GNC architecture solutions for robust operations of a free-floating space manipulator via image based visual servoing

On-orbit servicing often requires the use of robotic arms, and a key asset in this kind of operations is autonomy. In this framework, the use of optical devices is a solution, already analyzed in many researches both for autonomous rendezvous and docking and for the evaluation of the control of the manipulator. In the present paper, simulations for assessing the controller performance are realized in a high-fidelity purposely developed software architecture, in which not only the selected 6 DOF space manipulator is modeled, but also a virtual camera, acquiring in the loop images of the target CAD model imported, is included in the GNC loop. This approach allows to emphasis several problems that would not emerge in simulations with images characterized by easily-identifiable, purposely-created markers. At the scope, a specific GNC architecture is developed, based on finite-state machine logic. According to this approach, two different Image Based Visual Servoing strategies are alternatively performed, commanding only linear or angular velocity of the camera, switching between the two control techniques when the “stack” or “divergence” condition is triggered. In this way a stable and robust accomplishment of the tasks is achieved for many configurations and for different target models

Testing Dissipative Collapse Models with a Levitated Micromagnet

We present experimental tests of dissipative extensions of spontaneous wave function collapse models based on a levitated micromagnet with ultralow dissipation. The spherical micromagnet, with radius $R=27$ $\mu$m, is levitated by Meissner effect in a lead trap at $4.2$ K and its motion is detected by a SQUID. We perform accurate ringdown measurements on the vertical translational mode with frequency $57$ Hz, and infer the residual damping at vanishing pressure $\gamma/2\pi<9$ $\mu$Hz. From this upper limit we derive improved bounds on the dissipative versions of the CSL (continuous spontaneous localization) and the DP (Di\'{o}si-Penrose) models with proper choices of the reference mass. In particular, dissipative models give rise to an intrinsic damping of an isolated system with the effect parameterized by a temperature constant; the dissipative CSL model with temperatures below 1 nK is ruled out, while the dissipative DP model is excluded for temperatures below $10^{-13}$ K. Furthermore, we present the first bounds on dissipative effects in a more recent model, which relates the wave function collapse to fluctuations of a generalized complex-valued spacetime metric.Comment: 10 pages, 7 figure

Age-Related Differences in Cortical Activity during a Visuo-Spatial Working Memory Task with Facial Stimuli

Emotion, importantly displayed by facial expressions, is one of the most significant memory modulators. The interaction between memory and the different emotional valences change across lifespan, while young adults (YA) are expected to better recall negative events (Negativity Bias Hypothesis), older adults (OA) tend to focus on positive stimuli (Positivity Effect Hypothesis). This research work aims at verifying whether cortical electrical activity of these two age groups would also be differently influenced by emotional valences in a visuo-spatial working memory task. 27 YA (13 males) and 25 OA (14 males), all healthy volunteers, underwent electroencephalographic recordings (21 scalp electrodes montage), while performing the Spatial Delayed Recognition Span Task using a touch screen with different stimuli categories: neutral, positive and negative faces and geometric pictures. YA obtained higher scores than OA, and showed higher activation of theta and alpha bands in the frontal and midline regions, besides a more evident right-hemispheric asymmetry on alpha band when compared to OA. For both age groups, performance in the task was worse for positive faces than to negative and to neutral faces. Facial stimuli induced a better performance and higher alpha activation on the pre-frontal region for YA, and on the midline, occipital and left temporal regions for OA when compared to geometric figures. The superior performance of YA was expected due to the natural cognitive deficits connected to ageing, as was a better performance with facial stimuli due to the evolutionary importance of faces. These results were related to cortical activity on areas of importance for action-planning, decision making and sustained attention. Taken together, they are in accordance with the Negativity Bias but do not support the Positivity Effect. The methodology used was able to identify age-related differences in cortical activity during emotional mnemonic processing and may be interesting to future investigations

Advances in the development of entry inhibitors for sialic-acid-targeting viruses

