@misc{BarthWeingartenOgden2021, author = {Barth-Weingarten, Dagmar and Ogden, Richard}, title = {"Chunking" spoken language}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Philosophische Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Philosophische Reihe}, publisher = {Universit{\"a}t Potsdam}, address = {Potsdam}, issn = {1866-8380}, doi = {10.25932/publishup-53625}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-536259}, pages = {531 -- 548}, year = {2021}, abstract = {In this introductory paper to the special issue on "Weak cesuras in talk-in-interaction", we aim to guide the reader into current work on the "chunking" of naturally occurring talk. It is conducted in the methodological frameworks of Conversation Analysis and Interactional Linguistics - two approaches that consider the interactional aspect of humans talking with each other to be a crucial starting point for its analysis. In doing so, we will (1) lay out the background of this special issue (what is problematic about "chunking" talk-in-interaction, the characteristics of the methodological approach chosen by the contributors, the cesura model), (2) highlight what can be gained from such a revised understanding of "chunking" in talk-in-interaction by referring to previous work with this model as well as the findings of the contributions to this special issue, and (3) indicate further directions such work could take starting from papers in this special issue. We hope to induce a fruitful exchange on the phenomena discussed, across methodological divides.}, language = {en} } @article{BarthWeingartenOgden2021, author = {Barth-Weingarten, Dagmar and Ogden, Richard}, title = {"Chunking" spoken language}, series = {Open linguistics}, volume = {7}, journal = {Open linguistics}, number = {1}, publisher = {De Gruyter}, address = {Berlin}, issn = {2300-9969}, doi = {10.1515/opli-2020-0173}, pages = {531 -- 548}, year = {2021}, abstract = {In this introductory paper to the special issue on "Weak cesuras in talk-in-interaction", we aim to guide the reader into current work on the "chunking" of naturally occurring talk. It is conducted in the methodological frameworks of Conversation Analysis and Interactional Linguistics - two approaches that consider the interactional aspect of humans talking with each other to be a crucial starting point for its analysis. In doing so, we will (1) lay out the background of this special issue (what is problematic about "chunking" talk-in-interaction, the characteristics of the methodological approach chosen by the contributors, the cesura model), (2) highlight what can be gained from such a revised understanding of "chunking" in talk-in-interaction by referring to previous work with this model as well as the findings of the contributions to this special issue, and (3) indicate further directions such work could take starting from papers in this special issue. We hope to induce a fruitful exchange on the phenomena discussed, across methodological divides.}, language = {en} } @article{BauchKrtitschkaLinker2017, author = {Bauch, Marcel and Krtitschka, Angela and Linker, Torsten}, title = {Photooxygenation of oxygen-substituted naphthalenes}, series = {Journal of physical organic chemistry}, volume = {30}, journal = {Journal of physical organic chemistry}, publisher = {Wiley}, address = {Hoboken}, issn = {0894-3230}, doi = {10.1002/poc.3734}, pages = {6803 -- 6813}, year = {2017}, abstract = {The reaction of oxygen-substituted naphthalenes with singlet oxygen (O-1(2)) has been investigated, and labile endoperoxides have been isolated and characterized at -78 degrees C for the first time. Low-temperature kinetics by UV spectroscopy revealed that alkoxy and silyloxy substituents remarkably increase the rate of photooxygenations compared to 1,4-dimethylnaphthalene, whereas acyloxy-substituted acenes are inert towards O-1(2). The reactivities nicely correlate with HOMO energies and free activation energies, which we determined by density functional theory calculations. The lability of the isolated endoperoxides is due to their very fast back reaction to the corresponding naphthalenes even at -20 degrees C under release of O-1(2), making them to superior sources of this reactive species under very mild conditions. Finally, a carbohydrate-substituted naphthalene has been synthesized, which reacts reversibly with O-1(2) and might be applied for enantioselective oxidations in future work.}, language = {en} } @phdthesis{Sharma2023, author = {Sharma, Anjali}, title = {Optical manipulation of multi-responsive microgels}, school = {Universit{\"a}t Potsdam}, pages = {207}, year = {2023}, abstract = {This dissertation focuses on the understanding of the optical manipulation of microgels dispersed in aqueous solution of azobenzene containing surfactant. The work consists of three parts where each part is a systematic investigation of the (1) photo-isomerization kinetics of the surfactant in complex with the microgel polymer matrix, (2) light driven diffusiosmosis (LDDO) in microgels and (3) photo-responsivity of microgel on complexation with spiropyran. The first part comprises three publications where the first one [P1] investigates the photo-isomerization kinetics and corresponding isomer composition at a photo-stationary state of the photo-sensitive surfactant conjugated with charged polymers or micro sized polymer networks to