1,524 research outputs found
Developments in X-ray diffraction microscopy with applications for biological imaging
No full text© 2014 Dr. Guido Andrew CadenazziPublications included in thesis:Williams, G. J., Hanssen, E., Peele, A. G., Pfeifer, M. A., Clark, J., Abbey, B., & Cadenazzi, G. et al. (2008). High resolution X-ray imaging of Plasmodium falciparum infectedred blood cells. Cytometry, Part A (73), 949-957. DOI: 10.1002/cyto.a.20616Putkunz, C. T., Clark, J. N., Vine, D. J., Williams, G. J., Balaur, E., Cadenazzi, G. A. et al. (2011). Mapping granular structure in the biological adhesive of Phragmatopomacalifornica using phase diverse coherent diffractive imaging. Ultramicroscopy, 111(8), 1184-1188. DOI: 10.1016/j.ultramic.2011.03.022Abbey, B., Whitehead, L. W., Quiney, H. M., Vine, D. J., Cadenazzi, G. A., Henderson, C. A. et al. (2011). Lensless imaging using broadband X-ray sources. Nature Photonics, 5, 420-424. DOI: doi:10.1038/nphoton.2011.125Vartanyants, I. A., Singer, A., Mancuso, A. P., Yefanov, O., Sakdinawat, A., Liu, Y. et al. (2011). Coherence properties of individual femtosecond pulses of an X-rayfree-electron laser. Physical Review Letters, 107(14), 144801. DOI: 10.1103/PhysRevLett.107.144801Schlotter, W. F., Turner, J. J., Rowen, M., Heimann, P., Holmes, M., Krupin, O. et al. (2012). The soft X-ray instrument for materials studies at the linac coherentlight source X-ray free-electron laser. Review of Scientifc Instruments, 83(4), 043107. DOI: 10.1063/1.3698294Peterson, I., Abbey, B., Putkunz, C. T., Vine, D. J., van Riessen, G., Cadenazzi, G. A. et al. (2012). Nanoscale Fresnel coherent diffraction tomography using ptychography. Optics Express, 20(22), 24678-24685. DOI: 10.1364/OE.20.024678.Luu, M. B., van Riessen, G. A., Phillips, N. W., Elgass, K., Junker, M., Abbey, B. et al. (2014). Fresnel coherent diffractive imaging tomography of whole cells in capillaries. New Journal of Physics, 16. DOI: 10.1088/1367-2630/16/9/093012Macroscopic dynamics in biological systems are driven by signalling events between a host of microscopic sub-structures. At the molecular level, signals propagate along molecular circuitry that is mediated by signalling and receptor agents such as hormones, enzymes, neurotransmitters, cell membrane proteins, ion channels and others. At a cellular level, organelle functionality is crucial for cellular respiration and cellular division as well as protein synthesis and trafficking. Clearly, much can be learned from the size, shape and composition of the microscopic structures that regulate homeostasis.
X-ray microscopy has established itself as a highly capable technique that surpasses the resolution limits of optical microscopy while circumventing the weak penetration and extensive sample preparation characteristic of electron microscopy. Lens based, optical microscopes have the advantage of producing images in real time but, apart from some forms of fluorescence microscopy, their resolution is fundamentally limited to the quality of the lens. We here discuss a powerful alternative known as X-ray Diffraction Microscopy (XDM). Removing the focussing optic means that XDM is unaffected by issues such as lens quality. Images are reconstructed from the diffraction
pattern meaning that image resolution is given by the largest scattered angle detected. For biological materials the ability to record high angle is limited by radiation damage however, new techniques demonstrate that if the scattering is recorded sufficiently rapidly, radiation damage can be circumvented and wavelength limited resolution could be possible.
