Cutting to the chase with warm-start contextual bandits

Knowledge and Information Systems - Multi-armed bandits achieve excellent long-term performance in practice and sublinear cumulative regret in theory. However, a real-world limitation of bandit...     

Carbon-Methanol Based Adsorption Heat Pumps: Identifying Accessible Parameter Space with Carbide-Derived Carbon Model Materials

In adsorption heat pumps, the properties of the porous adsorbent and the refrigerant determine the performance. Major parameters for this working pair are the total uptake of the adsorptive, its kinetics, and the heat transfer characteristics. In the technical application despite powdered adsorbents, thin consolidated layers of the adsorbent can be attractive and obtained by a binder-based approach but likely result in competing material properties. Thus, for a process optimization, the accessible parameter space and interdependencies have to be known and were deduced in this work for model porous carbons (carbide-derived carbons derived from TiC and ZrC) and methanol as well as the addition of different amounts of boron nitride, silver, and graphite as heat-conductive agents and the use of two binders.     

Calculating morphology development of polymer blends in extruders on the basis of results of boundary and finite element simulations using the sigma simulation software

Models have been developed for binary, incompatible polymer blends that can be used to estimate the morphology development that takes place in drops of the second component that are dispersely embedded in the matrix. The calculations are based on the results of flow simulations using the boundary element (BEM) and finite element (FEM) methods and, more particularly, on an analysis of the stresses that act on fluid particles over their trajectories as a function of the residence time. The models formulated are converted into algorithms, which can then be implemented in the SIGMA simulation software for designing and simulating the process behavior in tightly intermeshing co‐rotating twin‐screw extruders. In this way, it is possible to estimate the morphology development that takes place in incompatible polymer systems by describing the mean drop size and the drop size distribution as a function of the material properties, the geometry of the barrel and the screw, and the process parameters.     

Towards Keratan Sulfate – Chemoenzymatic Cascade Synthesis of Sulfated N‐Acetyllactosamine (LacNAc) Glycan Oligomers

We report on a novel chemoenzymatic cascade for the synthesis of sulfated N‐acetyllactosamine [(3Galβ1,4GlcNAcβ1,)_n, LacNAc] oligomer structures. Starting from a linker modified GlcNAc substrate di‐ and trisaccharides were first synthesized by sequential use of human β4‐galactosyltransferase‐1 (β4GalT‐1) and β3‐N‐acetylglucosaminyltransferase from Helicobacter pylori (β3GlcNAcT). Subsequent regioselective chemical sulfation rendered the C‐6 mono‐, di‐, and tri‐O‐sulfated products in good yields. Further enzymatic elongation by β4GalT‐1 and β3GlcNAcT in a sequential mode yielded 6‐O‐sulfated LacNAc oligomers up to hexasaccharide length with variable degrees of sulfation. These carbohydrate structures mimic the sulfation pattern found in keratan sulfate and are potential ligands for different classes of glycan binding proteins.

     

Development and Validation of a Novel 11-Gene Prognostic Model for Serous Ovarian Carcinomas Based on Lipid Metabolism Expression Profile

(1) Background: Biomarkers might play a significant role in predicting the clinical outcomes of patients with ovarian cancer. By analyzing lipid metabolism genes, future perspectives may be uncovered; (2) Methods: RNA-seq data for serous ovarian cancer were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases. The non-negative matrix factorization package in programming language R was used to classify molecular subtypes of lipid metabolism genes and the limma package in R was performed for functional enrichment analysis. Through lasso regression, we constructed a multi-gene prognosis model; (3) Results: Two molecular subtypes were obtained and an 11-gene signature was constructed (PI3, RGS, ADORA3, CH25H, CCDC80, PTGER3, MATK, KLRB1, CCL19, CXCL9 and CXCL10). Our prognostic model shows a good independent prognostic ability in ovarian cancer. In a nomogram, the predictive efficiency was notably superior to that of traditional clinical features. Related to known models in ovarian cancer with a comparable amount of genes, ours has the highest concordance index; (4) Conclusions: We propose an 11-gene signature prognosis prediction model based on lipid metabolism genes in serous ovarian cancer.     

Simulative Approach for Linking Electrode and Electrolyte Properties to Supercapacitor Performance

Supercapacitors as energy storage devices show distinct advantages like high power density and high cycle stability. While in current applications, mainly the high power density is leveraged, future non‐mobile storage devices could also benefit from the robustness and materials employed, while lower charging/discharging time constants are acceptable. In this study, a simulative approach is employed to investigate the complex interplay of mass transfer, electric losses, double layer capacitance for different electrode thicknesses, electrode and electrolyte conductivities as well as charging/discharging time constants. Within the simulation cyclic voltammetry, galvanostatic cycling as also electrochemical impedance spectroscopy experiment could be realized, showing the dependency of achievable maximum capacitance and voltage efficiency on various properties.     

Glassomer—Processing Fused Silica Glass Like a Polymer

Fused silica glass is one of the most important high‐performance materials for scientific research, industry, and society. However due to its high chemical and thermal resistance as well as high hardness, fused silica glass is notoriously difficult to structure. This work introduces Glassomer, a solid nanocomposite, which can be structured using polymer molding and subtractive technologies at submicrometer resolution. After polymer processing Glassomer is turned into optical grade fused silica glass during a final heat treatment. The resulting glass has the same optical transparency as commercial fused silica and a smooth surface with a roughness of a few nanometers. This work makes high‐performance fused silica glass components accessible to high‐throughput fabrication technologies and will enable numerous optical, photonic and medical applications in science and industry.     

Walking dynamics are symmetric (enough)

Many biological phenomena such as locomotion, circadian cycles and breathing are rhythmic in nature and can be modelled as rhythmic dynamical systems. Dynamical systems modelling often involves neglecting certain characteristics of a physical system as a modelling convenience. For example, human locomotion is frequently treated as symmetric about the sagittal plane. In this work, we test this assumption by examining human walking dynamics around the steady state (limit-cycle). Here, we adapt statistical cross-validation in order to examine whether there are statistically significant asymmetries and, even if so, test the consequences of assuming bilateral symmetry anyway. Indeed, we identify significant asymmetries in the dynamics of human walking, but nevertheless show that ignoring these asymmetries results in a more consistent and predictive model. In general, neglecting evident characteristics of a system can be more than a modelling convenience—it can produce a better model.