understand the structural response of such photo-sensitive complexes. We report that the photo-isomerization of the azobenzene-containing cationic surfactant is slower in a polymer complex compared to being purely dissolved in an aqueous solution. The surfactant aggregates near the polyelectrolyte chains at concentrations much lower than the bulk critical micelle concentration. This, along with the inhibition of the photo-isomerization kinetics due to steric hindrance within the densely packed aggregates, pushes the isomer-ratio to a higher trans-isomer concentration for all irradiation wavelengths. The second publication [P2] combines experimental results and non-adiabatic dynamic simulations for the same surfactant molecules embedded in the micelles with absorption spectroscopy measurements of micellar solutions to uncover the reasons responsible for the slowdown in photo induced trans → cis azobenzene isomerization at concentrations higher than the critical micelle concentration (CMC). The simulations reveal a decrease of isomerization quantum yields for molecules inside the micelles and observes a reduction of extinction coefficients upon micellization. These findings explain the deceleration of the trans → cis switching in micelles of the azobenzene-containing surfactants. Finally, the third publication [P3] focusses on the kinetics of adsorption and desorption of the same surfactant within anionic microgels in the dark and under continuous irradiation. Experimental data demonstrate, that microgels can serve as a selective absorber of the trans isomers. The interaction of the isomers with the gel matrix induces a remotely controllable collapse or swelling on appropriate irradiation wavelengths. Measuring the kinetics of the microgel size response and knowing the exact isomer composition under light exposure, we calculate the adsorption rate of the trans-isomers. The second part comprises two publications. The first publication [P4] reports on the phenomenon of light-driven diffusioosmotic (DO) long-range attractive and repulsive interactions between micro-sized objects, whose range extends several times the size of microparticles and can be adjusted to point towards or away from the particle by varying irradiation parameters such as intensity or wavelength of light. The phenomenon is fueled by the aforementioned photosensitive surfactant. The complex interaction of dynamic exchange of isomers and photo-isomerization rate yields to relative concentrations gradients of the isomers in the vicinity of micro-sized object inducing a local diffusioosmotic (DO) flow thereby making a surface act as a micropump. The second publication [P5] exclusively aims the visualization and investigation of the DO flows generated from microgels by using small tracer particles. Similar to micro sized objects, the flow is able to push adjacent tracers over distances several times larger than microgel size. Here we report that the direction and the strength of the l-LDDO depends on the intensity, irradiation wavelength and the amount of surfactant adsorbed by the microgel. For example, the flow pattern around a microgel is directed radially outward and can be maintained quasi-indefinitely under exposure at 455 nm when the trans:cis ratio is 2:1, whereas irradiation at 365 nm, generates a radially transient flow pattern, which inverts at lower intensities. Lastly, the third part consists of one publication [P6] which, unlike the previous works, reports on the study of the kinetics of photo- and thermo-switching of a new surfactant namely, spiropyran, upon exposure with light of different wavelengths and its interaction with p(NIPAM-AA) microgels. The surfactant being an amphiphile, switches between its ring closed spiropyran (SP) form and ring open merocyanine (MC) form which results in a change in the hydrophilic-hydrophobic balance of the surfactant as MC being a zwitterionic form along with the charged head group, generates three charges on the molecule. Therefore, the MC form of the surfactant is more hydrophilic than in the case of the neutral SP state. Here, we investigate the initial shrinkage of the gel particles via charge compensation on first exposure to SP molecules which results from the complex formation of the molecules with the gel matrix, triggering them to become photo responsive. The size and VPTT of the microgels during irradiation is shown to be a combination of heating up of the solution during light absorption by the surfactant (more pronounced in the case of UV irradiation) and the change in the hydrophobicity of the surfactant.