Chapters 1 to 4 comprise introductory and review chapters that outline the theory and experimental work necessary to describe the original work presented in this thesis. In Chapter 5 we discuss the application of curved beam XDM to malaria infected red blood cells. The life cycle of this deadly disease is still not fully understood and we approach the problem from a structural biology perspective. Using a variety of infected blood cells, we explore the possibility of imaging intact cells to high resolution and without extensive sample preparation. The method is shown to be sensitive to internal cellular structure and to return high resolution images that are consistent with the accompanying SEM and optical micrographs at a resolution of ∼ 40 nm. In Chapter 6 we discuss the importance of 3D imaging and present a simple method for mounting samples in heat-thinned glass capillaries. To support the premise that this method is ideal for tomographic analysis we present preliminary results of tomographic curved beam XDM of malaria infected red blood cells mounted in glass capillaries.
To address the data collection overhead imposed by imaging weakly scattering samples in a tomographic format, we challenge the notion that XDM requires fully coherent flux. Standard XDM implicitly assumes full temporal and spatial coherence. These conditions are achieved using spatial and spectral filters that remove the overwhelming majority of the radiation available. We explore the possibility of relaxing the spatial and temporal coherence requirements in order to exploit a larger fraction of the undulator radiation. In Chapter 7 we present the first demonstration of XDM data collection and image reconstruction using a broadband x-ray beam. A multi-modal reconstruction algorithm is then used to propagate the beam between real and reciprocal space. The analysis shows that by imaging structures with a partially temporally coherent beam, the data acquisition times are reduced by a factor of 60. Chapter 8 extends this work in a simulation study by analysing the effect of partial spatial coherence. We demonstrate that a reconstruction algorithm that includes the spatial coherence properties can recover a simple object with no a priori information. The results from both chapters show that if the coherence properties are accounted for in the reconstruction, significant departures from full coherence are tolerable with commensurate decreases in the required exposure time.
The final chapter changes tack and focuses on the source of radiation itself. A surge of investment in new x-ray sources over the last decade is representative of the growing interest in the field. New x-ray facilities known as X-ray Free Electron Lasers (XFELs) are currently being developed and will allow methods of biological imaging that are impossible at 3rd generation sources. Unlike synchrotron sources, XFELs provide ultra short pulses of intrinsically coherent radiation. Chapter 9 describes spatial coherence measurements of individual femto-second pulses of a hard x-ray free electron laser. Using the well known “diffract and destroy” technique, we apply the classic Young’s double pinhole experiment to probe the coherence of individual pulses. Our results show that in the absence of spatial filters, the majority of the x-ray flux is contained within the fundamental spatial coherence mode and thus confirms the coherent nature of XFEL pulses
"La materia quando inizia a soffrire": Denial Figures in Guido Morselli's Work
No full textopenIl presente lavoro si propone di indagare la questione della crisi del soggetto così come discussa dall'autore italiano Guido Morselli, nelle diverse sedi dei romanzi, della produzione saggistica e del diario personale. Da qui si analizzeranno temi quali il solipsismo e gli interrogativi esistenziali, fin dai loro primi riverberi nella filosofia centro-europea di fine Ottocento, inizio Novecento.The present work aims yo investigate the issue of the crisis of the subject, as it is discussed by the Italian author Guido Morselli, on his novels, essays and personal diary. We will also analyze topics such as solipsism and existential questions from their first reverberations on the late eighteen century and early nineteen century middle European philosophy
"Sailing around the World (1857-1859). Colonial Patterns, Native Societies, Global Resources in the Circumnavigation of the Austrian Frigate Novara"