Over the past decades, several antiviral drugs have been developed to treat a range of infections. Yet the number of treatable viral infections is still limited, and resistance to current drug regimens is an ever-growing problem. Therefore, additional strategies are needed to provide a rapid cure for infected individuals. An interesting target for antiviral drugs is the process of viral attachment and entry into the cell. Although most viruses use distinct host receptors for attachment to the target cell, some viruses share receptors, of which sialic acids are a common example. This review aims to give an update on entry inhibitors for a range of sialic-acidtargeting viruses and provides insight into the prospects for those with broad-spectrum potential

An antiviral trap made of protein nanofibrils and iron oxyhydroxide nanoparticles

Minimizing the spread of viruses in the environment is the first defence line when fighting outbreaks and pandemics, but the current COVID-19 pandemic demonstrates how difficult this is on a global scale, particularly in a sustainable and environmentally friendly way. Here we introduce and develop a sustainable and biodegradable antiviral filtration membrane composed of amyloid nanofibrils made from food-grade milk proteins and iron oxyhydroxide nanoparticles synthesized in situ from iron salts by simple pH tuning. Thus, all the membrane components are made of environmentally friendly, non-toxic and widely available materials. The membrane has outstanding efficacy against a broad range of viruses, which include enveloped, non-enveloped, airborne and waterborne viruses, such as SARS-CoV-2, H1N1 (the influenza A virus strain responsible for the swine flu pandemic in 2009) and enterovirus 71 (a non-enveloped virus resistant to harsh conditions, such as highly acidic pH), which highlights a possible role in fighting the current and future viral outbreaks and pandemics

EFFECTS OF EMOTIONAL CONTENT ON DECLARATIVE MEMORY: TWO STUDIES CONDUCTED ON HEALTHY SUBJECTS AND CEPHALALGIC PATIENTS

RESUMEN Varios estudios sugieren que el despertar emocional puede promover el almacenamiento de información en la memoria. Nosotros reportamos dos estudios evaluando los efectos del contenido emocional sobre la memoria declarativa, efectuados con sujetos sanos y pacientes cefalálgicos. Utilizamos una adaptación de dos versiones del mismo relato, con diferentes propiedades (neutral o emocional), la cual ha sido previamente empleada en experimentos que abordan los efectos de mejoría sobre la retención de la memoria causados por las emociones. En el primer estudio, efectuado en estudiantes sanos, empleamos potenciales relacionados a eventos (PRE) para evaluar si existe una lateralización hemisférica relacionada al sexo, de los potenciales eléctricos producidos por el contenido emocional de un relato. Comparamos las ondas P300 de los hemisferios izquierdo y derecho, registrados en los sitios correspondientes a los electrodos P3 y P4, en respuesta a estímulos neutrales o emocionales en hombres y mujeres. Los estímulos emocionales produjeron un P300 mayor, medido tanto por la amplitud como por la latencia del potencial, en el hemisferio izquierdo de mujeres comparado con el de los hombres, sin embargo, produjeron un P300 mayor en el hemisferio derecho en los hombres comparado con el de las mujeres. La mejoría en la memoria, originada por el contenido emocional de la información, puede estar relacionada con el diferencial del componente P300 durante la codificación. Estos datos indican que tanto el sexo como la lateralización hemisférica constituyen importantes factores que interactúan para influenciar tanto a los correlatos neurales de las emociones