Polynomial Chaos Expansion for Probabilistic Uncertainty Propagation

Uncertainty propagation (UP) methods are of great importance to design optimization under uncertainty. As a well-known and rigorous probabilistic UP approach, the polynomial chaos expansion (PCE) technique has been widely studied and applied. However, there is a lack of comprehensive overviews and studies of the latest advances of the PCE methods, and there is still a large gap between the academic research and engineering application for PCE due to its high computational cost. In this chapter, latest advances of the PCE theory and method are elaborated, in which the newly developed data-driven PCE method that does not depend on the complete information of input probabilistic distribution as the common PCE approaches is introduced and improved. Meanwhile, the least angle regression technique and the trust region scenario are, respectively, extended to reduce the computational cost of data-driven PCE to accommodate it to practical engineering design applications. In addition, comprehensive comparisons are made to explore the relative merits of the most commonly used PCE approaches in the literature to help designers to choose more suitable PCE techniques in probabilistic design optimization

Reservoir and lithofacies shale classification based on NMR logging

© 2020 Chinese Petroleum Society Shale gas reservoirs have fine-grained textures and high organic contents, leading to complex pore structures. Therefore, accurate well-log derived pore size distributions are difficult to acquire for this unconventional reservoir type, despite their importance. However, nuclear magnetic resonance (NMR) logging can in principle provide such information via hydrogen relaxation time measurements. Thus, in this paper, NMR response curves (of shale samples) were rigorously mathematically analyzed (with an Expectation Maximization algorithm) and categorized based on the NMR data and their geology, respectively. Thus the number of the NMR peaks, their relaxation times and amplitudes were analyzed to characterize pore size distributions and lithofacies. Seven pore size distribution classes were distinguished; these were verified independently with Pulsed-Neutron Spectrometry (PNS) well-log data. This study thus improves the interpretation of well log data in terms of pore structure and mineralogy of shale reservoirs, and consequently aids in the optimization of shale gas extraction from the subsurface

Effect of compression reduction on deformation of CaO‐CaS‐Al 2 O 3 ‐MgO inclusions in solid and semi‐solid steel

Plain strain deformation was performed on solid steel samples at 1473 K and semi‐solid samples at 1743 K. The deformation of inclusions under the reductions of 10%, 20%, and 30% was studied. In the solid steel deformed at 1473 K, the average aspect ratio of inclusions increased from 1.23 in the original slab to 2.07, 2.23, and 2.30 under the reduction of 10%, 20%, and 30%. The deformation of inclusions in the semi‐solid steel was hardly influenced by the reduction. The deformation of inclusions was much more in the solid steel than that in the semi‐solid steel in the current study. Inclusion deformation was explained by the difference of hardness between the inclusion phase and the steel matrix. Stress‐strain curves during deformations indicated that the semi‐solid steel matrix at 1743 K was much softer than the solid steel matrix at 1473 K. Compared to the composition of inclusions in the original slab, the CaS content of inclusions in steel samples deformed at 1473 K was higher, while it was lower in the samples deformed at 1743 K. The CaO content changed inversely. Inclusions in steel samples deformed at 1473 K were a little harder than those in steel samples deformed at 1743 K due to the thicker CaS shell formed in the outer layer. The composition transformation of inclusions was mainly caused by the change of the thermodynamic equilibrium between the steel matrix and inclusions at various temperatures. In the solid steel at 1473 K, the strain concentrated on the soft calcium aluminate phase, resulting in a higher deformation amount of inclusions. In the semi‐solid steel at 1743 K, the soft steel matrix deformed more than inclusions, leading in turn to a smaller deformation of inclusions

Effect of thermal history on the deformation of non-metallic inclusions during plain strain compression

The deformation of inclusions in the steel was affected by the thermal history during the physical simulation of steel processing. After plain strain compression with a reduction of 30%, the average aspect ratio of inclusions in the steel sample cooled down to 1673 K from semi-solid state was 1.89, which was significantly higher than 1.29 in the steel sample heated persistently up to the same temperature. The mechanism was revealed by inclusion transformation

The structure and function of the replication terminator protein of Bacillus subtilis: identification of the 'winged helix' DNA-binding domain.

