Hybrid parameter identification of a multi-modal underwater soft robot.

We introduce an octopus-inspired, underwater, soft-bodied robot capable of performing waterborne pulsed-jet propulsion and benthic legged-locomotion. This vehicle consists for as much as 80% of its volume of rubber-like materials so that structural flexibility is exploited as a key element during both modes of locomotion. The high bodily softness, the unconventional morphology and the non-stationary nature of its propulsion mechanisms require dynamic characterization of this robot to be dealt with by ad hoc techniques. We perform parameter identification by resorting to a hybrid optimization approach where the characterization of the dual ambulatory strategies of the robot is performed in a segregated fashion. A least squares-based method coupled with a genetic algorithm-based method is employed for the swimming and the crawling phases, respectively. The outcomes bring evidence that compartmentalized parameter identification represents a viable protocol for multi-modal vehicles characterization. However, the use of static thrust recordings as the input signal in the dynamic determination of shape-changing self-propelled vehicles is responsible for the critical underestimation of the quadratic drag coefficient.

Learning the inverse kinetics of an octopus-like manipulator in three-dimensional space.

This work addresses the inverse kinematics problem of a bioinspired octopus-like manipulator moving in three-dimensional space. The bioinspired manipulator has a conical soft structure that confers the ability of twirling around objects as a real octopus arm does. Despite the simple design, the soft conical shape manipulator driven by cables is described by nonlinear differential equations, which are difficult to solve analytically. Since exact solutions of the equations are not available, the Jacobian matrix cannot be calculated analytically and the classical iterative methods cannot be used. To overcome the intrinsic problems of methods based on the Jacobian matrix, this paper proposes a neural network learning the inverse kinematics of a soft octopus-like manipulator driven by cables. After the learning phase, a feed-forward neural network is able to represent the relation between manipulator tip positions and forces applied to the cables. Experimental results show that a desired tip position can be achieved in a short time, since heavy computations are avoided, with a degree of accuracy of 8% relative average error with respect to the total arm length.

A 3D steady-state model of a tendon-driven continuum soft manipulator inspired by the octopus arm.

Control and modelling of continuum robots are challenging tasks for robotic researchers. Most works on modelling are limited to piecewise constant curvature. In many cases they neglect to model the actuators or avoid a continuum approach. In particular, in the latter case this leads to a complex model hardly implemented. In this work, a geometrically exact steady-state model of a tendon-driven manipulator inspired by the octopus arm is presented. It takes a continuum approach, fast enough to be implemented in the control law, and includes a model of the actuation system. The model was experimentally validated and the results are reported. In conclusion, the model presented can be used as a tool for mechanical design of continuum tendon-driven manipulators, for planning control strategies or as internal model in an embedded system.

An octopus-bioinspired solution to movement and manipulation for soft robots.

Soft robotics is a challenging and promising branch of robotics. It can drive significant improvements across various fields of traditional robotics, and contribute solutions to basic problems such as locomotion and manipulation in unstructured environments. A challenging task for soft robotics is to build and control soft robots able to exert effective forces. In recent years, biology has inspired several solutions to such complex problems. This study aims at investigating the smart solution that the Octopus vulgaris adopts to perform a crawling movement, with the same limbs used for grasping and manipulation. An ad hoc robot was designed and built taking as a reference a biological hypothesis on crawling. A silicone arm with cables embedded to replicate the functionality of the arm muscles of the octopus was built. This novel arm is capable of pushing-based locomotion and object grasping, mimicking the movements that octopuses adopt when crawling. The results support the biological observations and clearly show a suitable way to build a more complex soft robot that, with minimum control, can perform diverse tasks.

IFN-beta1a modulates the expression of CTLA-4 and CD28 splice variants in human mononuclear cells: induction of soluble isoforms.

Recently, mRNA encoding soluble isoforms of CD28 and CTLA-4 have been described in human lymphocytes. We demonstrate that interferon-beta1a (IFN-beta1a) can enhance the expression of these transcripts in human mononuclear cells. Because soluble CD28 and CTLA-4 molecules might affect T cell activation, our findings suggest an additional means whereby IFN-beta therapy might exert its immunomodulatory effects in multiple sclerosis (MS).

Interferon beta-1a downregulates TNFalpha-induced intercellular adhesion molecule 1 expression on brain microvascular endothelial cells through a tyrosine kinase-dependent pathway.

