Caffeine. cognitive and physical performance enhancer or psychoactive drug?

Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine's mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine's interaction with other substances or to the individuals' preexisting metabolism alterations or diseases

Heroin-piracetam mixture: suggested mechanisms of action and risks of misinterpretation for drug users

Piracetam is a positive allosteric modulator of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor that has been frequently used in the treatment of cognitive disorders. Press and internet reports indicate that the use of piracetam, as a heroin adulterant, has spread rapidly in some countries, especially in Asia and Europe. Its use, as adulterant, is believed to produce more profound desirable effects, while decreasing hangover. Recent surveys demonstrated that piracetam protects neurons from heroin-induced apoptosis. The protective role of this adulterating substance may be related to restoration of beta-endorphin levels and to its neuroprotective effects. The aim of this paper is to review the relevant literature and suggest the main hypothetical mechanisms that justify its use as a heroin adulterant, try to understand if its use could help people who want to come off heroin by reducing withdrawal symptoms and, finally, give useful information that permit us to understand why drug trafficking organisations started to use piracetam as heroin adulterant

Results of the attitude reconstruction for the UniSat-6 microsatellite using in-orbit data

UniSat-6 is a civilian microsatellite that was launched in orbit on the 19th of June, 2014. Its main mission consisted in the in-orbit release of a number of on-board carried Cubesats and in the transmission to the UniSat-6 ground station of telemetry data and images from an on-board mounted camera. The spacecraft is equipped with a passive magnetic attitude control system. Gyros and magnetometers provide the information about the attitude of the spacecraft. The importance of reconstructing the attitude motion of UniSat-6 lies in the dual possibility, for future missions, of:controlling the direction of ejection of the on-board carried satelliteshaving an accurate pointing for remote sensing operation.The reconstruction of the attitude motion of UniSat-6 is based on the data of the on-board Commercial Off The Shelf (COTS) gyros and magnetometers, downloaded at the passages over the ground station in Roma, Italy. At ground, these data have been processed with the UnScented QUaternion Estimator (USQUE) algorithm. This estimator is an adaptation of the Unscented Filter to the problem of spacecraft attitude estimation. The USQUE is based on a dual attitude representation, which involves both quaternions and Generalized Rodrigues Parameters. In this work, the propagation phase of the algorithm contains only a kinematic model of the motion of the spacecraft. This paper presents the results of the reconstruction of the UniSat-6 attitude using on-board measurements. The results show that the spacecraft effectively stabilized its attitude motion thanks to the on-board magnetic devices

A proposed role for sepsis in the pathogenesis of myocardial calcification

Myocardial calcification is a rare and life-threatening condition that is a recognised complication of ischaemic heart disease, cardiac surgery, rheumatic fever and myocarditis. It is distinct from coronary artery or valvular calcification, and can be seen in patients with abnormal calcium metabolism1 . Its presence in the context of sepsis is less well recognised and the mechanisms responsible are poorly understood. We review the relevant literature and propose a mechanistic theory for its pathogenesi

Modeling a Satellite Mockup’s Angular Motion on an Air Bearing with Uniaxial Magnetic Attitude Control

© 2020, Pleiades Publishing, Ltd. Abstract: The angular motion of a mockup of a satellite’s attitude control system on an air bearing is considered. The general purpose of the work is to verify the one-axis magnetic attitude control algorithm. This control is designed to maintain the satellite’s solar panels attitude towards the Sun. Specific mockup motion patterns are found. These patterns allow comparing the ground-based control performance results and its expected inflight operation. Asymptotically stable precession and near planar motion are outlined. Mathematical modelling is performed for these patterns. Their applicability for the laboratory experiments is shown

