Quantum phase slips in superconducting Nb nanowire networks deposited on self-assembled Si templates

Robust porous silicon substrates were employed for generating interconnected networks of superconducting ultrathin Nb nanowires. Scanning electron microscopy analysis was performed to investigate the morphology of the samples, which constitute of polycrystalline single wires with grain size of about 10 nm. The samples exhibit nonzero resistance over a broad temperature range below the critical temperature, fingerprint of phase slippage processes. The transport data are satisfactory reproduced by models describing both thermal and quantum fluctuations of the superconducting order parameter in thin homogeneous superconducting wires.Comment: accepted for publication on Applied Physics Letter

Dysfunctional play and dopamine physiology in the Fischer 344 rat

Juvenile Fischer 344 rats are known to be less playful than other inbred strains, although the neurobiological substrate(s) responsible for this phenotype is uncertain. In the present study, Fischer 344 rats were compared to the commonly used outbred Sprague-Dawley strain on several behavioral and physiological parameters in order to ascertain whether the lack of play may be related to compromised activity of brain dopamine (DA) systems. As expected, Fischer 344 rats were far less playful than Sprague-Dawley rats, with Fischer 344 rats less likely to initiate playful contacts with a playful partner and less likely to respond playfully to these contacts. We also found that Fischer 344 rats showed less of a startle response and greater pre-pulse inhibition (PPI), especially at higher prepulse intensities. The increase in PPI seen in the Fischer 344 rat could be due to reduced DA modulation of sensorimotor gating and neurochemical measures were consistent with Fischer 344 rats releasing less DA than Sprague-Dawley rats. Fast scan cyclic voltammetry (FSCV) revealed Fischer 344 rats had less evoked DA release in dorsal and ventral striatal brain slices and high-performance liquid chromatography revealed Fischer 344 rats to have less DA turnover in the striatum and prefrontal cortex. We also found DA-dependent forms of cortical plasticity were deficient in the striatum and prefrontal cortex of the Fischer 344 rat. Taken together, these data indicate that deficits in play and enhanced PPI of Fischer 344 rats may be due to reduced DA modulation of corticostriatal and mesolimbic/mesocortical circuits critical to the execution of these behaviors

Superconducting properties of Nb thin films deposited on porous silicon templates

Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering on the porous Si substrates, inherited their structure made of holes of 5 or 10 nm diameter and of 10 to 40 nm spacing, which provide an artificial pinning structure. The superconducting properties were investigated by transport measurements performed in the presence of magnetic field for different film thickness and substrates with different interpore spacing. Perpendicular upper critical fields measurements present peculiar features such as a change in the H_c2(T) curvature and oscillations in the field dependence of the superconducting resistive transition width at H=1 Tesla. This field value is much higher than typical matching fields in perforated superconductors, as a consequence of the small interpore distance.Comment: accepted for publication on Journal of Applied Physic

You and the Time

A medic reflects on how things have changed in his life over time. Articles, stories, and other compositions in this archive were written by participants in the Mighty Pen Project. The program, developed by author David L. Robbins, and in partnership with Virginia Commonwealth University and the Virginia War Memorial in Richmond, Virginia, offers veterans and their family members a customized twelve-week writing class, free of charge. The program encourages, supports, and assists participants in sharing their stories and experiences of military experience so both writer and audience may benefit

Autoactivación de cemento de escorias con polvo de vidrio de descarte

The aim of this study is to evaluate the behavior of glass powder waste as alkaline activator of slag when both are used in blended cement. The slag blended cement was prepared with 70% slag, and then the slag was replaced with 10-20% glass powder by mass. The self-activation concept is here introduced. Ground glass releases alkalis through dissolution in a slow and sustained way over time. This would activate slag. Ground glass improves fluidity of mortars and the compressive strength overcomes dilution and increases with age due to the combined pozzolanic action of slag and glass. The proposed blended cement has better mechanical properties than slag-cement. The proposed blended cement has better mechanical properties than slag-cement and due to less use of slag, it becomes more sustainable and it contributes to waste management.El objetivo del presente trabajo es evaluar el comportamiento de un residuo molido de vidrio como activador interno de la escoria cuando ambos son usados en un cemento mezcla. El cemento de escoria fue preparado con un 70% de escoria y luego la escoria se reemplazó en un 10 y 20% en masa por vidrio molido. Este trabajo introduce el concepto de auto-activación. El vidrio molido libera álcalis por disolución, en forma lenta y sostenida en el tiempo que activarían la escoria. La presencia de vidrio molido mejora la fluidez de los morteros y la resistencia a compresión supera la dilución y crece con la edad por la acción puzolánica combinada de la escoria y el vidrio. El cemento mezcla propuesto tiene mejores propiedades mecánicas que el cemento de escorias pero con menor contenido de escoria por lo que es más sustentable y contribuye al manejo de residuos

Spectroscopic behaviour of some superconducting materials containing tetraoxoanions

A number of materials of composition YSr₂Cu₂.(XO₄)₀.₂Oy(X = S, P, V) and others in which Y (III) was partially replaced by Sr(II) and/or Ca(II) were prepared by solid state reactions. Their unit cell parameters were determined and refined from X-ray powder data. The infrared spectra of the different tetraoxoanions incorporated in these materials were analyzed and discussed in detail. The vibrational modes of the other structural units present in these lattices were also approximately assigned in comparison with known spectral data of related materials.Centro de Química Inorgánic

Unsupervised Learning in Precision Medicine: Unlocking Personalized Healthcare through AI

