Development of Copper Selenide Quantum Dots-Based Therapeutic Drug Monitoring Biosensors for Toremifene - A Breast Cancer Drug

Magister Scientiae - MSc (Chemistry)With rising knowledge of the effects on plasma concentration caused by allelic variations in the cytochrome P450 genes and other metabolic factors such as drug-drug or drug-food interactions, more attention is paid to the possibility of therapeutic drug monitoring (TDM). Thus, there is a rising demand for quick, low-cost and efficient equipment for drug targeting. For such devices, electrochemical biosensing techniques serve as a promising alternative. Toremifene is the chlorinated analogue of tamoxifen and is used for adjuvant antiestrogenic treatment for breast cancer and could serve as a candidate for TDM treatments. In this work, a proof of concept enzymatic electrochemical biosensor is developed for the detection of toremifene in aqueous solution. The biosensor uses water-soluble 6-mercaptopropinoic acid capped copper selenide quantum dots (6MHACuSe QDs) conjugated to a cysteamine selfassembled monolayer on a gold electrode. The 6MHACuSe QDs where further conjugated with CYP2C9 enzyme, which has shown to have a major part in the hydroxylation of toremifene (TOR) to form 4-hydroxytoremifene (4OH-TOR). The 6MHACuSe QDs where synthesized using a facile and rapid aqueous route. Results from synthesis of 3-mercaptiorproionic acid (3MPA) and mercaptosuccinic acid (MSA) capped copper selenide QDs, are also presented in the study and compared to the results of the 6MHA capped copper selenide QDs. X-ray diffraction analysis (XRD) confirmed formation of copper selenide species of nonstoichiometric form Cu2-xSe (for the 6MHA and 3MPA capped CuSe QDs) and ?-CuSe stoichiometric form (for the MSA capped CuSe QDs)

Resonance and cancellation phenomena in two-span continuous beams and its application to railway bridges

The objective of this study is to evaluate the vibratory response of two-span continuous beams subjected to moving loads and, in particular, to investigate the maximum resonance and cancellation of resonance phenomena. The main practical interest is the evaluation of the maximum acceleration response in railway bridges, which is one of the most demanding Serviceability Limit States for traffic safety according to current regulations. Two-span continuous bridges, in their simplest version (i.e. uniform identical spans), present antisymmetric and symmetric modes with closely spaced natural frequencies, leading to a more involved dynamic behaviour than that of simply-supported bridges. First, the free vibration response of a Bernoulli-Euler two-span beam after the passage of a single load at constant speed is formulated analytically, and non-dimensional speeds leading to cancellation or maximum response in free vibration are obtained for each mode. Then, these conditions are equated to resonant speeds induced by equidistant load series, and span length-to-characteristic distance ratios causing cancelled out resonances, or remarkably prominent ones, are obtained. Based on the previous derivations, a methodology for detecting which could be the most aggressive trains for a particular structure based on pure geometrical considerations is discussed. Finally, the applicability of the theoretical derivations is shown through the numerical analysis of two real bridges belonging to the Swedish railway network

Free vibration of viscoelastically supported beam bridges under moving loads: Closed-form formula for maximum resonant response

[EN] In this paper, a closed-form approximate formula for estimating the maximum resonant response of beam bridges on viscoelastic supports (VS) under moving loads is proposed. The methodology is based on the discrete approximation of the fundamental vertical mode of a non-proportionally damped Bernoulli-Euler beam, which allows the derivation of closed-form expressions for the fundamental modal characteristics and maximum amplitude of free vibration at the mid-span of VS beams. Finally, an approximate formula to estimate maximum resonant acceleration of VS beams under passage of articulated trains has been proposed. Verification studies prove that the approximate closed-form formula estimates the resonant peaks with good accuracy and is a useful tool for preliminary assessment of railway beam bridges considering the effect of soil-structure interaction at resonance. In combination with the use of full train signatures through the Residual Influence Line (LIR) method, the proposed solution yields good results also in the lower range of speeds, where resonant sub-harmonics are more intensely reduced by damping.This research was partly sponsored by the Swedish Research Council FORMAS and has also received funding from the Shift2Rail Joint Undertaking under the European Union's Horizon 2020 research and innovation program under grant agreement No 826255 which are gratefully acknowledged.Zangeneh, A.; Museros Romero, P.; Pacoste, C.; Karoumi, R. (2021). Free vibration of viscoelastically supported beam bridges under moving loads: Closed-form formula for maximum resonant response. Engineering Structures. 244:1-11. https://doi.org/10.1016/j.engstruct.2021.112759S11124

