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Fromm M.,UNL
Current Opinion in Plant Biology | Year: 2014

Despite the proven correlation between gene transcriptional activity and the levels of tri-methyl marks on histone 3 lysine4 (H3K4me3) of their nucleosomes, whether H3K4me3 contributes to, or 'registers', activated transcription is still controversial. Other questions of broad relevance are whether histone-modifying proteins are involved in the recruitment of Pol II and the general transcription machinery and whether they have roles other than their enzyme activities. We address these questions as well as the roles of the ARABIDOPSIS HOMOLOG OF TRITHORAX1 (ATX1), of the COMPASS-related (AtCOMPASS) protein complex, and of their product, H3K4me3, at ATX1-dependent genes. We suggest that the ambiguity about the role of H3K4me3 as an activating mark is due to the unknown duality of the ATX1/AtCOMPASS to facilitate PIC assembly and to generate H3K4me3, which is essential for activating transcriptional elongation. © 2014 . Source

Rondao R.,University of Coimbra | Seixas De Melo J.,University of Coimbra | Melo M.J.,UNL | Melo M.J.,New University of Lisbon | Parola A.J.,New University of Lisbon
Journal of Physical Chemistry A | Year: 2012

The photoreaction of indigo and two other derivatives in its reduced (leuco) form was investigated by absorption and fluorescence (steady-state and time-resolved) techniques. The fluorescence quantum yield (φ F) dependence with the UV irradiation time was found to increase up to a value of φ F ≈ 0.2-0.3 (after 16 min) for indigo and φ F = 0.2 (at ∼150 min) for its derivative 4,4′-dibutoxy-7,7′- dimethoxy-5,5′-dinitroindigo (DBMNI). With a model compound, where rotation around the central C-C bond is blocked, the φ F value was found constant with the UV irradiation time. Time-resolved fluorescence revealed that initially the decays are fitted with a biexponential law (with 0.12 and 2.17 ns), ending with an almost monoexponential decay (∼2.17 ns). Quantum yields for the isomerization photoreaction (φ R) were also obtained for indigo and DBMNI with values of 0.9 and 0.007, respectively. The results are rationalized in terms of a photoisomerization (conversion) reaction occurring in the first excited singlet state of trans to cis forms of leuco indigo. © 2012 American Chemical Society. Source

Erdogmus E.,University of Nebraska - Lincoln | Freedland J.,Wiss, Janney, Elstner Associates, Inc. | Kousgaard A.,UNL | Buckley C.M.,UNL
AEI 2013: Building Solutions for Architectural Engineering - Proceedings of the 2013 Architectural Engineering National Conference | Year: 2013

Antioch ad Cragum is an ancient Roman city on the southern Mediterranean coast of Turkey. Erdogmus and a team of archaeologists have been studying the collapsed, ruinous temple of the city since 2005 with the ultimate goal of reconstructing it partially as a historic site. The Temple of Antioch is designated as a Corinthian order, pro-style, platform temple based on the blocks found and studied. The super structure is dry stack masonry, while the foundation is mortared rubble masonry. Samples from mortar in the foundation walls and base were collected for laboratory analysis and findings on this were published previously. During the fieldwork season of 2011, with the consultations of Freedland, detailed assessments on the condition and deterioration of the temple's marble blocks were started. Following were among the detected deterioration causes: lichen (white, black, and orange species), algae, moss, alveolization, white residue, minor surface cracks, and major structural cracks. Furthermore, a novel, nondestructive, quantitative block assessment tool is being developed. The paper presents: methods used to identify the types and extent of damage on the marble blocks; the development of a damage identification booklet, block assessment forms, and block database specific to the project; and some experiments conducted to assess the materials and the deterioration mechanism. The project's conservation efforts are still in its early stages, therefore, future plans are also presented. © 2013 American Society of Civil Engineers. Source

Carrizo M.E.,UNL | Alesso C.A.,UNL | Guedes J.N.,Federal Rural University of Rio de Janeiro | Imhoff S.C.,Kreder 2805
Ciencia del Suelo | Year: 2013

The objectives of this study were to determine the pseudototal and available contents of Cu, Fe, Mn and Zn as well as their speciation in Argiudolls located in the flat Argentine Pampas, in Santa Fe province, and to compare the contents extracted by EDTA with those by a sequential method. Four soils with different soil use intensity were selected for the study. Pseudototal micronutrient contents were determined and their concentrations were estimated by simple (EDTA) and sequential (BCR) extraction methods. The pseudototal average contents of Cu, Fe, Mn and Zn were: 14.4; 14010; 757 and 58.9 mg kg-1, respectively. The EDTA extractable levels were: 4.4; 174.8; 410.6 and 8.4 mg kg-1, respectively. The concentrations of Cu estimated by both methods were similar while higher contents of Fe, Mn and Zn were estimated by the BCR method. Iron, Zn and Cu were mainly found in the residual fraction. About 30% of total Cu was available in the oxidizable fraction and bound to soil organic matter. Zinc was primarily associated with the residual fraction and to a lesser degree to exchangeable, oxidizable and reducible forms. Manganese was mostly linked to the reducible, water-acid soluble and exchangeable fractions. These results confirm that in these soils the availability of all micronutrients determined by the EDTA method are above the critical values for crop growth. Source

Nowak A.S.,UNL | Rakoczy A.M.,UNL | Szeliga E.K.,Warsaw University of Technology
American Concrete Institute, ACI Special Publication | Year: 2011

The objective of this study is to revise the resistance model for calibration of the ACI 318 Code, using the new material test data. The research focused on the development of statistical parameters of the load carrying capacity for reinforced concrete beams, slabs and columns. The considered materials include ordinary concrete and high strength concrete, both cast-in-place and plant-cast. Resistance is considered as a product of three random variables representing the uncertainty in material properties, dimensions and geometry (fabrication factor) and analytical model (professional factor). Material test data is presented in form of the cumulative distribution functions (CDF) plotted on the normal probability paper for an easier interpretation of the results. In addition, the statistical parameters are determined for a normal distribution that is fitted to the lower tail of the CDF. The most important parameters are the mean value, bias factor and the coefficient of variation. It was observed that the quality of materials and workmanship have been improved over the last 30 years and this is reflected in reduced coefficients of variation. The two other parameters, i.e. fabrication and professional factors, are also considered and summarized based on the available literature. The developed resistance models were obtained by Monte Carlo simulations. They can serve as a basis for the selection of resistance factors (strength reduction factors). Source

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