}, language = {en} } @phdthesis{Albers2006, author = {Albers, Nicole}, title = {On the relevance of adhesion : applications to Saturn's rings}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-10848}, school = {Universit{\"a}t Potsdam}, year = {2006}, abstract = {Since their discovery in 1610 by Galileo Galilei, Saturn's rings continue to fascinate both experts and amateurs. Countless numbers of icy grains in almost Keplerian orbits reveal a wealth of structures such as ringlets, voids and gaps, wakes and waves, and many more. Grains are found to increase in size with increasing radial distance to Saturn. Recently discovered "propeller" structures in the Cassini spacecraft data, provide evidence for the existence of embedded moonlets. In the wake of these findings, the discussion resumes about origin and evolution of planetary rings, and growth processes in tidal environments. In this thesis, a contact model for binary adhesive, viscoelastic collisions is developed that accounts for agglomeration as well as restitution. Collisional outcomes are crucially determined by the impact speed and masses of the collision partners and yield a maximal impact velocity at which agglomeration still occurs. Based on the latter, a self-consistent kinetic concept is proposed. The model considers all possible collisional outcomes as there are coagulation, restitution, and fragmentation. Emphasizing the evolution of the mass spectrum and furthermore concentrating on coagulation alone, a coagulation equation, including a restricted sticking probability is derived. The otherwise phenomenological Smoluchowski equation is reproduced from basic principles and denotes a limit case to the derived coagulation equation. Qualitative and quantitative analysis of the relevance of adhesion to force-free granular gases and to those under the influence of Keplerian shear is investigated. Capture probability, agglomerate stability, and the mass spectrum evolution are investigated in the context of adhesive interactions. A size dependent radial limit distance from the central planet is obtained refining the Roche criterion. Furthermore, capture probability in the presence of adhesion is generally different compared to the case of pure gravitational capture. In contrast to a Smoluchowski-type evolution of the mass spectrum, numerical simulations of the obtained coagulation equation revealed, that a transition from smaller grains to larger bodies cannot occur via a collisional cascade alone. For parameters used in this study, effective growth ceases at an average size of centimeters.}, subject = {Saturn}, language = {en} } @phdthesis{Vacogne2016, author = {Vacogne, Charlotte D.}, title = {New synthetic routes towards well-defined polypeptides, morphologies and hydrogels}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-396366}, school = {Universit{\"a}t Potsdam}, pages = {xii, 175}, year = {2016}, abstract = {Proteins are natural polypeptides produced by cells; they can be found in both animals and plants, and possess a variety of functions. One of these functions is to provide structural support to the surrounding cells and tissues. For example, collagen (which is found in skin, cartilage, tendons and bones) and keratin (which is found in hair and nails) are structural proteins. When a tissue is damaged, however, the supporting matrix formed by structural proteins cannot always spontaneously regenerate. Tailor-made synthetic polypeptides can be used to help heal and restore tissue formation. Synthetic polypeptides are typically synthesized by the so-called ring opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCA). Such synthetic polypeptides are generally non-sequence-controlled and thus less complex than proteins. As such, synthetic polypeptides are rarely as efficient as proteins in their ability to self-assemble and form hierarchical or structural supramolecular assemblies in water, and thus, often require rational designing. In this doctoral work, two types of amino acids, γ-benzyl-L/D-glutamate (BLG / BDG) and allylglycine (AG), were selected to synthesize a series of (co)polypeptides of different compositions and molar masses. A new and versatile synthetic route to prepare polypeptides was developed, and its mechanism and kinetics were investigated. The polypeptide properties were thoroughly studied and new materials were developed from them. In particular, these polypeptides were able to aggregate (or self-assemble) in solution into microscopic fibres, very similar to those formed by collagen. By doing so, they formed robust physical networks and organogels which could be processed into high water-content, pH-responsive hydrogels. Particles with highly regular and chiral spiral morphologies were also obtained by emulsifying these polypeptides. Such polypeptides and the materials derived from them are, therefore, promising candidates for biomedical applications.}, language = {en} } @article{GuRisseLuetal.2019, author = {Gu, Sasa and Risse, Sebastian and Lu, Yan and Ballauff, Matthias}, title = {Mechanism of the oxidation of 3,3′,5,5′-tetramethylbenzidine catalyzed by peroxidase-like Pt nanoparticles immobilized in spherical polyelectrolyte brushes}, series = {ChemPhysChem}, volume = {21}, journal = {ChemPhysChem}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1439-4235}, doi = {10.1002/cphc.201901087}, pages = {450 -- 458}, year = {2019}, abstract = {Experimental and kinetic modelling studies are presented to investigate the mechanism of 3,3 ',5,5 '-tetramethylbenzidine (TMB) oxidation by hydrogen peroxide (H2O2) catalyzed by peroxidase-like Pt nanoparticles immobilized in spherical polyelectrolyte brushes (SPB-Pt). Due to the high stability of SPB-Pt colloidal, this reaction can be monitored precisely in situ by UV/VIS spectroscopy. The time-dependent concentration of the blue-colored oxidation product of TMB expressed by different kinetic models was used to simulate the experimental data by a genetic fitting algorithm. After falsifying the models with abundant experimental data, it is found that both H2O2 and TMB adsorb on the surface of Pt nanoparticles to react, indicating that the reaction follows the Langmuir-Hinshelwood mechanism. A true rate constant k, characterizing the rate-determining step of the reaction and which is independent on the amount of catalysts used, is obtained for the first time. Furthermore, it is found that the product adsorbes strongly on the surface of nanoparticles, thus inhibiting the reaction. The entire analysis provides a new perspective to study the catalytic mechanism and evaluate the catalytic activity of the peroxidase-like nanoparticles.