A Unified Multimodal Interface for the RELAX High-Payload Collaborative Robot

This manuscript introduces a mobile cobot equipped with a custom-designed high payload arm called RELAX combined with a novel unified multimodal interface that facilitates Human-Robot Collaboration (HRC) tasks requiring high-level interaction forces on a real-world scale. The proposed multimodal framework is capable of combining physical interaction, Ultra Wide-Band (UWB) radio sensing, a Graphical User Interface (GUI), verbal control, and gesture interfaces, combining the benefits of all these different modalities and allowing humans to accurately and efficiently command the RELAX mobile cobot and collaborate with it. The effectiveness of the multimodal interface is evaluated in scenarios where the operator guides RELAX to reach designated locations in the environment while avoiding obstacles and performing high-payload transportation tasks, again in a collaborative fashion. The results demonstrate that a human co-worker can productively complete complex missions and command the RELAX mobile cobot using the proposed multimodal interaction framework.

Heterogeneity of management practices surrounding operable gallbladder cancer - results of the OMEGA-S international HPB surgical survey

BACKGROUND

Gallbladder cancer (GBC) is an aggressive, uncommon malignancy, with variation in operative approaches adopted across centres and few large-scale studies to guide practice. We aimed to identify the extent of heterogeneity in GBC internationally to better inform the need for future multicentre studies.

METHODS

A 34-question online survey was disseminated to members of the European-African Hepatopancreatobiliary Association (EAHPBA), American Hepatopancreatobiliary Association (AHPBA) and Asia-Pacific Hepatopancreatobiliary Association (A-PHPBA) regarding practices around diagnostic workup, operative approach, utilization of neoadjuvant and adjuvant therapies and surveillance strategies.

RESULTS

Two hundred and three surgeons responded from 51 countries. High liver resection volume units (>50 resections/year) organised HPB multidisciplinary team discussion of GBCs more commonly than those with low volumes (p < 0.0001). Management practices exhibited areas of heterogeneity, particularly around operative extent. Contrary to consensus guidelines, anatomical liver resections were favoured over non-anatomical resections for T3 tumours and above, lymphadenectomy extent was lower than recommended, and a minority of respondents still routinely excised the common bile duct or port sites.

CONCLUSION

Our findings suggest some similarities in the management of GBC internationally, but also specific areas of practice which differed from published guidelines. Transcontinental collaborative studies on GBC are necessary to establish evidence-based practice to minimise variation and optimise outcomes.

Variable stiffness locomotion with guaranteed stability for quadruped robots traversing uneven terrains

Quadruped robots are widely applied in real-world environments where they have to face the challenges of walking on unknown rough terrains. This paper presents a control pipeline that generates robust and compliant legged locomotion for torque-controlled quadruped robots on uneven terrains. The Cartesian motion planner is designed to be reactive to unexpected early and late contacts using the estimated contact forces. Moreover, we present a novel scheme of optimal stiffness modulation that aims to coordinate desired compliance and tracking performance. It optimizes joint stiffness and contact forces coordinately in a quadratic programming (QP) formulation, where the constraints of non-slipping contacts and torque limits are imposed as well. In addition, the issue of stability under variable stiffness control is solved by imposing a tank-based passivity constraint explicitly. We finally validate the proposed control pipeline on our quadruped robot CENTAURO in experiments on uneven terrains and, through comparative tests, demonstrate the improvements of the variable stiffness locomotion.

Horizon: A Trajectory Optimization Framework for Robotic Systems

This paper presents Horizon, an open-source framework for trajectory optimization tailored to robotic systems that implements a set of tools to simplify the process of dynamic motion generation. Its user-friendly Python-based API allows designing the most complex robot motions using a simple and intuitive syntax. At the same time, the modular structure of Horizon allows for easy customization on many levels, providing several recipes to handle fixed and floating-base systems, contact switching, variable time nodes, multiple transcriptions, integrators and solvers to guarantee flexibility towards diverse tasks. The proposed framework relies on direct simultaneous methods to transcribe the optimal problem into a nonlinear programming problem that can be solved by state-of-the-art solvers. In particular, it provides several off-the-shelf solvers, as well as two custom-implemented solvers, i.e. GN-SQP and Iterative Linear-Quadratic Regulator. Solutions of optimized problems can be stored for warm-starting, and re-sampled at a different frequency while enforcing dynamic feasibility. The proposed framework is validated through a number of use-case scenarios involving several robotic platforms. Finally, an in-depth analysis of a specific case study is carried out, where a highly dynamic motion (i.e., a twisting jump using the quadruped robot Spot^® from BostonDynamics¹) is generated, in order to highlight the main features of the framework and demonstrate its capabilities.