como a la memoria influenciada emocionalmente.En el segundo estudio evaluamos la influencia del mismo estímulo emocional, utilizado en el primer estudio, sobre la memoria declarativa de pacientes cefalálgicos, que padecen migraña, divididos en dos grupos: migrañosos sin ningún tratamiento y migrañosos tratados con el antidepresivo amitriptilina. No se efectúo análisis de los PRE en esta parte de la investigación. Los hallazgos del presente experimento sugieren que la migraña crónica es asociada con deterioros en la memoria. Considerando que la migraña se asocia con depresión mayor, la presente investigación evaluó también el efecto del antidepresivo amitriptilina. Nuestros resultados mostraron que la amitriptilina tiene un efecto dañino sobre la memoria. De hecho, en nuestro estudio los migrañosos sin tratamiento recordaron la parte más emotiva del relato, de manera significativamente mejor comparados con los migrañosos tratados con amitriptilina. Por lo tanto, nuestros datos sugieren que la amitriptilina bloquea los efectos de mejoría sobre el procesamiento de la memoria causados por el contenido emocional de la información. Palabras clave: Memoria emocional, potenciales relacionados a eventos, componente P300, migraña, amitriptilina. ABSTRACT Several studies suggest that emotional arousal can promote memory storage. We report two studies evaluating the effects of emotional content on declarative memory, conducted with healthy subjects and cephalgic patients. We utilized an adaptation of two versions of the same story, with different arousing properties (neutral or emotional), which have been already employed in experiments involving the enhancing effects of emotions on memory retention. In the first study, conducted on healthy students, we used event related potentials (ERP) to evaluate whether there is a sex-related hemispheric lateralization of electrical potentials elicited by the emotional content of a story. We compared left and right hemisphere P300 waves, recorded in P3 and P4 electrode sites, in response to emotional or neutral stimuli in men and women. In the left hemisphere, emotional stimuli elicited a stronger P300 in women, compared to men, as indexed by both amplitude and latency measures; moreover, the emotional content of the story elicited a stronger P300 in the right hemisphere in men than in women. The better memory for the arousal material may be related to the differential P300 at encoding. These data indicate that both sex and cerebral hemisphere constitute important, interacting influences on neural correlates of emotion, and of emotionally influenced memory.In the second study we evaluated the influence of the same emotional stimuli, utilized in the first study, on declarative memory on cephalalgic patients, suffering from migraine headache, divided in 2 groups: migraineurs without any treatment and migraineurs treated with the antidepressant amitriptyline. No ERP analysis was performed in this part of research. The findings of the present experiments suggest that chronic migraine is associated with memory impairment. Taking into account that migraine is associated with major depression, in the present research the effect of the antidepressant amitriptyline was also evaluated. Our results showed that amitriptyline has an impairment effect on memory. In fact, in our study the untreated migraineurs recalled the most emotional phase of the arousal story significantly better compared to migraineurs treated with amitriptyline. Then, our data suggest that amitriptyline prevents the enhancing effects of emotional content on memory processes. Key words: emotional memory, event related potentials, P300 wave, migraine, amitriptyline

