Bonding of gold clusters, , 16, and 20, on MgO(100) and on thin MgO films supported on Mo(100) is investigated using first-principles density-functional theory. Enhanced adhesive bonding is found for ...clusters deposited on metal-supported MgO films of thickness up to about 1 nm, or 4 to 5 MgO layers, originating from electrostatic interaction between the underlying metal and metal-induced excess electronic charge accumulated at the cluster interface with the oxide film. The increased wetting propensity is accompanied by a dimensionality crossover from three-dimensional optimal cluster geometries on MgO(100) to energetically favored two-dimensional structures on the metal-supported films.
Interest in right minithoracotomy mitral valve surgery (MVS) is rapidly growing and, to date, different perfusion strategies and aortic clamping techniques are available. However each approach ...carries specific advantages and drawbacks. This retrospective study analyses our experience in right minithoracotomy MVS with different arterial perfusion and aortic clamping strategies, highlighting the results of a patient tailored approach.
Between March 2009 and March 2014, 460 patients with a full preoperative work-up that included also aortoiliac-femoral axis' screening underwent right minithoracotomy MVS. One hundred and eight were redo cases (23.5%), 63 had aortoiliac atheromatous disease or significant tortuosity (13.7%), and 38 had chronic obstructive pulmonary disease (8.3%). Based on anatomy and comorbidities, each patient was allocated to the most appropriate of 3 approaches: femoral arterial cannulation with endoaortic balloon (P+EB) (247, 53.7%) or with transthoracic clamp (P+XC) (150, 32.6%), and direct aortic cannulation with endoaortic balloon occlusion (C+EB) (63, 13.7%).
No cases of aortic dissection were reported. Early outcome were similar between the 3 groups; no differences were reported in terms of stroke rate (1.7% in the P+EB, 2% in the P+XC, and no cases in the C+EB group; p = NS) and 30-day mortality (2.1% in the P+EB, 2.7% in the P+XC, and 1.6% in the C+EB group; p = NS). Logistic regression showed no influences of arterial perfusion and aortic clamping techniques on 30-day mortality and stroke.
Right minithoracotomy MVS can routinely be performed with favorable outcomes in all comers when perfusion strategies and clamping techniques are carefully selected after proper evaluation of the patient's preoperative characteristics.
Conductive tattoo nanosheets are fabricated on top of decal transfer paper and transferred on target surfaces as temporary transfer tattoos. Circuits are patterned with ink-jet printing. Tattoo ...nanosheets are envisioned as unperceivable human-device interfaces because of conformal adhesion to complex surfaces including skin. They are tested as dry electrodes for surface electromyography (sEMG), which permits the control of a robotic hand.
Abstract
During primate arboreal locomotion, substrate orientation modifies body axis orientation and biomechanical contribution of fore- and hindlimbs. To characterize the role of cortical ...oscillations in integrating these locomotor demands, we recorded electrocorticographic activity from left dorsal premotor, primary motor, and supplementary motor cortices of three common marmosets moving across a branch-like small-diameter pole, fixed horizontally or vertically. Animals displayed behavioral adjustments to the task, namely, the horizontal condition mainly induced quadrupedal walk with pronated/neutral forelimb postures, whereas the vertical condition induced walk and bound gaits with supinated/neutral postures. Examination of cortical activity suggests that β (16–35 Hz) and γ (75–100 Hz) oscillations could reflect different processes in locomotor adjustments. During task, modulation of γ ERS by substrate orientation (horizontal/vertical) and epoch (preparation/execution) suggests close tuning to movement dynamics and biomechanical demands. β ERD was essentially modulated by gait (walk/bound), which could illustrate contribution to movement sequence and coordination. At rest, modulation of β power by substrate orientation underlines its role in sensorimotor processes for postural maintenance.
Electrocorticography (ECoG) is becoming a common tool for clinical applications, such as preparing patients for epilepsy surgery or localizing tumor boundaries, as it successfully balances ...invasiveness and information quality. Clinical ECoG arrays use millimeter-scale electrodes and centimeter-scale pitch and cannot precisely map neural activity. Higher-resolution electrodes are of interest for both current clinical applications, providing access to more precise neural activity localization and novel applications, such as neural prosthetics, where current information density and spatial resolution is insufficient to suitably decode signals for a chronic brain-machine interface. Developing such electrodes is not trivial because their small contact area increases the electrode impedance, which seriously affects the signal-to-noise ratio, and adhering such an electrode to the brain surface becomes critical. The most straightforward approach requires increasing the array conformability with flexible substrates while improving the electrode performance using materials with superior electrochemical properties. In this paper, we propose an ultra-flexible and conformable polyimide-based micro-ECoG array of submillimeter recording sites electrochemically coated with high surface area conductive polymer-carbon nanotube composites to improve their brain-electrical coupling capabilities. We characterized our devices both electrochemically and by recording from rat somatosensory cortex in vivo. The performance of the coated and uncoated electrodes was directly compared by simultaneously recording the same neuronal activity during multiwhisker deflection stimulation. Finally, we assessed the effect of electrode size on the extraction of somatosensory evoked potentials and found that in contrast to the normal high-impedance microelectrodes, the recording capabilities of our low-impedance microelectrodes improved upon reducing their size from 0.2 to 0.1 mm.
Key points
The cortical mechanisms of grasping have been extensively studied in macaques and humans; here, we investigated whether common marmosets could rely on similar mechanisms despite strong ...differences in hand morphology and grip diversity.
We recorded electrocorticographic activity over the sensorimotor cortex of two common marmosets during the execution of different grip types, which allowed us to study cortical activity (power spectrum) and physiologically inferred connectivity (phase‐slope index).
