Dynamic modeling of compressed gas energy storage to complement renewable wind power intermittency

To evaluate the impacts and capabilities of large-scale compressed gas energy storage for mitigating wind intermittency, dynamic system models for compressed air energy storage and compressed hydrogen energy storage inside salt caverns have been developed. With the experimental data from air storage in a salt cavern in Huntorf, Germany, the cavern model has been verified. Both daily and seasonal simulation results suggest that with the same size wind farm and salt cavern, a compressed hydrogen energy storage system could better complement the wind intermittency and could also achieve load shifting on a daily and seasonal time scale. Moreover, the hydrogen produced in the compressed hydrogen energy storage system could also be dispatched as a fuel to accommodate zero emission transportation for up to 14,000 fuel cell vehicles per day while achieving seasonal load shifting.     

Leukemia-Induced Cellular Senescence and Stemness Alterations in Mesenchymal Stem Cells Are Reversible upon Withdrawal of B-Cell Acute Lymphoblastic Leukemia Cells

Leukemic cell growth in the bone marrow (BM) induces a very stressful condition. Mesenchymal stem cells (MSC), a key component of this BM niche, are affected in several ways with unfavorable consequences on hematopoietic stem cells favoring leukemic cells. These alterations in MSC during B-cell acute lymphoblastic leukemia (B-ALL) have not been fully studied. In this work, we have compared the modifications that occur in an in vitro leukemic niche (LN) with those observed in MSC isolated from B-ALL patients. MSC in this LN niche showed features of a senescence process, i.e., altered morphology, increased senescence-associated β-Galactosidase (SA-βGAL) activity, and upregulation of p53 and p21 (without p16 expression), cell-cycle arrest, reduced clonogenicity, and some moderated changes in stemness properties. Importantly, almost all of these features were found in MSC isolated from B-ALL patients. These alterations rendered B-ALL cells susceptible to the chemotherapeutic agent dexamethasone. The senescent process seems to be transient since when leukemic cells are removed, normal MSC morphology is re-established, SA-βGAL expression is diminished, and MSC are capable of re-entering cell cycle. In addition, few cells showed low γH2AX phosphorylation that was reduced to basal levels upon cultivation. The reversibility of the senescent process in MSC must impinge important biological and clinical significance depending on cell interactions in the bone marrow at different stages of disease progression in B-ALL.     

Building siRNAs with Cubes: Synthesis and Evaluation of Cubane-Modified siRNAs

Cubane molecules hold great potential for medicinal chemistry applications due to their inherent stability and low toxicity. In this study, we report the synthesis of a cubane derivative phosphoramidite for the incorporation of cubane into small interfering RNAs (siRNAs). Synthetic siRNAs rely on chemical modifications to improve their pharmacokinetic profiles. However, they are still able to mediate sequence-specific gene silencing via the endogenous RNA interference pathway. We designed a library of siRNAs bearing cubane at different positions within the sense and antisense strands. All siRNAs showed excellent gene-silencing activity, with IC₅₀ values ranging from 45.4 to 305 pM. Incorporating the cubane modification in both the sense and antisense strand led to viable duplexes with good biological activity. To the best of our knowledge, this is the first report of siRNAs bearing a cubane derivative within the backbone.     

Experimental testing of ductile cladding connections for building facades

A ductile cladding connection is a special connecting device between a facade cladding panel and a building structure that is designed to dissipate energy when subjected to an earthquake. The effect of such a device is to reduce the overall seismic response of the structure. A special testing machine was designed to test the behavior of these advanced cladding connections. The machine, which is specially suited for the recording and evaluation of ductility and damping properties, is described. Its main characteristics are both the ability to load a specimen in shear simultaneously in two orthogonal directions without inducing any axial stress, and the flexibility to test a wide variety of different damping mechanisms with different geometric configurations. The machine was used to test a family of advanced cladding connections that employs ductile flexural action to achieve high and stable levels of ductility for repeated cyclic load applications. A lumped-parameter mechanical model for these connections was identified from selected test data, and the predicted cyclic behavior was shown to agree well with test data. The model is simple and suitable for incorporation into nonlinear structural analysis programs.     

Separability versus prototypicality in handwritten word-image retrieval

Hit lists are at the core of retrieval systems. The top ranks are important, especially if user feedback is used to train the system. Analysis of hit lists revealed counter-intuitive instances in the top ranks for good classifiers. In this study, we propose that two functions need to be optimised: (a) in order to reduce a massive set of instances to a likely subset among ten thousand or more classes, separability is required. However, the results need to be intuitive after ranking, reflecting (b) the prototypicality of instances. By optimising these requirements sequentially, the number of distracting images is strongly reduced, followed by nearest-centroid based instance ranking that retains an intuitive (low-edit distance) ranking. We show that in handwritten word-image retrieval, precision improvements of up to 35 percentage points can be achieved, yielding up to 100% top hit precision and 99% top-7 precision in data sets with 84 000 instances, while maintaining high recall performances. The method is conveniently implemented in a massive scale, continuously trainable retrieval engine, Monk.     

Structural and rheological properties of kappa (κ)-carrageenans covalently modified with cationic moieties

Cationized kappa-carrageenans containing 2-hydroxy-3-(trimethylammonium)propyl groups with various degrees of substitution (0.13–0.75) were synthesized by reaction of sulfated polysaccharides with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (QUAB 188) in alkaline solutions through the generation of the corresponding 2,3-epoxy reagent in situ. The structure of the modified algal polysaccharides was characterized without any further treatment or after methanolysis and/or enzymatic depolymerization, by means of spectroscopic tools (FT-IR, NMR, Mass spectrometry) and high-performance size exclusion chromatography (HPSEC). Significant differences in the rheological properties of these cationized kappa-carrageenans have been found depending on the DS values and the presence of KCl salt. Despite their lower molecular weights in comparison with native polysaccharides, cationized kappa-carrageenans with a DS of 0.75 exhibited high viscosity and gelling behaviors mediated by the high density of quaternary ammonium groups.     

Art Painting Diagnostic Before Restoration with Terahertz and Millimeter Waves

Art painting diagnostic is commonly performed using electromagnetic waves at wavelengths from terahertz to X-ray. These former techniques are essential in conservation and art history research, but they could be also very useful for restoring artwork. While most studies use time domain imaging technique, in this study, a painting has been investigated using both time domain imaging (TDI) and frequency-modulated continuous wave (FMCW) system in the millimeter frequency range. By applying these systems to a painting of the eighteenth century, we detect and analyze the structure of some defects. This study underlines the differences between FMCW and TDI. We present the advantages and disadvantages of each technique on a real artwork.