Integrating Artificial Intelligence (AI) into Precision Medicine (PM) is redefining healthcare, enabling personalized treatments tailored to individual patients based on their genetic code, environment, and lifestyle. AI’s ability to analyze vast and complex datasets, including genomics and medical records, facilitates the identification of hidden patterns and correlations, which are critical for developing personalized treatment plans. Unsupervised Learning (UL) is particularly valuable in PM as it can analyze unstructured and unlabeled data to uncover novel disease subtypes, biomarkers, and patient stratifications. By revealing patterns that are not explicitly labeled, unsupervised algorithms enable the discovery of new insights into disease mechanisms and patient variability, advancing our understanding of individual responses to treatment. However, the integration of AI into PM presents some challenges, including concerns about data privacy and the rigorous validation of AI models in clinical practice. Despite these challenges, AI holds immense potential to revolutionize PM, offering a more personalized, efficient, and effective approach to healthcare. Collaboration among AI developers and clinicians is essential to fully realize this potential and ensure ethical and reliable implementation in medical practice. This review will explore the latest emerging UL technologies in the biomedical field with a particular focus on PM applications and their impact on human health and well-being

Dopaminergic modulation of affective and social deficits induced by prenatal glucocorticoid exposure

Prenatal stress or exposure to elevated levels of glucocorticoids (GCs) can impair specific neurobehavioral circuits leading to alterations in emotional processes later in life. In turn, emotional deficits may interfere with the quality and degree of social interaction. Here, by using a comprehensive behavioral approach in combination with the measurement of ultrasonic vocalizations, we show that in utero GC (iuGC)-exposed animals present increased immobility in the forced swimming test, pronounced anhedonic behavior (both anticipatory and consummatory), and an impairment in social interaction at different life stages. Importantly, we also found that social behavioral expression is highly dependent on the affective status of the partner. A profound reduction in mesolimbic dopaminergic transmission was found in iuGC animals, suggesting a key role for dopamine (DA) in the etiology of the observed behavioral deficits. Confirming this idea, we present evidence that a simple pharmacological approach—acute L-3,4-dihydroxyphenylacetic acid (L-DOPA) oral administration, is able to normalize DA levels in iuGC animals, with a concomitant amelioration of several dimensions of the emotional and social behaviors. Interestingly, L-DOPA effects in control individuals were not so straightforward; suggesting that both hypo- and hyperdopaminergia are detrimental in the context of such complex behaviors.This work was supported by a grant of Institute for the Study of Affective Neuroscience (ISAN) and Janssen Neurosciences Prize. SB and AJR have Fundacao para a Ciencia e Tecnologia (FCT) fellowships (SFRH/BD/89936/2012; SFRH/BPD/33611/2009)

Effects of scleroderma antibodies and pooled human immunoglobulin on anal sphincter and colonic smooth muscle function.

BACKGROUND & AIMS: Patients with systemic sclerosis (SSc) have impairments in gastrointestinal smooth muscle function. The disorder has been associated with circulating antibodies to cholinergic muscarinic the type-3 receptor (M(3)-R). We investigated whether it is possible to neutralize these antibodies with pooled human IgGs (pooledhIgG). METHODS: We studied the effects of IgGs purified from patients with SSc (SScIgGs) on cholinergic nerve stimulation in rat colon tissues. We also examined the effects of SScIgGs on M(3)-R activation by bethanechol (BeCh), M(3)-R occupancy, and receptor binding using immunofluorescence, immunoblot, and enzyme-linked immunosorbent analyses of human internal anal sphincter (IAS) smooth muscle cells, before and after administration of pooledhIgG. Functional displacement of M(3)-R occupancy by the SScIgGs was compared with that of other IgGs during the sustained phase of BeCh-induced contraction of intact smooth muscles from rats. RESULTS: SScIgG significantly attenuated neurally mediated contraction and acetylcholine release in rat colon as well as BeCh-induced sustained contraction of the IAS smooth muscle. In immunofluorescence analysis, SScIgG co-localized with M(3)-R. In immunoblot and enzyme-linked immunosorbent analyses, M(3)-R loop-2 peptide and human IAS SMC membrane lysates bound significant amounts of SScIgG, compared with IgGs from healthy individuals and pooledhIgG. Binding was attenuated significantly by application of pooledhIgG, which by itself had no significant effect. Incubation of samples with pooledhIgG, or mixing pooledhIgG with SScIgG before administration to tissues, significantly reduced binding of SScIgG, indicating that pooledhIgG prevents SScIgG blockade of M(3)-R. CONCLUSIONS: In studies of rat and human tissues, pooled human IgG prevent and reverses the cholinergic dysfunction associated with the progressive gastrointestinal manifestations of SSc by neutralizing functional M(3)-R antibodies present in the circulation of patients with SSc

Growth of dark matter perturbations during kination

If the Universe's energy density was dominated by a fast-rolling scalar field while the radiation bath was hot enough to thermally produce dark matter, then dark matter with larger-than-canonical annihilation cross sections can generate the observed dark matter relic abundance. To further constrain these scenarios, we investigate the evolution of small-scale density perturbations during such a period of kination. We determine that once a perturbation mode enters the horizon during kination, the gravitational potential drops sharply and begins to oscillate and decay. Nevertheless, dark matter density perturbations that enter the horizon during an era of kination grow linearly with the scale factor prior to the onset of radiation domination. Consequently, kination leaves a distinctive imprint on the matter power spectrum: scales that enter the horizon during kination have enhanced inhomogeneity. We also consider how matter density perturbations evolve when the dominant component of the Universe has a generic equation-of-state parameter w. We find that matter density perturbations do not grow if they enter the horizon when 01/3, their growth is faster than the logarithmic growth experienced during radiation domination. The resulting boost to the small-scale matter power spectrum leads to the formation of enhanced substructure, which effectively increases the dark matter annihilation rate and could make thermal dark matter production during an era of kination incompatible with observations