Search results for "EMT"
showing 10 items of 413 documents
Dynamical binary modulation of ultrabroadband light beams by using principal states of polarization of liquid crystal devices
2009
Dynamical modulation of ultrabroadband beams, such as those produced by femtosecond laser or incoherent sources, is not an easy task due to the dispersive nature of the devices commonly employed. Phase modulation has been performed by means of deformable micromirror arrays. These devices are expensive and do not permit amplitude modulation. For micro- and nano-structuring of materials with femtosecond lasers is common to pattern the surface with the light irradiance produced by a computer generated hologram implemented onto a liquid crystal (LC) type spatial light modulator. This enables dynamical patterning [1,2]. Reduced spectral bandwidths, of the order of tens of nanometers, have been u…
Characterization of heat-labile toxin-subunit B from Escherichia coli by liquid chromatography-electrospray ionization-mass spectrometry and matrix-a…
2012
The possibilities of characterizing the heat-labile enterotoxin (LT) of enterotoxigenic Escherichia coli (ETEC) by liquid chromatography electrospray mass spectrometry (LC/ESI-MS) and matrix-assisted laser desorption with time-of-flight mass spectrometry (MALDI-TOF-MS) were investigated. The B subunit from recombinant E. coli (expression in Pichia pastoris) can be detected by LC/ESI-MS expressed in P. pastoris and the charge envelope signals can be observed; LC/ESI-MS and MALDI-TOF-MS analysis allowed the acquisition of labile toxin subunit B (LTB) molecular weight and preliminary structural characterization of LTB toxin. MALDI-TOF analysis after reduction and alkylation of the protein evid…
Cell and Tissue Response to Modified by Laser-induced Periodic Surface Structures Biocompatible Materials for Dental Implants
2016
The use of femtosecond laser-induced periodic surface structures (LIPSS) for dental implants surface modification for improving cell adhesion and proliferation is reported. Results demonstrated higher response of cells on modified surface compared to untreated ones.
Disclosing the emissive surface traps in green-emitting carbon nanodots
2021
Abstract The bright photoluminescence of surface-functionalized carbon nanoparticles, known as carbon nanodots (CDs), has been studied for more than a decade because of its fundamental photo-physical interest and strong technological potential. However, the essential nature of the electronic states involved in their typical light emission remains very elusive. Here, we provide conclusive evidence that surface carboxylic moieties are the key to CD fluorescence. The synergy of nanosecond and femtosecond optical studies, cryogenic fluorescence, computational investigations and chemical engineering of a strategically chosen model CD system, allows to demonstrate that their visible-light transit…
Radiation tolerant fiber Bragg gratings for high temperature monitoring at MGy dose levels
2014
International audience; We report a method for fabricating fiber Bragg gratings (FBG) resistant to very severe environments mixing high radiation doses (up to 3 MGy) and high temperatures (up to 230 degrees C). Such FBGs have been written in two types of radiation resistant optical fibers (pure-silica and fluorine-doped cores) by exposures to a 800 nm femtosecond IR laser at power exceeding 500 mW and then subjected to a thermal annealing treatment of 15 min at 750 degrees C. Under radiation, our study reveals that the radiation induced Bragg wavelength shift (BWS) at a 3 MGy dose is strongly reduced compared to responses of FBGs written with nonoptimized conditions. The BWS remains lower t…
A study of electron transfer in Ru(dcbpy)2(NCS)2 sensitized nanocrystalline TiO2 and SnO2 films induced by red-wing excitation.
2008
Excited state dynamics and electron transfer from the Ru(dcbpy)2(NCS)2 (RuN3) sensitizer to semiconductor nanoparticles were studied using time-resolved femtosecond absorption spectroscopy. We found that excitation of the red wing of the absorption spectrum of the sensitizer populates the (3)MLCT state directly, both in solution and attached on semiconductor nanoparticle films. Electron injection is slowed down and becomes gradually less efficient as excitation moves towards red from the absorption maximum at 535 nm. At 675 nm the injection is non-exponential and characterized by 5, 30 and 180 ps time constants. The non-exponential electron injection observed is assigned to injection from a…
UV photoexcitation of a dissolved metalloid Ge9 cluster compound and its extensive ultrafast response.
