The new tailored nanoporous carbons from the common polypody (Polypodium vulgare): The role of textural properties for enhanced CO2 adsorption

The one-step synthesis of new tailored nanoporous carbons (NCs) from the common polypody (Polypodium vulgare) as feedstock for the first time was presented. The significance of nitrogen flow (2.25 – 30 dm3/h) and temperature (500 – 900 °C) during carbonization was investigated. KOH activated NCs have a high specific surface area (1994 m2/g), large total pore volume (0.998 cm3/g), and micropore volume (0.923 cm3/g). NCs displayed tailored textural properties for CO2 capture. The NCs showed superior CO2 adsorption at 1 bar equal to 5.67 and 9.05 mmol/g, for 298 and 273 K, respectively. The selectivity of CO2 adsorption in relation to N2 was also high. The selectivity coefficient was achieved to 23 and SIAST selectivity 59.5. The isosteric heat of adsorption calculated on the basis of the Clausius-Clapeyron equation and Sips model was ranged from 26 to 31 kJ/mol and suggested the physisorption mechanism of adsorption.Peer ReviewedPostprint (published version

Measuring similarities between transcription factor binding sites

BACKGROUND: Collections of transcription factor binding profiles (Transfac, Jaspar) are essential to identify regulatory elements in DNA sequences. Subsets of highly similar profiles complicate large scale analysis of transcription factor binding sites. RESULTS: We propose to identify and group similar profiles using two independent similarity measures: χ(2 )distances between position frequency matrices (PFMs) and correlation coefficients between position weight matrices (PWMs) scores. CONCLUSION: We show that these measures complement each other and allow to associate Jaspar and Transfac matrices. Clusters of highly similar matrices are identified and can be used to optimise the search for regulatory elements. Moreover, the application of the measures is illustrated by assigning E-box matrices of a SELEX experiment and of experimentally characterised binding sites of circadian clock genes to the Myc-Max cluster

Tri-Frequency Synthetic Aperture Radar for the Measurements of Snow Water Equivalent

A new airborne synthetic aperture radar (SAR) system was recently developed for the estimation of snow water equivalent (SWE). The radar is part of the SWESARR (Snow Water Equivalent Synthetic Aperture Radar and Radiometer) instrument, an active passive microwave system specifically designed for the accurate estimation of SWE. The dual polarization (VV, VH) radar operates at three frequency bands (9.65 GHz, 13.6 GHz, and 17.25 GHz), with bandwidths of up to 200 MHz. The radar flew its first flight campaign in November 2019, along with SWESARRs - already operational radiometer. The radar collected comprehensive data sets over various terrains that show a successful system performance. The inst slated to participate in future SnowEx campaigns

Tri-Frequency Synthetic Aperture Radar for the Measurements of Snow Water Equivalent

SWESARR (Snow Water Equivalent Synthetic Aperture Radar and Radiometer) is an airborne instrument developed at the NASA Goddard Space Flight Center for the retrieval of Snow Water Equivalent. SWESARR was specifically designed to measure co-located active and passive signals using a high resolution and multi-frequency Synthetic Aperture Radar (SAR) and a multifrequency radiometer. SWESARRs Synthetic Aperture Radar (SAR) system is made up of three independent radar units that operate in the X, Ku-Low, and Ku-High bands with bandwidths up to 200 MHz, and acquires data in two polarizations (dual-polarization radar). The difference in sensitivity of the backscatter signals to snow microstructure, in conjunctions with radiometer measurements, permits an accurate estimation of the snow water equivalent (SWE)

Analyse et compensation des imperfections des blocs élémentaires d'un convertisseur modulateur sigma-delta à temps continu en technologie AsGa

La conception des modulateurs sigma-delta passe bande à temps continu, dédiés à la conversion analogique-numérique de signaux radiofréquences, se heurte à de nombreuses difficultés car les technologies sont utilisées aux limites de leurs possibilités. Les imperfections résultant de la réalisation au niveau circuit des blocs fonctionnels idéaux sont susceptibles de dégrader considérablement les performances. Cet article analyse l'influence de deux imperfections (les termes passe-bas des résonateurs à temps continus et la bande passante du sommateur) et propose des solutions de compensation génériques. A titre d'illustration, la démarche est mise en oeuvre pour la conception d'un modulateur d'ordre 6 prévu pour fonctionner à une fréquence de sur-échantillonnage de 3 GHz, pour une fréquence centrale de 750 MHz et une largeur de bande d'environ 10 MHz. Des résultats obtenus par simulation au niveau transistor en technologie AsGa HEMT 0.2, sont présentés