CubeSat constellations for disaster management in remote areas

In recent years, CubeSats have considerably extended their range of possible applications, from a low cost means to train students and young researchers in space related activities up to possible complementary solutions to larger missions. Increasingly popular, whereas CubeSats are still not a solution for all types of missions, they offer the possibility of performing ambitious scientific experiments. Especially worth considering is the possibility of performing Distributed Space Missions, in which CubeSat systems can be used to increase observation sampling rates and resolutions, as well as to perform tasks that a single satellite is unable to handle. The cost of access to space for traditional Earth Observation (EO) missions is still quite high. Efficient architecture design would allow reducing mission costs by employing CubeSat systems, while maintaining a level of performance that, for some applications, could be close to that provided by larger platforms, and decreasing the time needed to design and deploy a fully functional constellation. For these reasons many countries, including developing nations, agencies and organizations are looking to CubeSat platforms to access space cheaply with, potentially, tens of remote sensing satellites. During disaster management, real-time, fast and continuous information broadcast is a fundamental requirement. In this sense, a constellation of small satellites can considerably decrease the revisit time (defined as the time elapsed between two consecutive observations of the same point on Earth by a satellite) over remote areas, by increasing the number of spacecraft properly distributed in orbit. This allows collecting as much data as possible for the use by Disaster Management Centers. This paper describes the characteristics of a constellation of CubeSats built to enable access over the most remote regions of Brazil, supporting an integrated system for mitigating environmental disasters in an attempt to prevent the catastrophic effects of natural events such as heavy rains that cause flooding. In particular, the paper defines the number of CubeSats and the orbital planes required to minimize the revisit time, depending on the application that is the mission objective. Each CubeSat is equipped with the suitable payloads and possesses the autonomy and pointing capabilities needed to meet the mission requirements. Thanks to the orbital features of the constellation, this service could be exploited by other tropical countries. Coverage of other areas of the Earth might be provided by adjusting the number and in-orbit distribution of the spacecraft

Experimental and Numerical Evaluation of the NPSHR Curve of an Industrial Centrifugal Pump

Cavitation triggers harmful flow instabilities yielding both significant decrease of performance and reduced reliability. The aim of this paper is to investigate the accuracy of numerical methodologies for the correct prediction of cavitation inception in centrifugal pumps. Preliminary analyses are performed on the NACA 0009 hydrofoil using the ANSYS CFX V14.5 code. The available bubble dynamics model is calibrated using the experimental data in cavitation conditions. Then, the optimized parameters are used for the evaluation of the NPSHR curve of the R250 centrifugal pump industrial pump designed by WEIRGabbioneta srl. Reynolds-Averaged Navier-Stokes mono- and two-phase calculations are performed. The performance curve of the R250 centrifugal pump is evaluated at first, and then the NPSHR curve is obtained for the design flow rate. The control volume of the numerical analysis includes all the hydraulic features from flange to flange (except for the side chambers) and then a direct comparison with the available experimental data obtained during two experimental campaigns is possible. The numerical activity demonstrated that an adequately calibrated model is able to reproduce the shape of the cavitation curve of an industrial centrifugal pump, although the NPSHR value is underestimated

Tabletop Testbed for Attitude Determination and Control of Nanosatellites

To simulate the conditions of the space environment at ground, the Laboratory of Application and Innovation in Aerospace Science (LAICA) of the University of Brasília (UnB) is developing a dedicated testbed to reproducing nanosatellite attitude motion. The testbed is composed of an air-bearing table and a Helmholtz cage. The air-bearing table is a spacecraft simulator that can simulate frictionless conditions with three rotational degrees of freedom. Balancing the simulator is essential in order to make the gravitational torque negligible. The testbed is also equipped with a Helmholtz cage to recreate the Earth's magnetic field conditions that spacecrafts encounter in orbit. This paper presents the design and realization of this low-cost testbed. A simple and efficient automated balancing algorithm based on the least-squares method (LSM) is proposed and validated by experiments. The performance of the proposed simulator is evaluated and compared with previous works

Helmholtz cage design and validation for nanosatellites HWIL testing

This paper deals with the design, realization and testing of an Earth magnetic field simulator, that allows to validate hardware in the loop algorithms, as well as to test new actuators. The design is driven by typical small satellites functional requirements. The subsystems that compose the simulator are described in detail. The validation of the simulator is performed by assessing its functioning, the uniformity of the recreated magnetic field and the functionality of a magnetorquer

Takotsubo cardiomyopathy and sepsis: a systematic review

Takotsubo cardiomyopathy (TTC) is characterized by a systolic dysfunction localized in the apical and medial aspect of the left ventricle. It is usually related to physical or emotional stress. Recent evidence highlighting the role of infection led us to analyze the links between TTC and sepsis. A systematic review of the literature was undertaken to assess any trends in clinical findings, diagnosis, and outcomes in such patients. We identified 23 selected papers reporting a total of 26 patients, having sepsis, in whom TTC occurred. For each case, we collected data identifying population characteristics, source of sepsis, clinical disease description, and the results of cardiovascular investigations. The majority of patients were females (n = 16), mean age was 62.8 (14.0 standard deviation) years, and clinical outcome was favorable in 92.3% of the cases once the management of sepsis was initiated. A better understanding of the mechanisms of sepsis-associated TTC may generate novel strategies to treat the complications of this cardiomyopathy and may even help predict and prevent its occurrence