EFFECTS OF EMOTIONAL CONTENT ON DECLARATIVE MEMORY: TWO STUDIES CONDUCTED ON HEALTHY SUBJECTS AND CEPHALALGIC PATIENTS

RESUMEN Varios estudios sugieren que el despertar emocional puede promover el almacenamiento de información en la memoria. Nosotros reportamos dos estudios evaluando los efectos del contenido emocional sobre la memoria declarativa, efectuados con sujetos sanos y pacientes cefalálgicos. Utilizamos una adaptación de dos versiones del mismo relato, con diferentes propiedades (neutral o emocional), la cual ha sido previamente empleada en experimentos que abordan los efectos de mejoría sobre la retención de la memoria causados por las emociones. En el primer estudio, efectuado en estudiantes sanos, empleamos potenciales relacionados a eventos (PRE) para evaluar si existe una lateralización hemisférica relacionada al sexo, de los potenciales eléctricos producidos por el contenido emocional de un relato. Comparamos las ondas P300 de los hemisferios izquierdo y derecho, registrados en los sitios correspondientes a los electrodos P3 y P4, en respuesta a estímulos neutrales o emocionales en hombres y mujeres. Los estímulos emocionales produjeron un P300 mayor, medido tanto por la amplitud como por la latencia del potencial, en el hemisferio izquierdo de mujeres comparado con el de los hombres, sin embargo, produjeron un P300 mayor en el hemisferio derecho en los hombres comparado con el de las mujeres. La mejoría en la memoria, originada por el contenido emocional de la información, puede estar relacionada con el diferencial del componente P300 durante la codificación. Estos datos indican que tanto el sexo como la lateralización hemisférica constituyen importantes factores que interactúan para influenciar tanto a los correlatos neurales de las emociones como a la memoria influenciada emocionalmente.En el segundo estudio evaluamos la influencia del mismo estímulo emocional, utilizado en el primer estudio, sobre la memoria declarativa de pacientes cefalálgicos, que padecen migraña, divididos en dos grupos: migrañosos sin ningún tratamiento y migrañosos tratados con el antidepresivo amitriptilina. No se efectúo análisis de los PRE en esta parte de la investigación. Los hallazgos del presente experimento sugieren que la migraña crónica es asociada con deterioros en la memoria. Considerando que la migraña se asocia con depresión mayor, la presente investigación evaluó también el efecto del antidepresivo amitriptilina. Nuestros resultados mostraron que la amitriptilina tiene un efecto dañino sobre la memoria. De hecho, en nuestro estudio los migrañosos sin tratamiento recordaron la parte más emotiva del relato, de manera significativamente mejor comparados con los migrañosos tratados con amitriptilina. Por lo tanto, nuestros datos sugieren que la amitriptilina bloquea los efectos de mejoría sobre el procesamiento de la memoria causados por el contenido emocional de la información. Palabras clave: Memoria emocional, potenciales relacionados a eventos, componente P300, migraña, amitriptilina. ABSTRACT Several studies suggest that emotional arousal can promote memory storage. We report two studies evaluating the effects of emotional content on declarative memory, conducted with healthy subjects and cephalgic patients. We utilized an adaptation of two versions of the same story, with different arousing properties (neutral or emotional), which have been already employed in experiments involving the enhancing effects of emotions on memory retention. In the first study, conducted on healthy students, we used event related potentials (ERP) to evaluate whether there is a sex-related hemispheric lateralization of electrical potentials elicited by the emotional content of a story. We compared left and right hemisphere P300 waves, recorded in P3 and P4 electrode sites, in response to emotional or neutral stimuli in men and women. In the left hemisphere, emotional stimuli elicited a stronger P300 in women, compared to men, as indexed by both amplitude and latency measures; moreover, the emotional content of the story elicited a stronger P300 in the right hemisphere in men than in women. The better memory for the arousal material may be related to the differential P300 at encoding. These data indicate that both sex and cerebral hemisphere constitute important, interacting influences on neural correlates of emotion, and of emotionally influenced memory.In the second study we evaluated the influence of the same emotional stimuli, utilized in the first study, on declarative memory on cephalalgic patients, suffering from migraine headache, divided in 2 groups: migraineurs without any treatment and migraineurs treated with the antidepressant amitriptyline. No ERP analysis was performed in this part of research. The findings of the present experiments suggest that chronic migraine is associated with memory impairment. Taking into account that migraine is associated with major depression, in the present research the effect of the antidepressant amitriptyline was also evaluated. Our results showed that amitriptyline has an impairment effect on memory. In fact, in our study the untreated migraineurs recalled the most emotional phase of the arousal story significantly better compared to migraineurs treated with amitriptyline. Then, our data suggest that amitriptyline prevents the enhancing effects of emotional content on memory processes. Key words: emotional memory, event related potentials, P300 wave, migraine, amitriptyline

Benzene with Alkyl Chains Is a Universal Scaffold for Multivalent Virucidal Antivirals.

Most viruses start their invasion by binding to glycoproteins' moieties on the cell surface (heparan sulfate proteoglycans [HSPG] or sialic acid [SA]). Antivirals mimicking these moieties multivalently are known as broad-spectrum multivalent entry inhibitors (MEI). Due to their reversible mechanism, efficacy is lost when concentrations fall below an inhibitory threshold. To overcome this limitation, we modify MEIs with hydrophobic arms rendering the inhibitory mechanism irreversible, i.e., preventing the efficacy loss upon dilution. However, all our HSPG-mimicking MEIs only showed reversible inhibition against HSPG-binding SARS-CoV-2. Here, we present a systematic investigation of a series of small molecules, all containing a core and multiple hydrophobic arms terminated with HSPG-mimicking moieties. We identify the ones that have irreversible inhibition against all viruses including SARS-CoV-2 and discuss their design principles. We show efficacy in vivo against SARS-CoV-2 in a Syrian hamster model through both intranasal instillation and aerosol inhalation in a therapeutic setting (12 h postinfection). We also show the utility of the presented design rules in producing SA-mimicking MEIs with irreversible inhibition against SA-binding influenza viruses