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The local stresses near the web-flange connection usually represent one of the most decisive criteria for the fatigue design of steel crane runway girders, particularly because every crane wheel induces an individual stress cycle and fatigue failure can potentially occur at any position of the girder’s length. This paper presents a crane runway girder made of steel that has been retrofitted in the past to reduce the local bending stresses in the web, because of the installation of a new, heavier crane. This was done by additional longitudinal stiffeners to form a boxed upper flange. The local vertical stresses in the girder’s web are investigated numerically and experimentally and the influence of the subsequently attached reinforcement plates, forming a boxed upper flange, is studied. Traditionally, it is state of the art to neglect any local bending stresses in the web after retrofitting the upper flange area to get a local box section. The results presented in this paper indicate that the additional local bending stresses within the upper flange box section can be significant and should not be neglected for fatigue design. Therefore, a new design concept for the calculation of the local bending stresses in webs of retrofitted crane runway girders with new boxed upper flange is presented.

Neutrophil extracellular trap (NET) formation is a powerful instrument to fight pathogens, but may induce collateral damage in the affected tissues. Besides pathogen-derived factors, immune complexes are potent inducers of NET formation. Neutrophils express IgA and IgG specific Fc receptors (FcRs) and therefore respond to complexed IgA and IgG. Especially in the context of autoimmune diseases, IgA and IgG immune complexes have been shown to trigger NET formation, a process that putatively contributes to disease severity. However, it is of question if both antibody classes stimulate neutrophils to the same extent. In this study, we compared the capability of IgA and IgG complexes formed by heat aggregation to induce NET formation. While stimulation of neutrophils with IgA complexes robustly induced NET formation, complexed IgG only marginally increased the amount of NETs compared to the unstimulated control. Mixing IgA with IgG before heat aggregation did not increase the effect of complexed IgA on neutrophils. By contrast, the presence of IgG complexes seemed to disturb neutrophil stimulation by IgA complexes. The capacity of complexed IgG to induce NET formation could not be increased by the addition of autologous serum or the removal of terminal sialic acid in the Fc glycan. Together, our data show that IgA is a much more potent inducer of NET formation than IgG. IgA may thus be the main driving force in (auto)immune complex-mediated NET formation.

In the field of molecular communication, molecules or other particles in the nanoscale are used to transmit information. This rather new communication paradigm has a large application potential, ranging from medicine to industrial systems. As testbeds are essential for evaluating the capabilities of this new form of communication, we improve an existing water-based testbed to achieve parallel data transmission within one communication channel in this work. To this end, two different information carriers, superparamagnetic iron oxide nanoparticles and fluorescent particles, are used to simultaneously transmit independent data streams. A detection system for fluorescent particles was specifically developed for the fluid molecular communication testbed. Using parallel data transmission in the modified testbed the channel capacity was nearly doubled in comparison to a transmission using only a single type of information particles.

In the past decades, a wide variety of different superparamagnetic iron oxide nanoparticles (SPIONs) have been synthesized. Due to their unique properties, such as big surface-to-volume ratio, superparamagnetism and comparatively low toxicity, they are principally well suited for many different technical and biomedical applications. Meanwhile, there are a numerous synthesis methods for SPIONs, but high requirements for biocompatibility have so far delayed a successful translation into the clinic. Moreover, depending on the planned application, such as for imaging, magnetic drug targeting, hyperthermia or for hybrid materials intended for regenerative medicine, specific physicochemical and biological properties are inevitable. Since a summary of all existing SPION systems, their properties and application is far too extensive, this review reports on selected methods for SPION synthesis, their biocompatibility and biomedical applications.