The replication terminator protein (RTP) of Bacillus subtilis impedes replication fork movement in a polar mode upon binding as two interacting dimers to each of the replication termini. The mode of interaction of RTP with the terminus DNA is of considerable mechanistic significance because the DNA-protein complex not only localizes the helicase-blocking activity to the terminus, but also generates functional asymmetry from structurally symmetric protein dimers. The functional asymmetry is manifested in the polar impedance of replication fork movement. Although the crystal structure of the apoprotein has been solved, hitherto there was no direct evidence as to which parts of RTP were in contact with the replication terminus. Here we have used a variety of approaches, including saturation mutagenesis, genetic selection for DNA-binding mutants, photo cross-linking, biochemical and functional characterizations of the mutant proteins, and X-ray crystallography, to identify the regions of RTP that are either in direct contact with or are located within 11 angstroms of the replication terminus. The data show that the unstructured N-terminal arm, the alpha3 helix and the beta2 strand are involved in DNA binding. The mapping of amino acids of RTP in contact with DNA, confirms a 'winged helix' DNA-binding motif

Spin Crossover in a Series of Non-Hofmann-Type Fe(II) Coordination Polymers Based on [Hg(SeCN)3]-; or [Hg(SeCN)4]2-; Building Blocks

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.inorgchem.1c00802.[EN] Self-assembly of [Hg(SeCN)(4)](2)-tetrahedral building blocks, iron(II) ions, and a series of bis-monodentate pyridyltype bridging ligands has afforded the new heterobimetallic Hg-II-Fe-II coordination polymers {Fe[Hg(SeCN)(3)](2)(4,4'-bipy)(2)}(n) (1), {Fe[Hg(SeCN)(4)](tvp)}(n) (2), {Fe[Hg(SeCN)(3)](2)(4,4'-azpy)(2)}(n) (3), {Fe[Hg(SeCN)(4)](4,4'-azpy)(MeOH)} n (4), {Fe[Hg(SeCN)(4)](3,3'- bipy)} n (5) and {Fe[Hg(SeCN)4](3,3'-azpy)}(n) (6) (4,4-bipy = 4,4'-bipyridine, tvp = trans-1,2-bis(4-pyridyl)ethylene, 4,4'-azpy = 4,4'-azobispyridine, 3,3-bipy = 3,3'bipyridine, 3,3'-azpy = 3,3'-azobispyridine). Single-crystal X-ray analyses show that compounds 1 and 3 display a two-dimensional robust sheet structure made up of infinite linear [(FeL)n]2n+ (L = 4,4'-bipy or 4,4'-azpy) chains linked by in situ formed {[Hg(L)(SeCN)(3)](2)}(2)-anionic dimeric bridges. Complexes 2 and 4-6 define three-dimensional networks with different topological structures, indicating, in combination with complexes 1 and 3, that the polarity, length, rigidity, and conformation of the bridging organic ligand play important roles in the structural nature of the products reported here. The magnetic properties of complexes 1 and 2 show the occurrence of temperature-and light-induced spin crossover (SCO) properties, while complexes 4-6 are in the high-spin state at all temperatures. The current results provide a new route for the design and synthesis of new SCO functional materials with non-Hofmann-type traditional structures.This work was supported by the Natural Science Foundation of China (21671121and 21773006), the Spanish Ministerio de Ciencia e Innovacion (MICINN) and FEDER funds (PID2019-106147GB-I00), and Unidad de Excelencia Maria de Maeztu (CEX2019-000919-M).Cao, T.; Valverde-Muñoz, FJ.; Duan, X.; Zhang, M.; Wang, P.; Xing, L.; Sun, F.... (2021). Spin Crossover in a Series of Non-Hofmann-Type Fe(II) Coordination Polymers Based on [Hg(SeCN)3]-; or [Hg(SeCN)4]2-; Building Blocks. Inorganic Chemistry. 60(15):11048-11057. https://doi.org/10.1021/acs.inorgchem.1c008021104811057601

Prognostic Value of CD44 and Its Isoforms in Advanced Cancer: A Systematic Meta-Analysis With Trial Sequential Analysis

Objective: Cancer stem cell marker CD44 and its variant isoforms (CD44v) may be correlated with tumor growth, metastasis, and chemo-radiotherapy resistance. However, the prognostic power of CD44 and CD44v in advanced cancer remains controversial. Therefore, the purpose of our study was to generalize the prognostic significance of these cancer stem cell markers in advanced cancer patients.Methods: Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated from multivariable analysis to assess the associations among CD44, CD44v6, and CD44v9 positivity and overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), cancer-specific survival (CSS), and recurrence-free survival (RFS). Trial sequential analysis (TSA) was also conducted.Results: We included 15 articles that reported on 1,201 patients with advanced cancer (CD44: nine studies with 796 cases, CD44v6: three studies with 143 cases, and CD44v9: three studies with 262 cases). CD44 expression was slightly linked to worse OS (HR = 2.03, P = 0.027), but there was no correlation between CD44 expression and DFS, RFS, or PFS. Stratified analysis showed that CD44 expression was not correlated with OS at ≥5 years or OS in patients receiving adjuvant therapy. CD44v6 expression was not associated with OS. CD44v9 expression was closely associated with poor 5-years CSS in patients treated with chemo/radiotherapy (HR = 3.62, P < 0.001). However, TSA suggested that additional trials were needed to confirm these conclusions.Conclusions: CD44 or CD44v9 might be novel therapeutic targets for improving the treatment of advanced cancer patients. Additional prospective clinical trials are strongly needed across different cancer types