TNFalpha (100 U/ml, 24 h) upregulated intercellular adhesion molecule 1 (ICAM1) expression on brain microvascular endothelial cell (BMEC) culture. The tyrosine kinase (TK) inhibitor genestein (100 microgram/ml), the protein kinase C (PKC) inhibitor staurosporin (1 nM), and interferon (IF) beta-1a (1000 U/ml) antagonized TNFalpha effect. When an ineffective dose of IFbeta-1a (100 U/ml) was challenged with ineffective doses of either genestein (10 microgram/ml) or staurosporin (0.1 nM), the combination IFbeta-1a-genestein significantly reduced TNFalpha-induced ICAM1 expression whereas IFbeta-1a-staurosporin did not. These findings indicate that a TK- rather than a PKC-dependent mechanism is involved in the modulation of TNFalpha response by IFbeta-1a on BMECs.

Effects of rIFN-beta-1b on serum circulating ICAM-1 in relapsing remitting multiple sclerosis and on the membrane-bound ICAM-1 expression on brain microvascular endothelial cells.

rIFN-beta reduces the frequency of the gadolinium-enhancing (Gd+) magnetic resonance imaging (MRI) lesions in relapsing remitting (RR) MS. Its mechanism of action on improving the integrity of the blood-brain barrier (BBB) remains unclear. We investigated the effect of rIFN-beta-1b on the soluble intercellular adhesion molecule-1 (sICAM-1) serum levels (ELISA) in 36 RR MS patients receiving treatment with rIFN-beta for 1 year, and also the TNF-alpha - induced membrane-bound ICAM-1 (mICAM-1) expression on cultured rat brain microvascular endothelial cells (BMECs). In vivo data showed that sICAM-1 serum levels at baseline significantly increased (P<0.01) in 12 months of rIFN-beta-1b treatment. The increase paralleled a clinical and MRI improvement. In the second semester of the treatment the integrated area under the curve of Expanded Disability Status Score normalised to entry baseline (DeltaEDSS AUC) was significantly (P<0.05) smaller than in the first semester. The percentage of patients with Gd+MRI decreased significantly (P<0.05) in the first (33%) and second (29%) semesters of treatment compared to baseline (62%). In vitro experiments showed that the incubation of BMEC monolayer with 100 u/ml of TNF-alpha for 24 h significantly (P<0.05) increased mICAM-1 expression, whereas 2000 u/ml of rIFN-beta-1b for 72 h did not modify the baseline levels. The incubation of BMEC with 2000 u/ml of rIFN-beta-1b for 48 h followed by combined IFN-beta-1b and TNF-alpha for 24 h significantly (P<0.05) downregulated TNF-alpha-induced mICAM-1 expression. These results suggest that the effect of rIFN-beta-1b on the BBB may be mediated by changes in both sICAM-1 serum levels and mICAM-1 BMEC expression.

Inhibition of protein kinase C counteracts TNFalpha-induced intercellular adhesion molecule 1 expression and fluid phase endocytosis on brain microvascular endothelial cells.

TNFalpha (100 U/ml, 24 h) upregulated intercellular adhesion molecule 1 (ICAM1) expression and fluid phase endocytosis (FPE) of horseradish peroxidase on brain microvascular endothelial cell (BMEC) culture. The protein kinase C (PKC) inhibitor staurosporin (0. 5-10 nM) antagonized ICAM1 expression and FPE due to TNFalpha, whereas the protein kinase A inhibitor H89 (0.5-10 nM) did not. These findings indicate that a PKC-dependent mechanism may affect TNFalpha signalling on different barrier properties of BMECs.

Interferon beta-1a prevents the effects of lipopolysaccharide on embryonic brain microvessels.

By means of light and electron microscopy we have studied the effect of interferon beta-1a (IFNbeta-1a) in the optic tecta of 20-day-old chick embryos under normal conditions and after exposure to lipopolysaccharide (LPS) which mimics the blood-brain barrier (BBB) disruption in meningoencephalitis. Optic tecta were examined for: (i) ultrastructure by means of transmission electron microscopy; (ii) the immunohistochemical localization of HT7 antigen, a specific marker of differentiation of the brain microvessels; (iii) the brain microvessel permeability, by means of horseradish peroxidase (HRP) tracer; (iv) the expression of microvessel glycoconjugates, by means of lectin histochemistry, using Ricinus communis agglutinin-I (RCA-I), specific for beta-D-galactosyl moieties and Wheat Germ agglutinin (WGA) specific for sialyl and N-acetylglucosaminyl moieties. A morphometric evaluation of brain microvessel permeability and of glycoconjugate expression was also performed. In control- and in IFNbeta-1a-treated embryos, HRP was confined to the vessel lumina which were sealed by the interendothelial tight junctions. RCA-I binding sites were recognizable both in the basal membranes and in the tight junctions, while WGA sites were present on the luminal side of the endothelial cells. HRP was blocked in the vessels lumina by the interendothelial tight junctions. After LPS treatment, HRP showed an extravascular localization and the labeling of microvessels by anti-HT7 antibodies disappeared. RCA-I binding was only found ultrastructurally and appeared as irregularly clustered gold particles, in the cleft of damaged tight junctions, but were no longer detectable in the endothelial basement membranes. After pretreatment of LPS-treated embryos with IFNbeta-1a, the vessel permeability to HRP strongly decreased and the vessels showed the normal pattern of HT7 protein and of the RCA-I binding sites. These results indicate that the changes induced by LPS in the endothelial cells are prevented by IFNbeta-1a.