A major challenge in myocardial infarction (MI)-related heart failure treatment using microRNA is the efficient and sustainable delivery of miRNAs into myocardium to achieve functional improvement through stimulation of intrinsic myocardial restoration. In this study, we established an in vivo delivery system using polymeric nanoparticles to carry miRNA (miNPs) for localized delivery within a shear-thinning injectable hydrogel. The miNPs triggered proliferation of human embryonic stem cell-derived cardiomyocytes and endothelial cells (hESC-CMs and hESC-ECs) and promoted angiogenesis in hypoxic conditions, showing significantly lower cytotoxicity than Lipofectamine. Furthermore, one injected dose of hydrogel/miNP in MI rats demonstrated significantly improved cardiac functions: increased ejection fraction from 45% to 64%, reduced scar size from 20% to 10%, and doubled capillary density in the border zone compared to the control group at 4 weeks. As such, our results indicate that this injectable hydrogel/miNP composite can deliver miRNA to restore injured myocardium efficiently and safely.

The paper presents the detailed test setup and results of a test series on bolted single steel angles in compression with varying end support conditions and slenderness ratios. For all tests FEM-calculations were done, which are also presented. In total 27 specimens with one-bolt and two-bolt connections with and without preload are tested. Three different boundary conditions on both ends are investigated: Boundary condition 1 (BC1) is a clamped support. BC2 is a knife edge support that allows only for rotations about the axis parallel to the connected leg. BC3 is a fully hinged support. In addition to the results of the member tests, imperfection measurements and results of material tests are presented in order to carry out the FEM-calculations and to allow for comparison with current design standards.

According to the World Health Organization, cancer is the second most important cause of death in Europe. Due to its manifold manifestations, it is not possible to treat all patients according to a uniform scheme. However, all solid tumors have one thing in common: independent of the tumor’s molecular subgroup and the treatment protocol, the immune status of the tumor, especially the amount of tumor infiltrating lymphocytes (TILs), is important for the patient’s clinical outcome – the higher the number of TILs, the better the outcome. For this reason it seems desirable to increase the number of TILs. One way to accumulate T cells in the tumor area is to make them magnetizable and attract them with an external magnetic field. Magnetization can be achieved by superparamagnetic iron oxide nanoparticles (SPIONs) which can be bound to the cells’ surface or internalized into the cells. For this study, SPIONs with different coatings were synthesized and incubated with immortalized mouse T lymphocytes. SPIONs only stabilized with lauric acid (LA) coated in situ or afterwards showed high toxicity. Addition of an albumin layer increased the biocompatibility but reduced cellular uptake. To increase the cellular uptake the albumin coated particles were aminated, leading to both higher uptake and toxicity, dependent on the degree of amination. In the presence of an externally applied magnetic field, T cells loaded with selected types and amounts of SPIONs were guidable. With this promising pilot study we already can demonstrate that it is possible to attract SPION bearing T cells by an external magnet. To sum up, biocompatibility and uptake of SPIONs by T cells are opposing events. Thus, for the functionalization of T cells with SPIONs the balance between uptake and toxicity must be evaluated carefully.

Zusammenfassung Flüssigkeitsgefüllte Stahltanks werden häufig ohne aufwendige Zugverankerungen zu Betonfundamenten ausgeführt. Bei größeren Erdbebenereignissen kommt es daher zu einem lokalen, vertikalen Abheben des Behältermantels. Durch das mehrfache Abheben bei einem Erdbebenereignis, verbunden mit lokalen Wechselplastizierungen, besteht die Gefahr des Auftretens von Rissen und damit verbundenen Behälterundichtheiten durch Kurzzeitermüdung. Teil 1 des Beitrags fasst einleitend die Vorgehensweise nach Eurocode mit den zugehörigen Modellvorstellungen zusammen. Anschließend werden die Hauptergebnisse eines Forschungsprojektes zusammengefasst, das das realitätsnahe Beanspruchungsverhalten von abhebenden Tankbodenecken im Erdbebenfall mit beinhaltet hat, mit einer Beurteilung der mehrachsigen Ermüdungsbeanspruchung. Darauf aufbauend erfolgt in Teil 2 dieses Beitrags ein erster Vorschlag für ein Konzept einer baupraktischen Vorgehensweise, um den Sachverhalt der Kurzzeitermüdung bei unverankerten Stahltanks zutreffender nachzuweisen.