2015
Femtosecond pump-probe absorption spectroscopy in tetrahydrofuran solution has been used to investigate the dynamics of a metalloid cluster compound {Ge9[Si(SiMe3)3]3}(-). Upon UV photoexcitation, the transients in the near-infrared spectral region showed signatures reminiscent of excess electrons in THF (bound or quasi-free) whereas in the visible part excited state dynamics of the cluster complex dominates.
Acs mugurējās daļas izmaiņas pēc ķirurģiskās kataraktas operācijas ar femtolāzeru, salīdzinot ar ultraskaņas fakoemulsifikāciju
2016
Diplomdarbs ir uzrakstīts latviešu valodā uz 32 lapām, satur 18 attēlus, 1 tabulu, 2 pielikumus un 27 atsauces uz literatūras avotiem. Pētījuma mērķis: Novērot un salīdzināt kādas ir acs ābola mugurējās daļas izmaiņas pēc kataraktas operācijas ar femtolāzeru un ultraskaņu, kā arī salīdzināt abus operācijas veidus, lai turpmāk sniegtu pacientiem informāciju par riskiem un ieguvumiem. Metode: Tika pētīti 40 pacienti, no kuriem 20 tika veikta ultraskaņas fakoemulsifikācija un 20, kuriem tika veikta femtosekunžu lāzera (FSL) operācija. Jaunākais pētījuma grupas pacients bija 43 gadus vecs un vecākais 88 gadus vecs. Vidējais vecums 66,57 gadi. Rezultāti: Pēc US fakoemulsifikācijas komplikāciju s…
Obligāciju emisija un ilgtermiņa aizņēmumi kā kapitāla piesaistes formas
2018
Darbā «Obligāciju emisija un ilgtermiņa aizņēmumi kā kapitāla piesaistes formas» tiek izpētītas uzņēmuma ārējās finansēšanas, kas tiek veikta ar mērķi palielināt uzņēmuma kapitālu, dažādās metodes. Aplūkojot mūsdienu ekonomiskās problēmas, var nonākt pie secinājuma, ka daudzi uzņēmumi piedzīvo ievērojamus finansiālos sarežģījumus. Šī iemesla pēc tādu ārējās finansēšanas avotu kā obligāciju emisija vai bankas kredīta noformēšanas izpēte – tā ir interesanta tēma, kura var būt lietderīga gan vidējiem, gan arī lieliem uzņēmumiem. Turklāt analīzes veikšanas procesā varēs izdarīt secinājumu par to, kāds lēmums uzņēmumam ir izdevīgāks – veikt obligāciju emisiju vai vērsties bankā ar nolūku saņemt …
Brīvā griba un iepriekšnolemtība islāma teoloģijā: mutazilīti un ašarīti
2017
Maģistra darbā tiek aplūkots brīvās gribas un iepriekšnolemtības koncepts no mutazilītu un ašarītu teoloģisko skolu skatupunkta. Pētījuma mērķi ir noskaidrot mutazilītu un ašarītu skolu vēsturisko izcelsmi, attīstību un faktorus, kas to ietekmējuši, kā arī šo skolu galvenos teoloģiskos un filozofiskos pamatprincipus, lai izprastu viņu nostāju atiecībā par brīvo gribu un iepriekšnolemtību islāma teoloģijā, kā arī aplūkot al-Kindi un al-Gazālī teoloģisko un filozofisko skatījumu. Izvirzīto mērķu sasniegšanai izmantota klasisko islāma tekstu – Korāna un Sunnas analīze, galvenokārt pievēršoties reliģisko pamatprincipu interpretācijām un iespējamajiem pamatojumiem, kā arī salīdzinošā un vēsturis…