Joana S. Paiva

Optical fiber tweezers have been gaining an important role in several applications in Biology and Medicine. Due to their outstanding focusing abilities, they are able to trap and manipulate microparticles including cells without physical contact and with a low degree of invasiveness. Recently, we proposed a fiber tweezer configuration based on a polymeric micro-lens on the top of a single mode fiber, obtained by a self-guided photopolymerization process, able to simultaneously trap and identify… Mehr anzeigen

Optical fiber tweezers have been gaining an important role in several applications in Biology and Medicine. Due to their outstanding focusing abilities, they are able to trap and manipulate microparticles including cells without physical contact and with a low degree of invasiveness. Recently, we proposed a fiber tweezer configuration based on a polymeric micro-lens on the top of a single mode fiber, obtained by a self-guided photopolymerization process, able to simultaneously trap and identify the trapped target through short-term portions of the back-scattered signal. In this paper, we propose a variant of this fabrication method, capable of producing more robust fiber tips, which produce stronger trapping effects on targets by as much as two to ten fold, while guaranteeing a successful distinction between the different classes of trapped particles. This novel fabrication method consists in the introduction of a multi mode fiber section on the tip of a single mode (SM) fiber. A detailed description of how relevant fabrication parameters such as the length of the multi mode section and the photopolymerization laser power can be tuned for different purposes (e.g., microparticles trapping only, simultaneous trapping and sensing) is also provided, based on both experimental and theoretical evidences. Weniger anzeigen

https://doi.org/10.1117/12.2304358

Recent trends on microbiology point out the urge to develop optical micro-tools with multifunctionalities such as simultaneous manipulation and sensing. Considering that miniaturization has been recognized as one of the most important paradigms of emerging sensing biotechnologies, optical fiber tools, including Optical Fiber Tweezers (OFTs), are suitable candidates for developing multifunctional small sensors for Medicine and Biology. OFTs are flexible and versatile optotools based on fibers… Mehr anzeigen

Recent trends on microbiology point out the urge to develop optical micro-tools with multifunctionalities such as simultaneous manipulation and sensing. Considering that miniaturization has been recognized as one of the most important paradigms of emerging sensing biotechnologies, optical fiber tools, including Optical Fiber Tweezers (OFTs), are suitable candidates for developing multifunctional small sensors for Medicine and Biology. OFTs are flexible and versatile optotools based on fibers with one extremity patterned to form a micro-lens. These are able to focus laser beams and exert forces onto microparticles strong enough (piconewtons) to trap and manipulate them. In this paper, through an exploratory analysis of a 45 features set, including time and frequency-domain parameters of the back-scattered signal of particles trapped by a polymeric lens, we created a novel single feature able to differentiate synthetic particles (PMMA and Polystyrene) from living yeasts cells. This single statistical feature can be useful for the development of label-free hybrid optical fiber sensors with applications in infectious diseases detection or cells sorting. It can also contribute, by revealing the most significant information that can be extracted from the scattered signal, to the development of a simpler method for particles characterization (in terms of composition, heterogeneity degree) than existent technologies. Weniger anzeigen

Oral Presentation

DOI: 10.1371/journal.pone.0180942

DOI: 10.1109/ENBENG.2017.7889447

DOI: 10.3389/fnhum.2016.00200

DOI: 10.1109/IS.2016.7737447

Attention is defined as the maintenance of stable goal-directed behaviour during task
performance. However, attention levels fluctuate with time due to internal (brain-driven)
or external (stimulus-driven) events. The consequences of those fluctuations can be fairly
benign such as not detecting a certain external stimuli; whereas in specific contexts, as
driving scenarios or hazard situations, they can lead to tragedies. Notably, the detection
of lapses in attention even before… Mehr anzeigen

Attention is defined as the maintenance of stable goal-directed behaviour during task
performance. However, attention levels fluctuate with time due to internal (brain-driven)
or external (stimulus-driven) events. The consequences of those fluctuations can be fairly
benign such as not detecting a certain external stimuli; whereas in specific contexts, as
driving scenarios or hazard situations, they can lead to tragedies. Notably, the detection
of lapses in attention even before these happen, could avoid catastrophic consequences. The aim of this work
was to determine if these parameters could be used for predicting attention lapses. Twenty young healthy adults were recruited for this study. EEG signals and eye activity
patterns were acquired during performance of a choice reaction time task. The findings of this study showed that beta and gamma EEG phase coherence measures
were capable of predicting fluctuations in subject’s attention levels, i.e. intraindividual
differences in reaction time. Increased frontal-parietal prestimulus phase coherence
in beta and gamma frequency bands was associated with faster responses to stimulus’
presentation, emphasizing the role of the attentional frontal-parietal networks for the
maintenance of attention levels. In contrast, posterior alpha amplitude was not related to
differences in RT. Pupil dilation was found to be a reliable pattern to predict fluctuations
in subject’s attention levels, while gaze position measures were not capable of predicting
those fluctuations. Relatively to the classification platform developed, only the unimodal classifiers based
on eye activity parameters ensured a classification rate above chance level.
In conclusion, this study revealed that fronto-parietal EEG phase coherence and pupil
diameter are related to moment-to-moment fluctuations in attention. Eye parameters were
found to be useful to predict on a trial-by-trial basis the subject’s attention level. Weniger anzeigen

DOI 10.1007/s11517-015-1393-5

Approximately 59 hours of ECG missions recordings of 5 Firefighters in .bdd files.

DOI: 10.1109/EMBC.2016.7591452