Zusammenfassung Flüssigkeitsgefüllte Stahltanks werden häufig ohne aufwendige Zugverankerungen zu Betonfundamenten ausgeführt. Bei größeren Erdbebenereignissen kommt es daher zu einem lokalen, vertikalen Abheben des Behältermantels. Durch das mehrfache Abheben bei einem Erdbebenereignis, besteht die Gefahr des Auftretens von Rissen und damit verbundenen Behälterundichtheiten durch Kurzzeitermüdung. Dieser Teil 2 des Beitrags beinhaltet einen ersten Vorschlag für ein Konzept einer baupraktischen Vorgehensweise, um den Sachverhalt der Kurzzeitermüdung bei der vorliegenden komplexen mehrachsigen Ermüdungsbeanspruchung von unverankerten Stahltanks zutreffender nachzuweisen.

Zusammenfassung Bei der statisch konstruktiven Auslegung der stählernen Druckschachtpanzerungen von Triebwasserwegen wird mitunter nicht die Innendruckbelastung maßgebend, sondern die Außendruckbelastung infolge Bergwasserdruck. Dieser führt im Revisionsfall bei entleerter Druckrohrleitung zu einer hohen Beulgefährdung, bedingt durch die ausgeführten großen Rohrschlankheiten. Die Bemessungsregeln in der Praxis basieren auf analytischen und empirischen Modellen, die im Wesentlichen bereits in den 1960er-Jahren entwickelt wurden. Dieser Beitrag fasst die Gesamtergebnisse eines Forschungsprojektes zusammen, dass das Ziel hatte durch nun verfügbare realitätsnahe numerische Modelle zusätzliche Effekte, wie verschiedene Imperfektionsformen, auftretende Längsdruckkräfte im Rohr infolge Reibschluss sowie die radiale Gebirgsnachgiebigkeit, mit zu berücksichtigen. Teil 1 beinhaltet die Ergebnisse für unversteifte Stahlrohre. Es werden einleitend die in der Praxis üblichen Bemessungsmodelle zur Ermittlung der kritischen Außendruckbelastung p0,cr erläutert und hinsichtlich ihrer Ergebnisse miteinander verglichen. Aus dem zusätzlichen Vergleich mit den numerischen Berechnungsergebnissen wird das zutreffendste Bemessungsmodell für die Praxis dargestellt und auch in Form von Bemessungsdiagrammen aufbereitet.

Zusammenfassung Bei der statisch konstruktiven Auslegung der stählernen Druckschachtpanzerungen von Triebwasserwegen wird mitunter nicht die Innendruckbelastung maßgebend, sondern die Außendruckbelastung infolge Bergwasserdruck. Dieser führt im Revisionsfall bei entleerter Druckrohrleitung zu einer hohen Beulgefährdung, bedingt durch die ausgeführten großen Rohrschlankheiten. Nachdem Teil 1 dieses Beitrages die praktische Bemessung unter Außendruck von unversteiften Stahlrohren behandelte, geht nun der Teil 2 auf den häufigeren Ausführungsfall der ringversteiften Stahlrohre ein. Einleitend wird wieder das in der Praxis übliche Bemessungsmodell dargestellt, mit globaler Betrachtung des Beulens des Ringes mit dazwischenliegendem Rohr sowie der isolierten Beulbetrachtung der Zylinderschale zwischen den Ringen. Danach werden die Ergebnisse einer umfangreichen numerischen Traglaststudie (FEA) für repräsentative Anwendungsbeispiele, mit zusätzlicher Variation des Ringabstandes, gezeigt. Der Ergebnisvergleich des aufnehmbaren Außendrucks pFEA mit der aktuellen Vorgehensweise deutet – trotz erheblichem Berechnungsaufwand – auf Defizite in der Treffsicherheit. Es wird deshalb ein einfacheres, neues Berechnungsmodell für ringversteifte Stahlrohre und die Hintergründe zu dessen Kalibrierung vorgestellt sowie auch die Treffsicherheit im Vergleich zur numerischen Traglastberechnung gezeigt.