Experimental and Numerical Dynamic Properties of Two Timber Footbridges Including Seasonal Efects

This paper deals with experimental and numerical dynamic analyses of two timber footbridges. Both bridges have a span of 35 m and consist of a timber deck supported by two timber arches. The main purpose is to investigate if the dynamic properties of the bridges are season dependent. To this end, experimental tests are performed during a cold day in winter and a warm day in spring in Sweden. The frst bending and transverse mode frequencies increase 22% and 44%, respectively, due to temperature efects in the case of Vega Bridge. In the case of Hägernäs bridge, the corresponding values are 5% and 26%. For both bridges, the measured damping coefcients are similar in winter and spring. However, the damping coeffcients for the frst bending and transverse modes are diferent for both footbridges: about 1% for the Hägernäs bridge and 3% for the Vega bridge. Finite-element models are also implemented. Both numerical and experimental results show good correspondence. From the analyses performed, it is concluded that the connections between the diferent components of the bridges have a signifcant infuence on the dynamic properties. In addition, the variation of the stifness for the asphalt layer can explain the diferences found in the natural frequencies between spring and winter. However, due to the uncertainties in the modelling of the asphalt layer, this conclusion must be taken with caution

A kinematically exact finite element formulation of planar elastic-plastic frames

A finite element formulation of finite deformation static analysis of plane elastic-plastic frames subjected to static loads is presented, in which the only function to be interpolated is the rotation of the centroid axis of the beam. One of the advantages of such a formulation is that the problem of the field-consistency does not arise. Exact non-linear kinematic relationships of the finite-strain beam theory are used, which assume the Bernoulli hypothesis of plane cross-sections. Finite displacements and rotations as well as finite extensional and bending strains are accounted for. The effects of shear strains and non-conservative loads are at present neglected, yet they can simply be incorporated in the formulation. Because the potential energy of internal forces does not exist with elastic-plastic material, the principle of virtual work is introduced as the basis of the finite element formulation. A generalized principle of virtual work is proposed in which the displacements, rotation, extensional and bending strains, and the Lagrangian multipliers are independent variables. By exploiting the special structure of the equations of the problem, the displacements, the strains and the multipliers are eliminated from the generalized principle of virtual work. A novel principle is obtained in which the rotation becomes the only function to be approximated in its finite element implementation. It is shown that (N-1)-point numerical integration must be employed in conjunction with N-node interpolation polynomials for the rotation, and the Lobatto rule is recommended. Regarding the integration over the cross-section, it is demonstrated by numerical examples that, due to discontinuous integrands, no integration order defined as `computationally efficient yet accurate enough' could be suggested. The theoretical findings and a nice performance of the derived finite elements are illustrated by numerical examples

Polar decomposition based corotational framework for triangular shell elements with distributed loads

A polar decomposition based corotational formulation for deriving geometrically nonlinear triangular shell elements is proposed. This formulation is novel in two aspects. (1) Original formulas for the projector operator and its variation are presented, leading to simple algorithms for the computation of the nodal residual vector and of the consistent tangent stiffness tensor. (2) For the first time in the context of a corotational kinematic description, a rigorous treatment of distributed dead and follower loads is performed, thoroughly accounting for the various contributions entailed in the residual vector and in the tangent stiffness. Numerical simulations of popular benchmark problems are reported, showing the effectiveness of the proposed approach. An accessible and adaptable MATLAB toolkit implementing the present formulation is provided as supplementary material

3DED/MicroED on iron(III)acetyl acetonate

<p><span>3DED/MicroED datasets of iron(III)acetyl acetonate collected on Titan Krios cryo-Transmission Electron Microscope (cryo-TEM) from ThermoFisher Scientific, which operates at 300 kV and is equipped with a Ceta-D CMOS detector.</span></p&gt