Dynamic buckling of actin within filopodia

Filopodia are active tubular structuresprotruding from the cell surface which allow the cell to sense and interact with the surrounding environment through repetitive elongation-retraction cycles. The mechanical behavior of filo-podia has been studied by measuring the traction forces exerted on external sub-strates.1 These studies have revealed that internal actin flow can transduce a force across the cell surface through transmem-brane linkers like integrins. In addition to the elongation-retraction behavior filo-podia also exhibit a buckling and rota-tional behavior. Filopodial buckling in conjunction with rotation enables th

Eagrán de na scéalta idirnáisiúnta ó na Cruacha Gorma a bhailigh Seán Ó hEochaidh do Choimisiún Béaloideasa Éireann i 1947 agus 1948

Sa saothar seo, cuirtear in eagar tríocha scéal idirnáisiúnta a bailíodh sna Cruacha Gorma i dTír Chonaill sna blianta 1947 agus 1948. Is iad na haidhmeanna atá ag an saothar: 1. Eagrán de na scéalta seo a chur ar fáil don chéad uair, scéalta nár cuireadh in eagar cheana. 2. Gaeilge na scéalta a chaighdeánú de réir Foclóir Gaeilge-Béarla, (Ó Dónaill, 1977) agus Gramadach na Gaeilge agus Litriú na Gaeilge, An Caighdeán Oifigiúil, (2004), ach amháin nuair a bhíonn coimhlint idir an Caighdeán agus canúint na scéalaithe mar a scríobhadh síos í ag an bhailitheoir, Seán Ó hEochaidh. Nuair a bhíonn coimhlint idir an Caighdeán agus an chanúint, taobhaítear leis an chanúint sa saothar. 3. An méid staidéir atá déanta cheana ar bhéaloideas na gCruach, agus ar an ról éachtach a bhí ag Ó hEochaidh ina chaomhnú a mhéadú. Bhailigh Seán Ó hEochaidh na scéalta seo do Chomisiúin Béaloideasa Éireann, agus tá lámhscríbhinní an bhailitheora caomhnaithe mar chuid de Chnuasach Bhéaloideas Éireann (CBÉ) sa Choláiste Ollscoile, Baile Átha Cliath. Is iad na lámhscríbhinní seo, a bhfuil fáil orthu chomh maith i bhfoirm mhicreascannán i leabharlann Ollscoil na hÉireann, Má Nuad, a úsáidtear mar bhunábhar sa saothar. I gCaibidil 1, tugtar an modh eagarthóireachta a chuirtear i bhfeidhm ar théacsanna na scéalta, na hathruithe i dtreo an Chaighdeáin a dhéantar, agus na hathruithe nach gcuirtear i bhfeidhm nuair a dhéantar iarracht tús áite a thabhairt do chanúint na scéalaithe. I gCaibidil 2, déantar plé ar cheithre ábhar inspéise de Ghaeilge na gCruach a tháinig chun cinn nuair a bhí na scéalta á gcur in eagar. I gCaibidil 3, tugtar tríocha scéal idirnáisiúnta agus iad curtha in eagar. Chomh maith leis an phlé a dhéantar ar Ghaeilge na scéalta, mar a luadh thuas, cuirtear athruithe i bhfeidhm i bponcaíocht agus i leagan amach théacs na scéalta. I gCaibidil 4 déantar plé ar scéal amháin sa chnuasach, scéal an Fhir Mhóir. Bailíodh dhá leagan den scéal seo ón scéalaí, Anna Nic an Luain, Cruach Thoibrid, agus faightear idir chosúlachtaí agus éagsúlachtaí sna leaganacha seo. Déantar comparáid idir an dá leagan sin, chomh maith le plé a dhéanamh ar an scéal mar a bailíodh é sna Cruacha agus i gceantracha eile i dTir Chonaill. Sa chéad aguisín a théann leis an saothar seo, tugtar eolas ar na scéalta a fhaightear ann. Tugtar ainmneacha na scéalta, uimhreacha na scéalta de réir chlár Aarne/Thompson/Uther (ATU), agus cur síos ar na scéalta idirnáisiúnta a fhaightear iontu, ainmneacha na scéalaithe agus cad as a bhfuair siad a gcuid scéalta, má tá an teolas sin ar fáil sna lámhscríbhinní. Sa dara aguisín, tugtar leagan na lámhscríbhinní den scéal An luchóg ý an bheacóg, díreach mar a scríobh Seán Ó hEochaidh síos é ón scéalaí Anna Nic an Luain. Sa tríú aguisín, tugtar liosta iomlán de na scéalta idirnáisiúnta a bailíodh sna Cruacha Gorma i 1947 agus 1948