}, language = {en} } @article{ZhaoOpitzEljarratetal.2021, author = {Zhao, Yuhang and Opitz, Andreas and Eljarrat, Alberto and Kochovski, Zdravko and Koch, Christoph and Koch, Norbert and Lu, Yan}, title = {Kinetic study on the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane on Ag nanoparticles in chloroform}, series = {ACS applied nano materials}, volume = {4}, journal = {ACS applied nano materials}, number = {11}, publisher = {American Chemical Society}, address = {Washington}, issn = {2574-0970}, doi = {10.1021/acsanm.1c02153}, pages = {11625 -- 11635}, year = {2021}, abstract = {In this study, the kinetics of the adsorption of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F(4)TCNQ) on the surface of Ag nanoparticles (Ag NPs) in chloroform has been intensively investigated, as molecular doping is known to play a crucial role in organic electronic devices. Based on the results obtained from UV-visible (vis)-near-infrared (NIR) absorption spectroscopy, cryogenic transmission electron microscopy, scanning nanobeam electron diffraction, and electron energy loss spectroscopy, a two-step interaction kinetics has been proposed for the Ag NPs and F(4)TCNQ molecules, which includes the first step of electron transfer from Ag NPs to F(4)TCNQ indicated by the ionization of F(4)TCNQ and the second step of the formation of a Ag-F(4)TCNQ complex. The whole process has been followed via UV-vis-NIR absorption spectroscopy, which reveals distinct kinetics at two stages: the instantaneous ionization and the long-term complex formation. The kinetics and the influence of the molar ratio of Ag NPs/F(4)TCNQ molecules on the interaction between Ag NPs and F(4)TCNQ molecules in an organic solution are reported herein for the first time. Furthermore, the control experiment with silica-coated Ag NPs manifests that the charge transfer at the surface between Ag NPs and F(4)TCNQ molecules is prohibited by a silica layer of 18 nm.}, language = {en} } @article{KhajooeiWochatzBaritelloetal.2020, author = {Khajooei, Mina and Wochatz, Monique and Baritello, Omar and Mayer, Frank}, title = {Effects of shoes on children's fundamental motor skills performance}, series = {Footwear science : official journal of the Footwear Biomechanics Group}, volume = {12}, journal = {Footwear science : official journal of the Footwear Biomechanics Group}, number = {1}, publisher = {Taylor \& Francis}, address = {Abingdon}, issn = {1942-4280}, doi = {10.1080/19424280.2019.1696895}, pages = {55 -- 62}, year = {2020}, abstract = {Progression or impediment of fundamental motor skills performance (FMSP) in children depends on internal and environmental factors. Shoes as an environmental constraint are believed to affect these movements as children showed to perform qualitatively better with sports shoes than flip-flop sandals. However, locomotor performance assessments based on biomechanical variables are limited. Therefore, the objective of this experiment was to assess the biomechanical effects of wearing shoes while performing fundamental motor skills in children. Barefoot and shod conditions were tested in healthy children between the age of 4 and 7 years. They were asked to perform basic and advanced motor skills including double-leg stance, horizontal jumps, walking as well as counter-movement jumps, single-leg stance and sprinting. Postural control and ground reaction data were measured with two embedded force plates. A 3D motion capture system was used to analyse the spatiotemporal parameters of walking and sprinting. Findings showed that the parameters of single- and double-leg stance, horizontal and counter-movement jump did not differ between barefoot and shod conditions. Most of the spatiotemporal variables including cadence, stride length, stride time, and contact time of walking and sprinting were statistically different between the barefoot and shod conditions. Consequently, tested shoes did not change performance and biomechanics of postural control and jumping tasks; however, the spatiotemporal gait parameters indicate changes in walking and sprinting characteristics with shoes in children.}, language = {en} } @misc{QuarmbyMoennigMugeleetal.2023, author = {Quarmby, Andrew James and M{\"o}nnig, Jamal and Mugele, Hendrik and Henschke, Jakob and Kim, MyoungHwee and Cassel, Michael and Engel, Tilman}, title = {Biomechanics and lower limb function are altered in athletes and runners with achilles tendinopathy compared with healthy controls: A systematic review}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {830}, issn = {1866-8364}, doi = {10.25932/publishup-58760}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-587603}, pages = {20}, year = {2023}, abstract = {Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95\% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of "medial collapse". Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.}, language = {en} }