NARROMI: a noise and redundancy reduction technique improves accuracy of gene regulatory network inference.

MOTIVATION: Reconstruction of gene regulatory networks (GRNs) is of utmost interest to biologists and is vital for understanding the complex regulatory mechanisms within the cell. Despite various methods developed for reconstruction of GRNs from gene expression profiles, they are notorious for high false positive rate owing to the noise inherited in the data, especially for the dataset with a large number of genes but a small number of samples. RESULTS: In this work, we present a novel method, namely NARROMI, to improve the accuracy of GRN inference by combining ordinary differential equation-based recursive optimization (RO) and information theory-based mutual information (MI). In the proposed algorithm, the noisy regulations with low pairwise correlations are first removed by using MI, and the redundant regulations from indirect regulators are further excluded by RO to improve the accuracy of inferred GRNs. In particular, the RO step can help to determine regulatory directions without prior knowledge of regulators. The results on benchmark datasets from Dialogue for Reverse Engineering Assessments and Methods challenge and experimentally determined GRN of Escherichia coli show that NARROMI significantly outperforms other popular methods in terms of false positive rates and accuracy. AVAILABILITY: All the source data and code are available at: http://csb.shu.edu.cn/narromi.htm

Preparation and catalytic properties of ZrO2-Al2O3 composite oxide supported nickel catalysts for methane reforming with carbon dioxide

ZrO2-Al2O3 composite oxides and supported Ni catalysts were prepared, and characterized by N-2 adsorption/desorption, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The catalytic performance and carbon deposition was also investigated. This mesoporous composite oxide is shown to be a promising catalyst support. An increase in the catalytic activity and stability of methane and carbon dioxide reforming reaction was resulted from the zirconia addition, especially at 5wt% ZrO2 content. The Ni catalyst supported ZrO2-Al2O3 has a strong resistance to sintering and the carbon deposition in a relatively long-term reaction

Catalytic combustion of soot over Cu-Mg/Al composite oxides

Keeping the atomic ratio of nM2+/nM3+ at 3, series of CuMgAl-O oxides (wCuO=0?, 5?, 10?, 15?, 20?, 30?, 40?,denoted as (0, 5, 10, 15, 20, 30, 40)CMAO respectively) were derived from calcination of Cu substituted Mg/Al-mixed anionic clay precursors(CuMgAl-hydrotalites, CMA-HTs), which were synthesized by co-precipitation methods. XRD, TG-DSC, TPR and FT-IR were used to study the influences of the Cu, Mg content upon the properties of precursors and prepared catalysts. Mg could improve thermal stability of catalysts in some degree. With the increase of Cu content, the surface area of catalysts decreased. However, the surface area was not an important factor in soot catalytic combustion. Activity tests showed the calcination affected the activity of CMAO catalysts significantly, and that 15CMAO-800 was the optimal catalyst for soot catalytic combustion and the T10 and T50 were 336 ? and 409 ? respectively. Moreover, complete structures of hydrotalcite precursors could be formed when wCuO?30?. However, Cu(OH)2 phase appeared when wCuO =40?. When wCuO < 20?, homogeneous composite oxides could be obtained by calcination at 800 ?, but CuO phase was isolated when wCuO?20?. TG-DTA and FT-IR showed that the content of Cu, Mg had significant influences on the thermal decomposition characteristics of CuMgAl-hydrotalcites. TPR results showed that the reduction ability of catalysts was determined by the calcination and composition

Nanoporous silica-supported nanometric palladium: synthesis, characterization, and catalytic deep oxidation of benzene

In this present study, nanoporous silica SBA-15 supported palladium catalysts are prepared through two different methods. The catalysts are employed for catalytic deep oxidation reaction of benzene at a high gas hourly space velocity of 100 000 h-1. It is found that the traditional aqueous impregnation method has some difficulties and disadvantages in obtaining highly dispersed palladium active phases. Whereas, when a grafting procedure is employed, palladium tends to be highly dispersed as nanoparticles due to the confinement of the nanosized pore channels of the support materials. The catalysts prepared via the grafting procedure catalyze the benzene oxidation far more effectively than those prepared via aqueous impregnation method, and complete conversion of benzene can be achieved below 190 °C over the most active catalyst. The nanoporous silica-supported palladium catalysts are promising materials for the control of some types of VOCs such as benzene

Influence of Cu-substituted hydrotalcite precursors and derived oxides

The coprecipitation method was used to prepare a series of different oxides (CuO: 0, 5%, 10%, 15%, 20%, 30% and 40%) derived from Cu substituted Mg/Al-mixed anionic clay precursors (hydrotalcites) at the ratio of M2+/M3+ = 3. In order to study influences of Cu and Mg content upon the performance of these materials, such characterization techniques as X-ray diffraction, thermogravimetrical analysis, differential scanning calorimetry, temperature programmed reaction and Fourier transform infrared reflectance spectra, were used. The results showed that complete structure of hydrotalcite precursors could be formed when CuO ≤ 30%. When CuO ≥ 40%, Cu(OH)(2) phase appeared. Homogeneous composite oxides can be obtained by high temperature calcination at CuO ≤ 20%. When CuO > 20%, CuO phase was isolated. The content of Cu and Mg had significant influences on thermal stability of materials. The reduction ability of materials was related to calcination temperatures and material composition

Preparation of Fe-substituted hexaaluminate and its catalytic performance for methane combustion

Fe-substituted hexaaluminate (BaFexAl12-xO19-delta) was prepared with co-precipitation method followed by hydrothermal treatment. The XRD and SEM results indicated that no hexaaluminate phase was formed when calcined below 1000 degreesC, and hexaaluminate was the dominant phase when calcined above 1100 degreesC. Moreover, the UV-Vis-DR result verified that Fe occupied the Oh sites in Fe-hexaaluminate structure. With the increase of Fe content (xless than or equal to3), the activity of hexaaluminate for methane combustion was raised. The most active catalyst was BaFe3Al9O19-delta, the light-off temperature of which was 515 degreesC. Compared with BaFeAl11O19-delta, the high-temperature activity of Ba0.5La0.5FeAl11O19-delta increased greatly, no obvious promotion for methane ignition activity was observed. The reactant atmosphere had impact on methane ignition activity, but slight influence on high-temperature activity due to the transport limitation. Stability experiment was carried out at 800 degreesC for 100 h, and no deactivation was detected

Effects of La incorporation in Ba1-xLaxFeAl11O19-delta on the performance of methane catalytic combustion

Series of Ba1-xLaxFeAl11O19-delta hexaaluminate catalysts were prepared by (NH4) 2CO3 co-precipitation method and their performance for methane catalytic combustion was studied. The obtained materials were characterized by XRD, Diffuse UV-Vis, FT-IR, TPR, and N-2 BET techniques. The results showed that partial substitution of Ba with La in Fe-hexaaluminates could enhance catalytic activity for methane combustion, and the optimal catalyst was Ba0.2La0.8FeAl11O19-delta hexaaluminate, whose light-off temperature was as low as 495 degreesC denoted by 10% conversion of methane (V-CH4/V-O2/V-N2 = 1/4/95). XRD and SEM characterization indicated that the samples formed well-defined hexaaluminate phase after calcination at 1 200 degreesC for 5 h, and the dopant of La could promote the formation of hexaaluminate phases. UV-Vis-DR characterization revealed that the oxide state of Fe is + 3 in Ba1-xLaxFeAl11O9-delta catalysts. The synergism between Ba, La and Fe was observed based on the results of UV-Vis-DR, FT-IR and TPR