"Apraxia of eyelid opening" induced by levodopa therapy and apomorphine in atypical parkinsonism (possible progressive supranuclear palsy): a case report.

We report a female patient in whom so-called apraxia of eyelid opening (AEO) developed after the onset of possible progressive supranuclear palsy (National Institute of Neurological Disorders and Stroke criteria) and the introduction of antiparkinsonian medications including levodopa. Although parkinsonian symptoms responded poorly to levodopa, AEO worsened after increasing levodopa dosage and disappeared when levodopa was discontinued. Later, a dose of apomorphine widely accepted for acute tests had no significant effect on limb motor activity but induced AEO. Overall, these observations are grounds for thinking that AEO developing in the course of parkinsonism may be either disease- or drug-related. The possibility of manipulating dopaminergic treatment should always be considered when dealing with AEO associated with parkinsonism.

ICAM 1 expression and fluid phase endocytosis of cultured brain microvascular endothelial cells following exposure to interferon beta-1a and TNFalpha.

We have studied the effect of interferon (IF) beta-1a on the basal and TNFalpha-induced intercellular adhesion molecule 1 (ICAM 1) expression and fluid phase endocytosis (FPE) of horseradish peroxidase in cultured rat brain microvascular endothelial cells. Neither basal ICAM 1 expression nor basal FPE were significantly affected by 24-72 h exposure to 1000 U/ml IFbeta-1a. ICAM 1 induction and FPE enhancement caused by 100 U/ml TNFalpha for 24 h was not influenced by simultaneous administration of 1000 U/ml IFbeta-1a. Treatment of cultures with IFbeta-1a for 48 h followed by 24-h coincubation with TNFalpha (100 U/ml) and IFbeta-1a (1000 U/ml) resulted in significant downregulation of TNFalpha-induced ICAM 1 expression and FPE. Downregulation of TNFalpha-induced ICAM 1 expression was not observed when combined treatment with TNFalpha (100 U/ml) and IFbeta-1a (1000 U/ml) for 24 h was followed by 48 h exposure to IFbeta-1a. We concluded that the blood-brain barrier endothelium may be a target of IFbeta-1a. Further, these in vitro findings may correlate with the results of recent clinical trials indicating that chronic treatment of relapsing remitting multiple sclerosis with IFbeta-1a prevents both clinical exacerbations and the appearance on Magnetic Resonance Imaging of new lesions enhanced by gadolinium which is taken up by increased transendothelial fluid phase vesicular transport.

Isolated so-called apraxia of eyelid opening: report of 10 cases and a review of the literature.

So-called apraxia of eyelid opening (scAEO) has been described chiefly in the context of extrapyramidal disorders. We described 10 new patients with scAEO developing in the absence of any other CNS sign and reviewed the 11 cases with isolated scAEO reported in the literature. Combining our patients and those from the literature, peak age at onset was in the 6th decade and there was a female preponderance of 2:1. The characteristic inability to initiate lid elevation was frequently associated with failure to sustain lid elevation, thus suggesting that eyelid motor control may be abnormal in isolated scAEO. Antecedent events included ocular signs and symptoms consistent with diseases of eyes or face (4 cases in our series and 2 in the literature), chronic treatment with flunarizine (1 case), and family history of dystonia (1 case). Flunarizine discontinuation led to sustained remission of the eyelid disturbance. Overall, these clues suggest the involvement of the extrapyramidal system in the pathophysiology of isolated scAEO. Familial clustering of isolated scAEO in one of our patients may be in favor of a genetic contribution. In our series, botulinum toxin administration close to the pretarsal part of the orbicularis oculi muscle significantly improved scAEO in 8/10 cases, whereas orbital/preseptal injection had no effect. We conclude that the term 'apraxia' may not be the correct descriptive term even when the eyelid disturbance occurs without any other CNS disease.