No full textThis essay by Guido Abbattista analyzes the Austrian frigate Novara’s circumnavigation (1857–1859) as a paradigmatic case of nineteenth-century global exploration, set within the broader context of European imperial expansion and scientific ambition. Abbattista demonstrates how the Novara expedition, Austria’s first global voyage, was not only a naval and scientific enterprise but also a vehicle for projecting imperial prestige, asserting national identity, and gathering knowledge about colonial patterns, native societies, and global resources. Drawing on official reports, scientific publications, and ethnographic collections, the essay situates the Novara alongside other Austrian and European voyages, highlighting its role in consolidating Austria’s place on the world stage. The author explores the ideological underpinnings of the mission, especially as articulated by Karl von Scherzer, who framed the journey in terms of Eurocentric progress, racial hierarchies, and the civilizing mission of Europe—particularly the “Anglo-Saxon” model. The essay critically examines how the Novara’s documentation and collections contributed to museums and scientific institutions, while also reflecting the contradictions and exclusions of imperialist worldviews. Ultimately, Abbattista argues that the Novara expedition exemplifies the entanglement of science, empire, and global modernity, offering insight into the construction of “global Europeanness” and the enduring legacies of colonial encounters
Erratum to: Association Study between Coronary Artery Disease and rs1333049 Polymorphism at 9p21.3 Locus in Italian Population (Journal of Cardiovascular Translational Research, (2017), 10, 5-6, (455-458), 10.1007/s12265-017-9758-9)
No full textThe author affiliation for both Guido Iaccarino and Michele Ciccarelli is Medicine, Surgery and Dentistry, Scuola Medica Salernitana, University of Salerno. The currently mentioned affiliations (Department of Advanced Biomedical SciencesFederico II University NaplesItaly and IRCCS SDN Istituto di Ricerca Diagnostica e Nucleare Naples Italy respectively) are not correct
Missa luba : new edition and conductor's analysis
No full text"Since 1964 and the first printed edition of Missa Luba by Guido Haazen, this work has been performed countless numbers of times all over the world. Missa Luba continues to have a large number of performances each year, despite the fact that there is very little research available, and the only published edition is wholly insufficient in producing an authentic performance. To date, the following has not been published in any known academic publications: 1) a biography of Guido Haazen, 2) research into the first choir to sing Missa Luba, 3) a detailed explanation of the collective improvisational nature of the work, and 4) a comparison of the folk melodies used as models to the corresponding sections of each Mass movement. The purpose of this document is to provide a new edition of Missa Luba and an analysis of the work useful to a conductor. The reasons why a new edition is needed and what changes are made to the existing edition will be discussed, along with an analysis, which will cover the work's historical background, structure, and performance practice concerns. The document will incorporate recent research into this subject, especially that of interviews with Guido Haazen prior to his death in 2004, and a more accurate transcription of the original 1958 recording. Also, significant to this project is a description of the ethnic instruments used in the original performances of Missa Luba and suitable modern substitutions. Research conducted at the Central Africa Museum in Tervuren, Belgium will be primary in this discussion. The result of this document will be a new edition of Missa Luba, more accurately reflective of the 1958 recording and early performances, and will provide much needed research into its creation, structure, and performance. "--Abstract from author supplied metadata
Guido Fassò. Un itinerario filosofico tra diritto e natura umana
No full textWith this essay the author intends to examine the fundamental themes of the reflections of Guido Fassò, highlighting the relationship between juridical and moral experience, and following the genesis of this Bolognese philosopher's peculiar natural law approach which has both a sociological and realistic character
Diventare bolognese. L’ebreo converso Ippolito Boncompagni e i suoi legami con Guido Reni, Guido Signorini e Domenichino
No full textBecoming Bolognese: The Converted Jew Ippolito Boncompagni and his
Relationship
with Guido Reni, Guido Signorini and Domenichino
The essay moves from an introduction on Guido Reni’s friendship with the converted
Jew Ippolito Boncompagni, formerly Ruben Corcos, and presents the story
of the conversion of the four Corcos brothers (all of whom were baptized as
Catholics
in 1592 and took the name Boncompagni) as the backdrop to a discussion
of the Boncompagni collection of paintings inventoried in 1657. This
collection featured a remarkable number of Bolognese and Emilian works by
painters such as Reni, Guercino, Domenichino, Lanfranco, Albani, Sementi.
