The PoL PhD and Po stdoc seminar is a meeting where PoL early career scientists present their research to their peers. All are welcome!&\;nbsp\;
The seminar c onsists of two short talks by PhD students or Postdocs\, each followed by a discussion in which speaker and attendants can exchange ideas\, engage i n scientific discussions and network with their fellow young scientists.
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The talks:
Embryos reliably partition their cytoplasm into cells using large c ytoskeletal structures. Yet the very structures responsible for this proce ss harbor an intrinsic organizational instability. To uncover the rules go verning this instability\, we developed continuum and high-performance age nt-based simulations that reproduce the experimental microtubule density p rofiles observed in&\;nbsp\;large cytoskeletal structures. By fitting t hese profiles\, we extracted otherwise inaccessible microscopic and phenom enological parameters\, identifying a competition between microtubule orie ntation-dependent inhibition\, autocatalytic nucleation\, and nucleation f rom organizing centers. These parameters determine whether a structure is unstable and how long the instability takes to grow.&\;nbsp\;Strikingly \, some organisms rely on inherently&\;nbsp\;unstable conditions&\;n bsp\;to efficiently sense the geometry of their space. However\, it appear s&\;nbsp\;cells tame this innate volatility by having a&\;nbsp\;cell cycle is faster than instability growth. Together\, our results show that the interplay between physical instabilities and biological clocks underl ies strategies for rapid and robust spatial organization of biological str uctures.
Solid-liquid interfaces exist in many biological and env ironmental systems\, where the interfacial water structure and surface che mistry critically influences the reactivity. Despite its importance\, extr acting the molecular-level insight into water organization at such interfa ces under realistic conditions remains a major challenge. Amongst differen t oxide materials\, iron oxides are ubiquitous in nature and widely applie d in technological applications\, biological contexts\, and catalytic proc esses. Magnetite (Fe₃O₄) is particularly interesting due to its mixed oxidation state\, electronic conductivity\, and relevance in redox chemist ry. On contact with water especially with pH-variant aqueous media\, the F e3O4 surface tend to protonate or deprotonate resulting in the modulation of its surface charge and interfacial structure – a process conceptually analogous to pH-dependent behavior at biological membranes and protein su rfaces.
In my talk\, I will discuss how water molecules arrange
and orient at the magnetite–water interface as a function of pH\, using
interface-specific vibrational sum frequency generation (SFG) spectroscopy
. Due to its selection rule\, a vibrational spectrum of only the interfaci
al species is obtained in case of centrosymmetric\, making it well suited
to studying realistic\, life-relevant environments. The results reveal pH-
dependent changes in hydrogen-bonding strength\, water orientation\, and t
he emergence of surface Fe–OH species under alkaline conditions. By comp
aring magnetite to hematite (Fe₂O₃)\, we identify how oxidation state
and surface chemistry shape interfacial water structure. These findings pr
ovide a molecular-level picture of how water may mediate interactions at c
omplex hydrated interfaces.
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For those who cannot join o n site\, a Zoom option will be available:
https://t
u-dresden.zoom-x.de/j/63359118163?pwd=XNnQgKbbSzWItRfok1GxvDHeVaIS9E.1
Meeting ID: 633 5911 8163
Passcode: @T206x=%