Continuous cocrystallization of benzoic acid and isonicotinamide by mixing-induced supersaturation : exploring opportunities between reactive and antisolvent crystallization concepts

This study combines reactive and antisolvent crystallization concepts via mixing-induced supersaturation to demonstrate a wider range of options for solvent system selection in multicomponent crystallization. This approach was applied to investigate continuous crystallization of 1:1 and 2:1 cocrystals of benzoic acid and isonicotinamide. Design of Experiments was used to identify conditions where pure cocrystal phases are obtained and a continuous mixing-induced cocrystallization process was implemented to selectively produce either 1:1 or 2:1 cocrystals

Dynamics of membrane nanotubes coated with I-BAR

Membrane deformation is a necessary step in a number of cellular processes such as filopodia and invadopodia formation and has been shown to involve membrane shaping proteins containing membrane binding domains from the IRSp53-MIM protein family. In reconstituted membranes the membrane shaping domains can efficiently deform negatively charged membranes into tubules without any other proteins present. Here, we show that the IM domain (also called I-BAR domain) from the protein ABBA, forms semi-flexible nanotubes protruding into Giant Unilamellar lipid Vesicles (GUVs). By simultaneous quantification of tube intensity and tubular shape we find both the diameter and stiffness of the nanotubes. I-BAR decorated tubes were quantified to have a diameter of ~50 nm and exhibit no stiffening relative to protein free tubes of the same diameter. At high protein density the tubes are immobile whereas at lower density the tubes diffuse freely on the surface of the GUV. Bleaching experiments of the fluorescently tagged I-BAR confirmed that the mobility of the tubes correlates with the mobility of the I-BAR on the GUV membrane. Finally, at low density of I-BAR the protein upconcentrates within tubes protruding into the GUVs. This implies that I-BAR exhibits strong preference for negatively curved membranes

Single Particle and PET-based Platform for Identifying Optimal Plasmonic Nano-Heaters for Photothermal Cancer Therapy

Plasmonic nanoparticle-based photothermal cancer therapy is a promising new tool to inflict localized and irreversible damage to tumor tissue by hyperthermia, without harming surrounding healthy tissue. We developed a single particle and positron emission tomography (PET)-based platform to quantitatively correlate the heat generation of plasmonic nanoparticles with their potential as cancer killing agents. In vitro, the heat generation and absorption cross-section of single irradiated nanoparticles were quantified using a temperature sensitive lipid-based assay and compared to their theoretically predicted photo-absorption. In vivo, the heat generation of irradiated nanoparticles was evaluated in human tumor xenografts in mice using 2-deoxy-2-[F-18]fluoro-D-glucose ((18)F-FDG) PET imaging. To validate the use of this platform, we quantified the photothermal efficiency of near infrared resonant silica-gold nanoshells (AuNSs) and benchmarked this against the heating of colloidal spherical, solid gold nanoparticles (AuNPs). As expected, both in vitro and in vivo the heat generation of the resonant AuNSs performed superior compared to the non-resonant AuNPs. Furthermore, the results showed that PET imaging could be reliably used to monitor early treatment response of photothermal treatment. This multidisciplinary approach provides a much needed platform to benchmark the emerging plethora of novel plasmonic nanoparticles for their potential for photothermal cancer therapy

FBAR syndapin 1 recognizes and stabilizes highly curved tubular membranes in a concentration dependent manner

Syndapin 1 FBAR, a member of the Bin-amphiphysin-Rvs (BAR) domain protein family, is known to induce membrane curvature and is an essential component in biological processes like endocytosis and formation and growth of neurites. We quantify the curvature sensing of FBAR on reconstituted porcine brain lipid vesicles and show that it senses membrane curvature at low density whereas it induces and reinforces tube stiffness at higher density. FBAR strongly up-concentrates on the high curvature tubes pulled out of Giant Unilamellar lipid Vesicles (GUVs), this sorting behavior is strongly amplified at low protein densities. Interestingly, FBAR from syndapin 1 has a large affinity for tubular membranes with curvatures larger than its own intrinsic concave curvature. Finally, we studied the effect of FBAR on membrane relaxation kinetics with high temporal resolution and found that the protein increases relaxation time of the tube holding force in a density-dependent fashion