Assessment of the stability of mephedrone in ante-mortem and post-mortem blood specimens

Aims The aim of this work is to test the stability of mephedrone added to whole blood collected from alive and dead mephedrone free-users and stored at three different temperatures (−20, +4 and +20 °C) with and without preservatives up to 6 months, trying to establish the best storage condition in order to reduce possible analyte loss/degradation during the storage period. Materials and methods Different sources of blood were obtained as follow: 10 samples of blood came from 10 alive mephedrone free-users (mean age 34 ± 15.8 years old) (Group 1), whereas 10 post mortem blood samples were obtained from 10 cadavers, in which the post mortem interval was between 24 and 36 h (Group 2). The cause of death in post mortem cases (mean age 45 ± 14.2 years old) was not drug related. Pools of blood were spiked with mephedrone at the concentration of 1 mg/L and 1 mL aliquots were transferred in 2 mL Eppendorf capped tubes with and without preservatives as follow: with ethylenediaminetetraacetic acid (EDTA) 3%; with sodium fluoride/potassium oxalate (NaF/KOx) 1.67%/0.2%, respectively; without preservatives. All samples were stored at three different temperatures: −20 °C, 4 °C and 20 °C and extracted and analyzed in duplicate by GC–MS according to a previously published method by Dickson et al., every other day during the first month and then weekly up to 6 months. Results and conclusions our study allow us to affirm that −20 °C is the best storage temperature for mephedrone stability in ante-mortem and post-mortem blood samples in comparison to the other two tested temperatures (+4 and +20 °C), showing higher values in both groups in samples stored with and without preservatives (p < 0.0001). The comparison of Group 1 (samples coming from alive subjects) and Group 2 (post-mortem samples) highlights a better stability of mephedrone in Group 1 (p < 0.001) at all tested storage conditions. Finally, the analysis of blood specimens stored with and without preservatives in both groups suggests that specimens stored with NaF/KOx maintain mephedrone stability better than those stored with EDTA (p < 0.001) and those stored without preservatives (p < 0.0001), therefore, we strongly recommend in order to maintain the highest mephedrone stability in blood, to store specimens at −20 °C adding NaF/KOx as preservative

Stability of endogenous GHB in vitreous humor vs peripheral blood in dead bodies

For the first time, the stability of GHB was tested in post-mortem peripheral blood and vitreous humor samples, collected from 22 dead bodies at two different times: at the external body examination at the place of death and then during autopsy. An ad hoc method for the detection and quantification of GHB in vitreous humor by gas chromatography coupled to mass spectrometry (GC-MS) was developed and validated, with a good linearity between 0.1 and 50μg/mL (r2=0.991) and a precision and accuracy always better than 10% and an analytical recovery higher than 90%. The geometric mean of GHB concentration in the 22 peripheral blood samples at t0 was: 3.6μg/mL (95% CI: 2.3-5.9μg/mL) and at t1 it was 7.4μg/mL (95% CI: 5.0-10.9μg/mL); that of GHB in the 22 vitreous humor at t0 was: 2.5μg/mL (95% CI: 1.5-4.1μg/mL) and at t1 it was 3.0μg/mL (95% CI: 1.9-4.8μg/mL). There was no significant difference between the GHB concentrations in vitreous humor and peripheral blood at t0 in all the samples (p>0.10). Conversely at t1, the increase of GHB in the peripheral blood was significantly increased by a 102% (range: 86-120%) (p0.05 vs t0). Finally at t1, GHB values in the two matrices were statistically different, being that of peripheral blood higher (p<0.01). This study demonstrated the usefulness of vitreous humor as a more stable alternative matrix in comparison to peripheral blood for the post-mortem determination of endogenous GHB

