| 1. |
- La Mendola, D., et al.
(författare)
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Copper binding to naturally occurring, lactam form of angiogenin differs from that to recombinant protein, affecting their activity
- 2016
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Ingår i: Metallomics. - : Oxford University Press (OUP). - 1756-5901 .- 1756-591X. ; 8:1, s. 118-124
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Tidskriftsartikel (refereegranskat)abstract
- Angiogenin is a member of the ribonuclease family and a normal constituent of human plasma. It is one of the most potent angiogenic factors known and is overexpressed in different types of cancers. Copper is also an essential cofactor in angiogenesis and, during this process, it is mobilized from inside to outside of the cell. To date, contrasting results have been reported about copper(II) influencing angiogenin activity. However, in these studies, the recombinant form of the protein was used. Unlike recombinant angiogenin, that contains an extra methionine with a free terminal amino group, the naturally occurring protein present in human plasma starts with a glutamine residue that spontaneously cyclizes to pyroglutamate, a lactam derivative. Herein, we report spectroscopic evidence indicating that copper(II) experiences different coordination environments in the two protein isoforms, and affects their RNase and angiogenic activity differently. These results show how relatively small differences between recombinant and wild type proteins can result in markedly different behaviours.
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| 2. |
- Mangini, F., et al.
(författare)
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Self-imaging dynamics in nonlinear GRIN multimode optical fibers
- 2020
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Ingår i: Optics InfoBase Conference Papers. - : Optica Publishing Group. - 9781943580804
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Konferensbidrag (refereegranskat)abstract
- We study nonlinear self-imaging dynamics in graded-index multimode optical fibers. Side-scattering of light that accompanies the propagation of intense femtosecond pulses permits us to directly measure the self-imaging period.
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| 3. |
- Zitelli, M., et al.
(författare)
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Spatiotemporal guided bullets in multimode fiber
- 2021
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Ingår i: NONLINEAR FREQUENCY GENERATION AND CONVERSION: MATERIALS AND DEVICES XX. - : SPIE-INT SOC OPTICAL ENGINEERING. - 9781510641761
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Konferensbidrag (refereegranskat)abstract
- Beam self-imaging of ultrashort pulses in nonlinear graded-index (GRIN) multimode optical fibers is of interest for many applications, including spatiotemporal mode-locking in fiber lasers. We obtained a new analytical description for the nonlinear evolution of a laser beam of arbitrary transverse shape propagating in a GRIN fiber. The longitudinal beam evolution could be directly visualized by means of femtosecond laser pulses, propagating in the anomalous or in the normal dispersion regime, leading to light scattering out of the fiber core via the emission of blue photo-luminescence. As the critical power for self-focusing is approached and even surpassed, a host of previously undisclosed nonlinear effects is revealed, including strong multiphoton absorption by oxygen-deficiency center defects and Germanium inclusions, splitting and shifting of the self-imaging period, filamentation, and conical emission of the guided light bullets. We discovered that nonlinear loss has a profound influence on the process of high-order spatiotemporal soliton fission. The beam energy carried by the fiber is clamped to a fixed value, and nonlinear bullet attractors with suppressed Raman frequency shift and fixed temporal duration are generated, leading to highly efficient frequency conversion of the input near-infrared femtosecond pulses into mid-infrared multimode solitons.
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