like statistics. Our work highlights the importance of using rare-earth doped nanoparticles with polymers for RL applications

CHD2 haploinsufficiency is associated with developmental delay, intellectual disability, epilepsy and neurobehavioural problems

BACKGROUND: The chromodomain helicase DNA binding domain (CHD) proteins modulate gene expression via their ability to remodel chromatin structure and influence histone acetylation. Recent studies have shown that CHD2 protein plays a critical role in embryonic development, tumor suppression and survival. Like other genes encoding members of the CHD family, pathogenic mutations in the CHD2 gene are expected to be implicated in human disease. In fact, there is emerging evidence suggesting that CHD2 might contribute to a broad spectrum of neurodevelopmental disorders. Despite growing evidence, a description of the full phenotypic spectrum of this condition is lacking. METHODS: We conducted a multicentre study to identify and characterise the clinical features associated with haploinsufficiency of CHD2. Patients with deletions of this gene were identified from among broadly ascertained clinical cohorts undergoing genomic microarray analysis for developmental delay, congenital anomalies and/or autism spectrum disorder. RESULTS: Detailed clinical assessments by clinical geneticists showed recurrent clinical symptoms, including developmental delay, intellectual disability, epilepsy, behavioural problems and autism-like features without characteristic facial gestalt or brain malformations observed on magnetic resonance imaging scans. Parental analysis showed that the deletions affecting CHD2 were de novo in all four patients, and analysis of high-resolution microarray data derived from 26,826 unaffected controls showed no deletions of this gene. CONCLUSIONS: The results of this study, in addition to our review of the literature, support a causative role of CHD2 haploinsufficiency in developmental delay, intellectual disability, epilepsy and behavioural problems, with phenotypic variability between individuals