Superparamagnetic iron oxide nanoparticles (SPIONs) feature distinct magnetic properties that make them useful and effective tools for various diagnostic, therapeutic and theranostic applications. In particular, their use in magnetic drug targeting (MDT) promises to be an effective approach for the treatment of various diseases such as cancer. At the cellular level, SPION uptake, along with SPION-mediated toxicity, represents the most important prerequisite for successful application. Thus, the present study determines SPION uptake, toxicity and biocompatibility in human head and neck tumor cell lines of the tongue, pharynx and salivary gland. Using magnetic susceptibility measurements, microscopy, atomic emission spectroscopy, flow cytometry, and plasma coagulation, we analyzed the magnetic properties, cellular uptake and biocompatibility of two different SPION types in the presence and absence of external magnetic fields. Incubation of cells with lauric acid and human serum albumin-coated nanoparticles (SPIONLA-HSA) resulted in substantial particle uptake with low cytotoxicity. In contrast, uptake of lauric acid-coated nanoparticles (SPIONLA) was substantially increased but accompanied by higher toxicity. The presence of an external magnetic field significantly increased cellular uptake of both particles, although cytotoxicity was not significantly increased in any of the cell lines. SPIONs coated with lauric acid and/or human serum albumin show different patterns of uptake and toxicity in response to an external magnetic field. Consequently, the results indicate the potential use of SPIONs as vehicles for MDT in head and neck cancer.

Testbeds are required to assess concepts and devices in the context of molecular communication. These allow the observation of real-life phenomena in a controlled environment and therefore present the basis of future work. A testbed using superparamagnetic iron oxide nanoparticles (SPIONs) as information carriers was constructed with regard to this context and requires a sensitive receiver for the detection of SPIONs.This paper focusses on the comparison between a newly presented device (inductance sensor), a previously constructed SPION sensor (resonance bridge), and a commercial susceptometer as reference. The new inductance sensor is intended to improve on a low sensitivity achieved with the previous device and restrictions with respect to sample rate and measurement aperture encountered with the susceptometer. The signal-to-noise ratio (SNR) for each device is assessed at a variety of SPION concentrations. Furthermore, the sensors bit error rates (BER) for a random bit sequence are determined.The results show the device based on an inductance sensor to be the most promising for further investigation as values both for BER and SNR exceed those of the resonance bridge while providing a su?ciently high sample rate. On average the SNR of the new device is 13 dB higher while the BER for the worst transmission scenario is 9% lower. The commercial susceptometer, although returning the highest SNR, lacks adaptability for the given use case.

Molecular communication in pipe networks is a novel technique for wireless data exchange. Simulating such networks accurately is difficult because of the complexity of fluid dynamics at centimeter scales, which existing molecular communication simulators do not model. The new simulator we present combines computational fluid dynamics simulation and particle movement predictions. It is optimized to be computationally efficient while offering a high degree of adaptability to complex fluid flows in larger pipe networks. We validate it by comparing the simulation with experimental results obtained in a real-world testbed.

Monomeric serum immunoglobulin A (IgA) can contribute to the development of various autoimmune diseases, but the regulation of serum IgA effector functions is not well defined. Here, we show that the two IgA subclasses (IgA1 and IgA2) differ in their effect on immune cells due to distinct binding and signaling properties. Whereas IgA2 acts pro-inflammatory on neutrophils and macrophages, IgA1 does not have pronounced effects. Moreover, IgA1 and IgA2 have different glycosylation profiles, with IgA1 possessing more sialic acid than IgA2. Removal of sialic acid increases the pro-inflammatory capacity of IgA1, making it comparable to IgA2. Of note, disease-specific autoantibodies in patients with rheumatoid arthritis display a shift toward the pro-inflammatory IgA2 subclass, which is associated with higher disease activity. Taken together, these data demonstrate that IgA effector functions depend on subclass and glycosylation, and that disturbances in subclass balance are associated with autoimmune disease., Immunoglobulin A (IgA) has two subclasses, IgA1 and IgA2, but differential effects on inflammation are unclear. Here the authors show that IgA2, when compared with IgA1, has stronger pro-inflammatory functions associated with changed glycosylation and higher disease scores in patients with rheumatoid arthritis.

