Investigating the impact of regiochemistry in ester functionalized polyfurans

In this study, the impact of ester side group regiochemistry on electronic and conformational properties of regioregular polyfurans was explored. A derivative with alternating head-to-head and tail-to-tail orientation of the side groups was synthesized and compared with its head-to-tail analogue, and these were benchmarked against the related regioregular poly(3-hexylfurans). The study revealed that alkyl ester side groups in a head-to-head orientation will create significant steric strain as compared with linear alkyl chains with identical regiochemistry. Though the head-to-head ester side groups lead to twisting along the polymer backbone, they also produce a protective effect against photodegradation in comparison with a poly(3-hexylfuran). Altogether, the work highlights how side groups can impact conformational properties and stability of polyfurans.     

A novel coupled system of non-local integro-differential equations modelling Young’s modulus evolution,nutrients’ supply and consumption during bone fracture healing

During fracture healing, a series of complex coupled biological and mechanical phenomena occurs. They include: (i) growth and remodelling of bone, whose Young’s modulus varies in space and time; (ii) nutrients’ diffusion and consumption by living cells. In this paper, we newly propose to model these evolution phenomena. The considered features include: (i) a new constitutive equation for growth simulation involving the number of sensor cells; (ii) an improved equation for nutrient concentration accounting for the switch between Michaelis–Menten kinetics and linear consumption regime; (iii) a new constitutive equation for Young’s modulus evolution accounting for its dependence on nutrient concentration and variable number of active cells. The effectiveness of the model and its predictive capability are qualitatively verified by numerical simulations (using COMSOL) describing the healing of bone in the presence of damaged tissue between fractured parts.     

On the pointwise limits of sequences of Świątkowski functions

The characterization of the pointwise limits of the sequences of ?wi?tkowski functions is given. Modifications of ?wi?tkowski property with respect to different topologies finer than the Euclidean topology are discussed.     

Analyzing thermoregulation processes in early school-age girls and boys through thermography

Journal of Thermal Analysis and Calorimetry - The research assessed thermoregulation processes in early school-age children. Thermal maps of the subjects’ bodies were compared before and...     

De novo prediction of the elemental composition of peptides and proteins based on a single mass

Identification of peptides and proteins is a common task in mass spectrometry–based proteomics but often fails to deliver a comprehensive list of identifications. Downstream analysis, quantitative or qualitative, depends on the outcome of this process. Despite continuous improvement of computational methods, a large fraction of the screened peptides and/or proteins remains unidentified. We introduce here pacMASS, a method that de novo predicts the elemental composition of peptides and small proteins based on a single accurate mass, ie, the observed monoisotopic or average mass. This novel approach returns in a fast and memory efficient manner a limited number of elemental compositions per queried peptide or protein.     

Methodological inaccuracies in clinical aortic valve severity assessment: insights from computational fluid dynamic modeling of CT-derived aortic valve anatomy

Aortic stenosis is the most common valvular heart disease. Assessing the contribution of the valve as a portion to total ventricular load is essential for the aging population. A CT scan for one patient was used to create one in vivo tricuspid aortic valve geometry and assessed with computational fluid dynamics (CFD). CFD simulated the pressure, velocity, and flow rate, which were used to assess the Gorlin formula and continuity equation, current clinical diagnostic standards. The results demonstrate an underestimation of the anatomic orifice area (AOA) by Gorlin formula and overestimation of AOA by the continuity equation, using peak velocities, as would be measured clinically by Doppler echocardiography. As a result, we suggest that the Gorlin formula is unable to achieve the intended estimation of AOA and largely underestimates AOA at the critical low-flow states present in heart failure. The disparity in the use of echocardiography with the continuity equation is due to the variation in velocity profile between the outflow tract and the valve orifice. Comparison of time-averaged orifice areas by Gorlin and continuity with instantaneous orifice areas by planimetry can mask the errors of these methods, which is a result of the assumption that the blood flow is inviscid.     

Feasibility study of the standing accretion shock instability experiment at the National Ignition Facility

The primary hydrodynamic flow feature of early explosion phases of a core-collapse supernova is a spherical shock. This shock is born deep in the central regions of the collapsing stellar core, stalls shortly afterward, and in case of a successful explosion is revived and becomes the supernova shock. The revival process involves a standing accretion shock instability, SASI. This shock instability is considered the key processes aiding the core-collapse supernova (ccSN) explosion.The aim of our study is to identify feasible conditions and parameters for an experimental system that is able to capture the essential characteristics of SASI. We use semi-analytic methods and high-resolution hydrodynamic simulations in multidimensions to investigate a possible experimental design on the National Ignition Facility. The experimental configuration involves a steady, spherical shock. We explore a viable region of parameters and obtain limits on the shocked flow geometry. We study the stability properties of the shock and its post-shock region.We compare properties of the experimental design and the ccSN environment. The obtained model experimental flow field closely resembles converging nozzle flow. The post-shock region, in contrast to the supernova setting, is found to be stably stratified and stable against to perturbations upstream of the shock. We conclude that it is not possible to capture the characteristics of the ccSN SASI for the converging shocked flow configuration considered here. However, such configuration offers a very stable setting for precision studies of dense, high-temperature plasmas requiring finely-controlled conditions and long lifetimes.