Analyses were performed in beta (16–35 Hz) and gamma (75–100 Hz) frequency bands and our results showed that beta power varied depending on grip type, whereas gamma power displayed clear epoch‐related modulation.
Strength and direction of inter‐area connectivity varied depending on grip type and epoch.
These findings suggest that fundamental control mechanisms are conserved across primates and, in future research, marmosets could represent an adequate model to investigate primate brain mechanisms.
The cortical mechanisms of grasping have been extensively studied in macaques and humans. Here, we investigated whether common marmosets could rely on similar mechanisms despite striking differences in manual dexterity. Two common marmosets were trained to grasp‐and‐pull three objects eliciting different hand configurations: whole‐hand, finger and scissor grips. The animals were then chronically implanted with 64‐channel electrocorticogram arrays positioned over the left premotor, primary motor and somatosensory cortex. Power spectra, reflecting predominantly cortical activity, and phase‐slope index, reflecting the direction of information flux, were studied in beta (16–35 Hz) and gamma (75–100 Hz) bands. Differences related to grip type, epoch (reach, grasp) and cortical area were statistically assessed. Results showed that whole‐hand and scissor grips triggered stronger beta desynchronization than finger grip. Task epochs clearly modulated gamma power, especially for finger and scissor grips. Considering effective connectivity, finger and scissor grips evoked stronger outflow from primary motor to premotor cortex, whereas whole‐hand grip displayed the opposite pattern. These findings suggest that fundamental control mechanisms, relying on adjustments of cortical activity and connectivity, are conserved across primates. Consistently, marmosets could represent a good model to investigate primate brain mechanisms.
Key points
The cortical mechanisms of grasping have been extensively studied in macaques and humans; here, we investigated whether common marmosets could rely on similar mechanisms despite strong differences in hand morphology and grip diversity.
We recorded electrocorticographic activity over the sensorimotor cortex of two common marmosets during the execution of different grip types, which allowed us to study cortical activity (power spectrum) and physiologically inferred connectivity (phase‐slope index).
Analyses were performed in beta (16–35 Hz) and gamma (75–100 Hz) frequency bands and our results showed that beta power varied depending on grip type, whereas gamma power displayed clear epoch‐related modulation.
Strength and direction of inter‐area connectivity varied depending on grip type and epoch.
These findings suggest that fundamental control mechanisms are conserved across primates and, in future research, marmosets could represent an adequate model to investigate primate brain mechanisms.
Nonsense mutations cause several genetic diseases such as cystic fibrosis, Duchenne muscular dystrophy, β-thalassemia, and Shwachman–Diamond syndrome. These mutations induce the formation of a ...premature termination codon (PTC) inside the mRNA sequence, resulting in the synthesis of truncated polypeptides. Nonsense suppression therapy mediated by translational readthrough-inducing drugs (TRIDs) is a promising approach to correct these genetic defects. TRIDs generate a ribosome miscoding of the PTC named “translational readthrough” and restore the synthesis of full-length and potentially functional proteins. The new oxadiazole-core TRIDs NV848, NV914, and NV930 (NV) showed translational readthrough activity in nonsense-related in vitro systems. In this work, the possible off-target effect of NV molecules on natural termination codons (NTCs) was investigated. Two different in vitro approaches were used to assess if the NV molecule treatment induces NTC readthrough: (1) a study of the translational-induced p53 molecular weight and functionality; (2) the evaluation of two housekeeping proteins’ (Cys-C and β2M) molecular weights. Our results showed that the treatment with NV848, NV914, or NV930 did not induce any translation alterations in both experimental systems. The data suggested that NV molecules have a specific action for the PTCs and an undetectable effect on the NTCs.
In this paper, we present an ultraflexible tactile sensor, in a piezo-eletricoxide-semiconductor FET configuration, composed by a polyvinylidenefluoride-co-trifluoroethylene capacitor with an ...embedded readout circuitry, based on nMOS polysilicon electronics, integrated directly on polyimide. The ultraflexible device is designed according to an extended gate configuration. The sensor exhibits enhanced piezoelectric properties, thanks to the optimization of the poling procedure (with electric field up to 3 MV/cm), reaching a final piezoelectric coefficient d 33 of 47 pC/N. The device has been electromechanically tested by applying perpendicular forces with a minishaker. The tactile sensor, biased in a common-source arrangement, shows a linear response to increasing sinusoidal stimuli (up to 2 N) and increasing operating frequencies (up to 1200 Hz), obtaining a response up to 430 mV/N at 200 Hz for the sensor with the highest value of d 33 . The sensor performances were also tested after several cycles of controlled bending in different amount of humidity with the intent to investigate the device behavior in real conditions.
Stem-cell-based therapies require a high number (10⁶-10⁸) of cells, therefore in vitro expansion is needed because of the initially low amount of stem cells obtainable from human tissues. Standard ...protocols for stem cell expansion are currently based on chemically-defined culture media and animal-derived feeder-cell layers, which expose cells to additives and to xenogeneic compounds, resulting in potential issues when used in clinics. The two-photon laser polymerization technique enables three-dimensional micro-structures to be fabricated, which we named synthetic nichoids. Here we review our activity on the technological improvements in manufacturing biomimetic synthetic nichoids and, in particular on the optimization of the laser-material interaction to increase the patterned area and the percentage of cell culture surface covered by such synthetic nichoids, from a low initial value of 10% up to 88% with an optimized micromachining time. These results establish two-photon laser polymerization as a promising tool to fabricate substrates for stem cell expansion, without any chemical supplement and in feeder-free conditions for potential therapeutic uses.
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