Highly Integrated Wideband Transmit/Receive Module for X-Band SAR Applications

The roadmaps of satellite-based synthetic aperture radar (SAR) systems show a trend that requires a continuous improvement of the active antenna in terms of operating bandwidth, scanning angle capability, and swath width, thus leading to the demand for increased RF power and better power efficiency of the RF transmitter. Moreover, compact size and light weight are relevant objectives for making the overall SAR instrument appealing for future applications. The transmit/receive module (TRM) shown in this paper was developed while combining all these requirements in a cost-effective approach. A careful design of all relevant RF interconnects and passive devices was performed to ensure the largest output power from the last high-power amplifier of the transmitting chain, the lowest noise figure at the input of the receiving chain, and the calibration capability for appropriately tuning the TX and RX signal. The TRM was manufactured and experimentally tested to verify its performances. The measurement results show the superior performances of the proposed compact high-power large-bandwidth TRM. The achieved target objectives make the design of the proposed TRM readily applicable for the development of a compact, high-power, and highly integrated AESAs to be used for next-generation satellite constellations for Earth observation

A low contact-resistance winged-bridge RF-MEMS series switch for wide-band applications

A MEMS ohmic series switch with a winged bridge has been designed, fabricated and tested. Based on the analysis of the various factors affecting the contact resistance of the switch, a new geometry has been adopted for the bridge, which involves the presence of two side wings and an appropriate number of bumps. An accurate electromagnetic analysis has been employed to identify a proper layout to reduce the losses due to bias lines and internal mismatch. In this manner, an on-state return loss better than 25 dB along with an off-state isolation better than 20 dB in the frequency range 0-30 GHz has been demonstrated. In reliability and power handling tests the switches have been actuated up to 108 cycles without any performance degradation and up to 109 cycles with an increase of 0.6 dB in the insertion loss (RF cold switching). Power handling tests have also been performed up to an input power of 5 W, showing a very linear Pout/Pin response and no stiction or failure due to other mechanisms of the MEMS switch

Development of High Con Coff Ratio RF MEMS Shunt Switches

Abstract. This paper reports on the successive improvements introduced in the shunt switches fabricated with the RF MEMS multiuser technology platform available at FBK. In the course of a multiyear development several technological features and design methods have been made available to enhance the operation of capacitive switches. This work analyzes their effects by reviewing the behaviour of the FBK capacitive switches at three different stages of this optimization process. Improvements have been assessed by means of DC electromechanical characterizations, which use a simple quasistatic C-V measurement to extract the switch actuation voltage and the capacitance in the on and off states (Con and Coff) and RF measurements. The addition of a floating metal layer into the process fow has allowed a great increase of the switch on state capacitances, getting Con/Coff ratios of 200, up to 50 times greater than the ones obtained for the same structures without this feature

Technological and design improvements for RF MEMS shunt switsches

This paper reports on the successive improvements introduced in the shunt switches fabricated with the RF MEMS multiuser technology platform available at FBK-irst. In the course of a multiyear development several technological features and design methods have been made available to enhance the operation of capacitive switches. This work analyzes their effects by reviewing the behaviour of the FBK-irst capacitive switches at three different stages of this optimization process. Improvements have been assessed by means of DC electromechanical characterizations, which use a simple quasistatic C-V measurement to extract the switch actuation voltage and the capacitance in the on and off states (Con and Coff) and RF measurements. The addition of a floating metal layer into the process flow has allowed a great increase of the switch on state capacitances, getting Con/Coff ratios of 200, up to 50 times greater than the ones obtained for the same structures without this feature

The liquid argon TPC for the ICARUS experiment

The ICARUS project aims at the realisation of a large liquid argon TPC to be run at the Underground Laboratories of Gran Sasso in Italy. An intense R&D; activity has put on firm grounds this new detector technology and experimentally confirmed its feasibility on a few ton scale. Based on these solid achievements, the collaboration is now confident of being able to build and safely operate a multi-kton detector. The reseach program of the experiment involves the systematic study of a wide spectrum of physical phenomena covering many orders of magnitude in the energy deposited in the detector: from the few MeV of solar neutrino interactions, to the about one GeV of the proton decay and atmospheric neutrinos, up to the higher energies of neutrinos from accelerators