Testbeds are required to assess concepts and devices in the context of molecular communication. These allow the observation of real-life phenomena in a controlled environment and therefore present the basis of future work. A testbed using superparamagnetic iron oxide nanoparticles (SPIONs) as information carriers was constructed with regard to this context and requires a sensitive receiver for the detection of SPIONs.

Für die Berechnung von Verbundstützen sind in Eurocode 4 mehrere Bemessungsverfahren vorgesehen, die einleitend dargestellt werden. Die bisher in der Praxis üblichen vereinfachten Bemessungsverfahren werden durch ein allgemeines Verfahren ergänzt, das durch die jüngste Weiterentwicklung nicht-linearer FE-Berechnungsmethoden auch in der Ingenieurpraxis immer mehr Verbreitung findet. Für die in der Praxis meist verwendeten symmetrischen Querschnittsformen erfolgten umfangreiche Parameterstudien und ein Vergleich der Traglasten nach den einzelnen Bemessungsverfahren wird in diesem Beitrag zusammengefasst. Bei alleiniger zentrischer Druckbeanspruchung werden die beiden möglichen vereinfachten Bemessungsverfahren verglichen. Bei Druck und Biegung erfolgt ein Vergleich zwischen vereinfachtem und allgemeinem Berechnungsverfahren. Ergänzend werden für den sehr häufigen Fall der einachsigen Biegebeanspruchung die zutreffenden Knicknachweise dargestellt. Ziel dieses Beitrags ist, dem in der Praxis tätigen Ingenieur darzustellen, welches Bemessungsverfahren im einzelnen Anwendungsfall effizient und sinnvoll einsetzbar ist.

Knowledge of type and size of rotational restraints at the member's ends (provided by the adjacent structure) is crucial for the prediction of the compression member capacity of bolted angles. This was highlighted by means of experimental and numerical investigations in the past. Due to the eccentric connection on only one angle leg, additional bending moments are acting on the member, leading to a complex load carrying behaviour with flexural and/or lateral torsional buckling phenomena. Detailed analytical models for the estimation of appropriate spring stiffness values have been developed for several practical applications in buildings with two-bolt connections at both member's ends. The investigated connection details comprise a simply fixed gusset plate (e.g. as attachment to concrete walls), a joint to the flange of an I-shaped section and a joint to the web of an I-shaped section via a gusset plate. Based on that, a design model was developed for bolted angle members with rotational spring restraints at the member's ends and an eccentric compression loading N, in order to calculate the compression capacity NR. The thereby determined resistances NR,model are compared with the results of sophisticated 3D nonlinear finite element calculations NR,FE that consider the detailed joint configuration and the eccentric load introduction as well as equivalent geometric imperfections. It is shown that the resistances based on the proposed design procedure are slightly conservative compared to the real behaviour of the angle member. In addition, the large increase in capacity (compared to the simply supported reference case) is highlighted.

The design of crane runway girders is strongly affected by the local stresses due to wheel loads (mainly fatigue design, but also web buckling). A realistic approach of these local stresses, particularly the vertical direct stresses σ z at the web top, is very important for economic design. In this paper firstly a summary of formulae in literature and in relevant international design standards is given. These formulae are based on very limited tests in the past, which are also mentioned. In the main part of this paper new test results for local stresses in webs due to vertical wheel loads for crane runway girders with I-section and box section are given, also including different connections with the crane rails (with/without welds between rail and girder flange and cases with no rail). Centric loading was tested, but also eccentric loading with different eccentricities, leading to additional web bending out of plane. For all tests, accompanying comprehensive Finite Element analyses were conducted. These FE-models are also presented and their results are compared with the test results and with the predictions of design formulae, used in practice. Finally, additional numerical investigations are presented, dealing with the effects of different contact properties between rail and girder flange.

