Integrated structure for a resonant micro-gyroscope and accelerometer

This paper presents the study of the mechanical behavior of a microstructure designed to detect acceleration and angular velocity simultaneously. The new resonant micro-sensor proposed, fabricated by the ThELMA© surface-micromachining technique, bases detection of two components of external acceleration (one in-plane component and one out-of plane component) and two components of angular velocity (roll and yaw) on the variation of frequency of several elements set in resonance. The device, despite its small dimensions, provides a differential decoupled detection of four external quantities thanks to the presence of four slender beams resonating in bending and four torsional resonators

Integrated structure for a resonant micro-gyroscope and accelerometer

This paper presents the study of the mechanical behavior of a microstructure designed to detect acceleration and angular velocity simultaneously. The new resonant micro-sensor proposed, fabricated by the ThELMA© surface-micromachining technique, bases detection of two components of external acceleration (one in-plane component and one out-of plane component) and two components of angular velocity (roll and yaw) on the variation of frequency of several elements set in resonance. The device, despite its small dimensions, provides a differential decoupled detection of four external quantities thanks to the presence of four slender beams resonating in bending and four torsional resonators

The first Italian Superconducting Fault Current Limiter: Results of the field testing experience after one year operation

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Sub-10 μHz/ √ Hz measurement instrumentation for 140-dB DR frequency-modulated MEMS sensors

The field of frequency modulated (FM) microelectromechanical system (MEMS) sensors is emerging as an alternative to conventional amplitude modulated (AM) architectures, especially because of new applications requirements on extended full-scale and low noise, which turn into a wide dynamic range (DR). As a consequence, a need for characterization tools dedicated to this novel class of transducers is arising. This work presents the development of the key building blocks of an instrument for the characterization of FM sensors, including an integrated circuit and external board-level components. In the instrument design, the focus is set on versatility in terms of input range frequencies and on guaranteeing a dynamic range in the order of 140 dB. The instrument core is based on a frequency to digital converter, implemented through a type-II phase-locked-loop with a differentiator implementing a period meter. Low quantization noise is obtained using a high frequency (100 MHz) time reference, while versatility is guaranteed at the same time by having programmable parameters within the integrated circuit. The instrument is tested across the 27 kHz to 260 kHz input range and demonstrates sub-10 μHz/ √Hz frequency noise density in the range from 10 Hz to 100 Hz offset from the carrier and up to 100-Hz full scale. The instrument is available for testing and use to whoever is interested in its features

Tumor-induced expansion of regulatory T cells by conversion of CD4(+)CD25(-) lymphocytes is thymus and proliferation independent

The CD25(-) and CD25(+) CD4 T-lymphocyte compartments are tightly regulated. We show here that tumors break such balance, increasing the number of CD4(+)CD25(+) T cells in draining lymph node and spleen but not contralateral node of tumor-bearing mice. Tumor injection in thymectomized and CD25-depleted mice shows that CD4(+)CD25(+) T-cell expansion occurs even in the absence of the thymus and independently from proliferation of preexisting CD25(+) T cells. These newly generated cells are bona fide regulatory T cells (T reg) in terms of Foxp3 expression and suppression of CD3-stimulated or allogeneic effector cell proliferation. Transfer of congenic Thy1.1 CD4(+)CD25(-) T cells, from mice treated or not with vinblastine, into tumor-bearing or tumor-free mice and analysis of recovered donor lymphocytes indicate that conversion is the main mechanism for acquiring the expression of CD25 and Foxp3 through a process that does not require proliferation. Although conversion of CD4(+)CD25(-) T cells for generation of T regs has been described as a natural process that maintains peripheral T-reg population, this process is used by the tumor for immune escape. The prompt recovery of T regs from monoclonal antibody-mediated CD25 depletion in tumor-bearing mice suggests attempts able to inactivate rather than deplete them when treating existing tumors