Unique determination of a single crack in a uniform simply supported beam in bending vibration

In this paper we consider one of the basic inverse problems in damage detection based on natural frequency data, namely the identification of a single open crack in a uniform simply supported beam from measurement of the first and the second natural frequency. It is commonly accepted in the literature that the knowledge of this set of spectral data allows for the unique determination of the severity and the position (up to symmetry) of the damage. However, in spite of the fact that many numerical evidences are in support of this property, the result is rigorously proved only when the severity of the crack is small. In this paper we definitely show, by means of an original constructive method, that the above result holds true for any level of crack severity. (C) 2016 Elsevier Ltd. All rights reserved

Modulation of the equilibrative nucleoside transporter by inhibitors of DNA synthesis.

Expression of the equilibrative, S-(p-nitrobenzyl)-6-thioinosine (NBMPR)-sensitive nucleoside transporter (es), a component of the nucleoside salvage pathway, was measured during unperturbed growth and following exposure to various antimetabolites at growth-inhibitory concentrations. The probe 5-(SAENTA-x8)-fluorescein is a highly modified form of adenosine incorporating a fluorescein molecule. It binds. with high affinity and specificity to the (es) nucleoside transporter at a 1:1 stoichiometry, allowing reliable estimates of es expression by flow cytometry. Using a dual labelling technique which combined the vital DNA dye Hoechst-33342 and 5-(SAENTA-x8)-fluorescein, we found that surface expression of es approximately doubled between G1 and G2 + M phases of the cell cycle. To address the question of whether es expression could be modulated in cells exposed to drugs which inhibit de novo synthesis of nucleotides, cells were exposed to antimetabolite drugs having different modes of action. Hydroxyurea and 5-fluorouracil (5-FU), which inhibit the de novo synthesis of DNA precursors, produced increases in the expression of es. In contrast, cytosine arabinoside (ara-C) and aphidicolin, which directly inhibit DNA synthesis, produced no significant increase in es expression. Thymidine (TdR), which is an allosteric inhibitor of ribonucleotide reductase that depletes dATP, dCTP and dGTP pools while repleting the dTTP pool, had no significant effect on es expression. These data suggest that surface expression of the es nucleoside transporter is regulated by a mechanism which is sensitive to the supply of deoxynucleotides. Because 5-FU (which specifically depletes dTTP pools) causes a large increase in expression whereas TdR (which depletes all precursors except dTTP) does not, this mechanism might be particularly sensitive to dTTP pools

Explicit Determination of Pinned-Pinned Beams with a Finite Number of Given Buckling Loads

We present an analytical procedure for the exact, explicit construction of Euler-Bernoulli beams with given values of the first N buckling loads. The result is valid for pinned-pinned (P-P) end conditions and for beams with regular bending stiffness. The analysis is based on a reduction of the buckling problem to an eigenvalue problem for a vibrating string, and uses recent results on the exact construction of Sturm-Liouville operators with prescribed natural frequencies

Structural and magnetic dynamics of a laser induced phase transition in FeRh

We use time-resolved x-ray diffraction and magnetic optical Kerr effect to study the laser induced antiferromagnetic to ferromagnetic phase transition in FeRh. The structural response is given by the nucleation of independent ferromagnetic domains (\tau_1 ~ 30ps). This is significantly faster than the magnetic response (\tau_2 ~ 60ps) given by the subsequent domain realignment. X-ray diffraction shows that the two phases co-exist on short time-scales and that the phase transition is limited by the speed of sound. A nucleation model describing both the structural and magnetic dynamics is presented.Comment: 5 pages, 3 figures - changed to reflect version accepted for PR

Spontaneous pneumothorax and pneumomediastinum as a rare complication of COVID-19 pneumonia: Report of 6 cases

