Artículos (Instituto de Microelectrónica de Sevilla (IMSE-CNM))
https://hdl.handle.net/11441/10969
2024-03-29T06:34:35ZElectrical pulse stimulation parameters modulate N2a neuronal differentiation
https://hdl.handle.net/11441/154962
Electrical pulse stimulation parameters modulate N2a neuronal differentiation
Electrical pulse stimulation has been used to enhance the differentiation or proliferation of neuronal progenitor cells in tissue engineering and cancer treatment. Therefore, a comprehensive investigation of the effects caused by its parameters is crucial for improvements in those fields. We propose a study of pulse parameters, to allow the control of N2a cell line fate and behavior. We have focused on designing an experimental setup that allows for the knowledge and control over the environment and the stimulation signals applied. To map the effects of the stimulation on N2a cells, their morphology and the cellular and molecular reactions induced by the pulse stimulation have been analyzed. Immunofluorescence, rt-PCR and western blot analysis have been carried out for this purpose, as well as cell counting. Our results show that low-amplitude electrical pulse stimulation promotes proliferation of N2a cells, whilst amplitudes in the range 250 mV/mm–500 mV/mm induce differentiation. Amplitudes higher than 750 mV/mm produce cell damage at low frequencies. For high frequencies, large amplitudes are needed to cause cell death. An inverse relation has been found between cell density and pulse-induced neuronal differentiation. The best condition for neuronal differentiation was found to be 500 mV/mm at 100 Hz. These findings have been confirmed by up-regulation of the Neurod1 gene. Our preliminary study of the molecular effects of electrical pulse stimulation on N2a offers premonitory clues of the PI3K/Akt/GSK-3β pathway implications on the neuronal differentiation process through ES. In general, we have successfully mapped the sensitivity of N2a cells to electrical pulse stimulation parameters.
2024-01-25T00:00:00ZOperation limits for RTD-based MOBILE circuits
https://hdl.handle.net/11441/153159
Operation limits for RTD-based MOBILE circuits
Resonant-tunneling-diode (RTD)-based monostable-bistable logic element (MOBILE) circuits operate properly in a certain frequency range. They exhibit both a minimum operating frequency and a maximum one. From a design point of view, it should be desirable to have gates with a correct operation from dc up to the maximum operating frequency (i.e., without the minimum bound). This paper undertakes this problem by analyzing how transistors and RTDs interact in RTD-based circuits. Two malfunctions have been identified: the incorrect evaluation of inputs and the lack of self-latching operation. The difficulty to study these problems in an analytical way has been overcome by resorting to series expansions for both the RTD and the heterojunction field-effect transistor I- V characteristics in the points of interest. We have obtained analytical expression linking representative device parameters and technological setup, for a MOBILE-based circuit to operate correctly.
2009-02-01T00:00:00ZEfficient realisation of MOS-NDR threshold logic gates
https://hdl.handle.net/11441/153087
Efficient realisation of MOS-NDR threshold logic gates
A novel realisation of inverted majority gates based on a programmable
MOS-NDR device is presented. A comparison, in terms of area
and power consumption, has been performed to demonstrate that the
proposed circuit is more efficient than a similar reported structure.
2009-11-05T00:00:00ZSecuring Minutia Cylinder Codes for Fingerprints through Physically Unclonable Functions: An Exploratory Study
https://hdl.handle.net/11441/153077
Securing Minutia Cylinder Codes for Fingerprints through Physically Unclonable Functions: An Exploratory Study
A number of personal devices, such as smartphones,
have incorporated fingerprint recognition solutions for user
authentication purposes. This work proposes a dual-factor
fingerprint matching scheme based on P-MCCs (Protected
Minutia Cylinder-Codes) generated from fingerprint images
and PUFs (Physically Unclonable Functions) generated from
device SRAMs (Static Random Access Memories). Combining
the fingerprint identifier with the device identifier results in a
secure template satisfying the discriminability, irreversibility,
revocability, and unlinkability properties, which are strongly
desired for data privacy and security. Experiments convey the
benefits of the proposed dual-factor authentication mechanism
in enhancing the security of personal devices that utilize
biometric authentication schemes.
2018-07-16T00:00:00Z