Through an analysis of the documents, it is established that a substantial number
of the works were owned by Ippolito, and the identification of some of them is
attempted. The study then focuses on Reni’s cousin and heir, the painter Guido
Signorini, bringing to light hitherto unpublished documents and new information
on the friendship between Signorini and Ippolito, and providing a close
reading of archival material concerning Reni’s will, inventory and Signorini’s
inheritance. The final section focuses on Ippolito and Domenichino. Archival
documents show that Ippolito
was financially involved not only with Guido
Reni, but also with Domenichino,
possibly as early as 1621–1623, and – after the
painter’s death in 1641 – with his widow. The Boncompagni owned two paintings
by Domenichino, one of which is an unknown Rebuke of Adam and Eve.
Expanding
on Richard Spear’s insights into the unusual iconography of another
version of the Rebuke by Domenichino
now in the Museum of Grenoble, the
author hypothesizes that these anomalies could reflect the Corcos’ Jewish background.
Finally, the study presents an interpretation of Boncompagni artistic
patronage
and collecting as instruments of self-representation, as well as means
to gain and consolidate social acceptanc
Un lungo percorso con Guido
No full textThe essay looks back at the most important steps of the relationship between the author and his friend Guido Davide Neri: it is remembered the different way they used to approach the philosophy of history, in particular Marxism, although they were both students of the same professor, Banfi. Their attitude towards the historical background of those years was different too because Neri moved towards socialism, made a theoretical-philosophical consideration, while Papi was more pragmatic and focused on practical policy. The author runs through the philosophical season of 70’s shared and experienced with his friend, when the theoretical background of the University of Milan was focused on the Husserl’s lifeworld, inaugurated in Italy by Enzo Paci
Guido da Pisa e la «Consolatio philosophiae»
No full textL’articolo considera le occorrenze della Consolatio philosophiae di Boezio nelle Expositiones di Guido da Pisa, rilevando il carattere sistematico e l’originalità dell’approccio
del frate carmelitano al prosimetro tardoantico rispetto ai commenti danteschi precedenti.
Oltre a sottolineare la predilezione guidiana per gli excursus boeziani di contenuto mito-
logico, l’autore si sofferma sull’impiego retorico-stilistico della fonte tardoantica da parte
di Guido, che pare cogliere notevoli convergenze macrostrutturali tra la Consolatio e la
Commedia, sin dall’accostamento intertestuale proposto per Inf. II, 7-9. Parte dell’indagine
è rivolta poi a precisare la definizione di Boezio come poeta lirico, che Guido formula in
relazione alla varietà dei ritmi e alla dolcezza del suono che a suo giudizio contraddistin-
guono tanto il prosimetro quanto l’opera dantesca. Emergono inoltre non sporadici casi
nei quali è dimostrato come la ricezione guidiana della Consolatio venisse filtrata dal for-
tunato commento del domenicano inglese Nicola Trevet, del quale sono tracciati i percorsi
culturali e di essi l’indubbia contiguità con l’esegesi guidiana.The article considers the occurrences of Boethius’ Consolatio philosophiae in Guido
da Pisa’s Expositiones, noting the systematic nature and the originality of the approach of
the Carmelite friar to the Late Antique prosimetro as compared to other of Dante’s previous
commentators. In addition to emphasizing Guido’s predilection for a boethian overview
of mythological content, the author dwells on the rhetorical and stylistic use of the Late
Antique source by Guido, who seems to capture remarkable macro-structural
convergences between the Consolatio and the Commedia, starting from the intertextual
combination proposed at Inf. II, 7-9. Part of the investigation is then directed to clarify the
definition of Boethius as a lyric poet, expressed by Guido in relation to the variety of
rhythms and the sweetness of sound that, in his judgment, characterize the prosimetro as
well as Dante’s work. Cases also emerge in which it is shown that Guido’s reception of
the Consolatio was filtered by the widespread commentary of the English Dominican
Nicholas Trevet; the undoubted cultural contiguity between this work and Guido’s own
exegesis are explored
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