TransFind—predicting transcriptional regulators for gene sets

The analysis of putative transcription factor binding sites in promoter regions of coregulated genes allows to infer the transcription factors that underlie observed changes in gene expression. While such analyses constitute a central component of the in-silico characterization of transcriptional regulatory networks, there is still a lack of simple-to-use web servers able to combine state-of-the-art prediction methods with phylogenetic analysis and appropriate multiple testing corrected statistics, which returns the results within a short time. Having these aims in mind we developed TransFind, which is freely available at http://transfind.sys-bio.net/

Expression profile and transcription factor binding site exploration of imprinted genes in human and mouse

<p>Abstract</p> <p>Background</p> <p>In mammals, imprinted genes are regulated by an epigenetic mechanism that results in parental origin-specific expression. Though allele-specific regulation of imprinted genes has been studied for several individual genes in detail, little is known about their overall tissue-specific expression patterns and interspecies conservation of expression.</p> <p>Results</p> <p>We performed a computational analysis of microarray expression data of imprinted genes in human and mouse placentae and in a variety of adult tissues. For mouse, early embryonic stages were also included. The analysis reveals that imprinted genes are expressed in a broad spectrum of tissues for both species. Overall, the relative tissue-specific expression levels of orthologous imprinted genes in human and mouse are not highly correlated. However, in both species distinctive expression profiles are found in tissues of the endocrine pathways such as adrenal gland, pituitary, pancreas as well as placenta. In mouse, the placental and embryonic expression patterns of imprinted genes are highly similar. Transcription factor binding site (TFBS) prediction reveals correlation of tissue-specific expression patterns and the presence of distinct TFBS signatures in the upstream region of human imprinted genes.</p> <p>Conclusion</p> <p>Imprinted genes are broadly expressed pre- and postnatally and do not exhibit a distinct overall expression pattern when compared to non-imprinted genes. The relative expression of most orthologous gene pairs varies significantly between human and mouse suggesting rapid species-specific changes in gene regulation. Distinct expression profiles of imprinted genes are confined to certain human and mouse hormone producing tissues, and placentae. In contrast to the overall variability, distinct expression profiles and enriched TFBS signatures are found in human and mouse endocrine tissues and placentae. This points towards an important role played by imprinted gene regulation in these tissues.</p

Estimation of extreme values, with application to uncertain systems

International audienceExtreme events are defined as extreme high (or low) values of whatever statistics of the output of the system we are interested in. These values play an important role because they may correspond to abnormal or dangerous operating conditions. Classical statistical inference techniques provide a good description of central behaviour, but not of extreme events. This was our motivation for resorting to extreme-value theory, which provides a framework and tools to model these extreme events. We show in this paper how some of these tools can be used in the context of system reliability, and the resulting methodology is illustrated on an example of circuit design, representative of a wide new field of applications for extreme-value theory

HuSiDa—the human siRNA database: an open-access database for published functional siRNA sequences and technical details of efficient transfer into recipient cells

Small interfering RNAs (siRNAs) have become a standard tool in functional genomics. Once incorporated into the RNA-induced silencing complex (RISC), siRNAs mediate the specific recognition of corresponding target mRNAs and their cleavage. However, only a small fraction of randomly chosen siRNA sequences is able to induce efficient gene silencing. In common laboratory practice, successful RNA interference experiments typically require both, the labour and cost-intensive identification of an active siRNA sequence and the optimization of target cell line-specific procedures for optimal siRNA delivery. To optimize the design and performance of siRNA experiments, we have established the human siRNA database (HuSiDa). The database provides sequences of published functional siRNA molecules targeting human genes and important technical details of the corresponding gene silencing experiments, including the mode of siRNA generation, recipient cell lines, transfection reagents and procedures and direct links to published references (PubMed). The database can be accessed at http://www.human-siRNA-database.net. We used the siRNA sequence information stored in the database for scrutinizing published sequence selection parameters for efficient gene silencing