Spontaneous pneumothorax (SPT) and pneumomediastinum (SPM) have been reported as uncommon complications of coronavirus disease (COVID-19) pneumonia. The exact incidence and risk factors are still unrecognized. We report 6 nonventilated, COVID-19 pneumonia cases with SPT and SPM and their outcomes. The major risk factors for development of SPT and SPM in our patients were male gender, advance age, and pre-existing lung disease. These complications may occur in the absence of mechanical ventilation and associated with increasing morbidity (chest tube insertion, sepsis, hospital admission) and mortality. SPT and SPM should be considered as a potential predictive factor for adverse outcome and probable cause of unexplained deterioration of clinical condition in COVID-19 pneumonia. © 2021 The Author

Plasma pharmacokinetics after combined therapy of gemcitabine and oral S-1 for unresectable pancreatic cancer

<p>Abstract</p> <p>Background</p> <p>The combination of gemcitabine (GEM) and S-1, an oral 5-fluorouracil (5-FU) derivative, has been shown to be a promising regimen for patients with unresectable pancreatic cancer.</p> <p>Methods</p> <p>Six patients with advanced pancreatic cancer were enrolled in this pharmacokinetics (PK) study. These patients were treated by oral administration of S-1 30 mg/m²twice daily for 28 consecutive days, followed by a 14-day rest period and intravenous administration of GEM 800 mg/m²on days 1, 15 and 29 of each course. The PK parameters of GEM and/or 5-FU after GEM single-administration, S-1 single-administration, and co-administration of GEM with pre-administration of S-1 at 2-h intervals were analyzed.</p> <p>Results</p> <p>The maximum concentration (Cmax), the area under the curve from the drug administration to the infinite time (AUCinf), and the elimination half-life (T1/2) of GEM were not significantly different between GEM administration with and without S-1. The Cmax, AUCinf, T1/2, and the time required to reach Cmax (Tmax) were not significantly different between S-1 administration with and without GEM.</p> <p>Conclusion</p> <p>There were no interactions between GEM and S-1 regarding plasma PK of GEM and 5-FU.</p

Quantitative TEM imaging of the magnetostructural and phase transitions in FeRh thin film systems

Equi-atomic FeRh is a very interesting material as it undergoes a magnetostructural transition from an antiferromagnetic (AF) to a ferromagnetic (FM) phase between 75-105 °C. Its ability to present phase co-existence separated by domain walls (DWs) above room temperature provides immense potential for exploitation of their DW motion in spintronic devices. To be able to effectively control the DWs associated with AF/FM coexistence in FeRh thin films we must fully understand the magnetostructural transition and thermomagnetic behaviour of DWs at a localised scale. Here we present a transmission electron microscopy investigation of the transition in planar FeRh thin-film samples by combining differential phase contrast (DPC) magnetic imaging with in situ heating. We perform quantitative measurements from individual DWs as a function of temperature, showing that FeRh on NiAl exhibits thermomagnetic behaviour consistent with the transition from AF to FM. DPC imaging of an FeRh sample with HF-etched substrate reveals a state of AF/FM co-existence and shows the transition from AF to FM regions proceeds via nucleation of small vortex structures, which then grow by combining with newly nucleated vortex states into larger complex magnetic domains, until it is in a fully-FM state

Substrate Induced Strain Field in FeRh Epilayers Grown on Single Crystal MgO (001) Substrates

Equi-atomic FeRh is highly unusual in that it undergoes a first order meta-magnetic phase transition from an antiferromagnet to a ferromagnet above room temperature (Tr ≈ 370 K). This behavior opens new possibilities for creating multifunctional magnetic and spintronic devices which can utilise both thermal and applied field energy to change state and functionalise composites. A key requirement in realising multifunctional devices is the need to understand and control the properties of FeRh in the extreme thin film limit (tFeRh < 10 nm) where interfaces are crucial. Here we determine the properties of FeRh films in the thickness range 2.5–10 nm grown directly on MgO substrates. Our magnetometry and structural measurements show that a perpendicular strain field exists in these thin films which results in an increase in the phase transition temperature as thickness is reduced. Modelling using a spin dynamics approach supports the experimental observations demonstrating the critical role of the atomic layers close to the MgO interface