Nowadays trusses are often designed with I-sections only and no direct connection between the diagonal members and the chords. For the truss joints, gusset plates – welded to the chords – are used, which are slotted for the welding connection to the diagonal member. The main focus of the paper is the specific stability behaviour of such diagonal members in compression, leading to an interaction behaviour of member buckling out of plane and local buckling of the gusset plates. Within a comprehensive study a lot of different compression members and joint configurations were studied in detail, based on nonlinear numerical analyses. The results of four full scale tests on a lattice girder are presented in detail. In the four tests different I-sections with different gusset plate geometries were investigated. The most interesting fact is the comparison of the load carrying behaviour of the compressed diagonal members with increasing free length of the gusset plates. The member capacity of the tests is compared with the numerical results of a FE-model, considering the measured geometric imperfections and the measured material parameters. The overall load carrying behaviour of the truss in the test is analysed and compared with simplified models for global analyses, both for the load – deformation behaviour and for the relationship between load and member axial force. Finally a simple design model for the prediction of the ultimate capacity of the compression members is presented, which consists of a buckling verification based on the equivalent member with increased buckling length (section capacity near midspan is verified) and of an additional verification of the section capacity of the gusset plate. For the latter one the interaction of local and global buckling effect is important, leading to a simplified engineering model with all the relevant sources of geometric imperfections considered. It ends up with a check of the section capacity of the gusset plate, based on 2nd order internal forces (N&M). For slender gusset plates and also diagonal members with small slenderness, the section capacity of the gusset plates limits the load carrying capacity of the member and the buckling verification of the equivalent member may be on the unsafe side.

To avoid lateral torsional buckling in steel constructions, beams are often stiffened with discrete flexible intermediate supports (e.g. purlins in roof structures with bracings), which reduce lateral deformations of the flanges out of plane. Very often, these intermediate lateral supports can't be assumed as fully rigid and only restrain one of the flanges (i.e. no torsional restraint available), leading to a design situation that is only insufficiently reflected in EN 1993-1-1. Neither commonly used interaction formulae, derived on the basis of free single span members with fork end conditions and for members supported laterally and torsionally by intermediate rigid restraints, nor the simplified assessment method for beams with restraints in buildings (clause 6.3.2.4), based on a lateral buckling check of the compression flange, lead to an appropriate solution. In this paper, the results of an extensive numerical parametric study on beams with intermediate flexible lateral supports at the upper flange are presented. In the first part of the paper the focus is on the appropriate selection of the relevant buckling mode for the geometric imperfections, to obtain the minimum load carrying capacity within a numerical nonlinear calculation. As expected, a decrease of the spring stiffness always leads to a reduced elastic critical buckling load. Nevertheless, when assuming geometric imperfections based on the 1st buckling mode, this may lead to a higher ultimate load than for the system with rigid intermediate supports, when identical imperfection amplitudes are used. In the second part of the paper a first design proposal is presented, valid for different moment distributions and number and stiffness of intermediate supports.

For the prediction of the ultimate load of beams and columns, respectively susceptible to lateral torsional buckling and flexural buckling, numerical FEM-calculations including geometric imperfections and residual stresses (so-called “GMNIA analyses”), are becoming more commonly employed and recognized. In these analyses, the shape of the geometric imperfections is often based on the 1st buckling mode, seen as the worst case for these members. In this paper, the buckling behaviour of beams and columns with additional intermediate flexible supports is studied and illustrated, using additional spring elements with systematically varied stiffness. As expected, a decrease of the spring stiffness always leads to a reduced elastic critical buckling load. Nevertheless, when assuming geometric imperfections based on the 1st buckling mode, this may lead to a higher ultimate load than for the system with rigid intermediate supports, when identical imperfection amplitudes are used. These interesting results are presented and analyzed for two simple cases, in order to clearly show the main effects. These cases are: 1.) Columns under compression with additional flexible support at midspan; 2.) Beams under bending with additional flexible supports of the compressed flange only. For the latter case, a parametric study was performed, varying the number of intermediate supports and stiffness of the lateral supports.