NSPG: An Efficient Posture Generator Based on Null-Space Alteration and Kinetostatics Constraints

Most of the locomotion and contact planners for multi-limbed robots rely on a reduction of the search space to improve the performance of their algorithm. Posture generation plays a fundamental role in these types of planners providing a collision-free, statically stable whole-body posture, projected onto the planned contacts. However, posture generation becomes particularly tedious for complex robots moving in cluttered environments, in which feasibility can be hard to accomplish. In this work, we take advantage of the kinematic structure of a multi-limbed robot to present a posture generator based on hierarchical inverse kinematics and contact force optimization, called the null-space posture generator (NSPG), able to efficiently satisfy the aforementioned requisites in short times. A new configuration of the robot is produced through conservatively altering a given nominal posture exploiting the null-space of the contact manifold, satisfying geometrical and kinetostatics constraints. This is achieved through an adaptive random velocity vector generator that lets the robot explore its workspace. To prove the validity and generality of the proposed method, simulations in multiple scenarios are reported employing different robots: a wheeled-legged quadruped and a biped. Specifically, it is shown that the NSPG is particularly suited in complex cluttered scenarios, in which linear collision avoidance and stability constraints may be inefficient due to the high computational cost. In particular, we show an improvement of performances being our method able to generate twice feasible configurations in the same period. A comparison with previous methods has been carried out collecting the obtained results which highlight the benefits of the NSPG. Finally, experiments with the CENTAURO platform, developed at Istituto Italiano di Tecnologia, are carried out showing the applicability of the proposed method to a real corridor scenario.

Omnidirectional Walking Pattern Generator Combining Virtual Constraints and Preview Control for Humanoid Robots

This paper presents a novel omnidirectional walking pattern generator for bipedal locomotion combining two structurally different approaches based on the virtual constraints and the preview control theories to generate a flexible gait that can be modified on-line. The proposed strategy synchronizes the displacement of the robot along the two planes of walking: the zero moment point based preview control is responsible for the lateral component of the gait, while the sagittal motion is generated by a more dynamical approach based on virtual constraints. The resulting algorithm is characterized by a low computational complexity and high flexibility, requisite for a successful deployment to humanoid robots operating in real world scenarios. This solution is motivated by observations in biomechanics showing how during a nominal gait the dynamic motion of the human walk is mainly generated along the sagittal plane. We describe the implementation of the algorithm and we detail the strategy chosen to enable omnidirectionality and on-line gait tuning. Finally, we validate our strategy through simulation experiments using the COMAN + platform, an adult size humanoid robot developed at Istituto Italiano di Tecnologia. Finally, the hybrid walking pattern generator is implemented on real hardware, demonstrating promising results: the WPG trajectories results in open-loop stable walking in the absence of external disturbances.

Metabolic control and complications in Italian people with diabetes treated with continuous subcutaneous insulin infusion

BACKGROUND AND AIM

The objective of this cross-sectional study was to evaluate the degree of glycaemic control and the frequency of diabetic complications in Italian people with diabetes who were treated with continuous subcutaneous insulin infusion (CSII).

METHODS AND RESULTS

Questionnaires investigating the organisation of diabetes care centres, individuals' clinical and metabolic features and pump technology and its management were sent to adult and paediatric diabetes centres that use CSII for treatment in Italy. Information on standard clinical variables, demographic data and acute and chronic diabetic complications was derived from local clinical management systems. The sample consisted of 6623 people with diabetes, which was obtained from 93 centres. Of them, 98.8% had type 1 diabetes mellitus, 57.2% were female, 64% used a conventional insulin pump and 36% used a sensor-augmented insulin pump. The median glycated haemoglobin (HbA_1c) level was 60 mmol/mol (7.6%). The HbA_1c target (i.e. <58 mmol/mol for age <18 years and <53 mmol/mol for age >18 years) was achieved in 43.4% of paediatric and 23% of adult participants. Factors such as advanced pump functions, higher rate of sensor use, pregnancy in the year before the study and longer duration of diabetes were associated with lower HbA_1c levels. The most common chronic complications occurring in diabetes were retinopathy, microalbuminuria and hypertension. In the year before the study, 5% of participants reported ≥1 episode of severe hypoglycaemic (SH) episodes (SH) and 2.6% reported ≥1 episode of ketoacidosis.

CONCLUSIONS

Advanced personal skills and use of sensor-based pump are associated with better metabolic control outcomes in Italian people with diabetes who were treated with CSII. The reduction in SH episodes confirms the positive effect of CSII on hypoglycaemia.

CLINICAL TRIAL REGISTRATION NUMBER

NCT 02620917 (ClinicalTrials.gov).

The protein tyrosine phosphatase PTPN22 controls forkhead box protein 3 T regulatory cell induction but is dispensable for T helper type 1 cell polarization

Protein tyrosine phosphatases (PTPs) regulate T cell receptor (TCR) signalling and thus have a role in T cell differentiation. Here we tested whether the autoimmune predisposing gene PTPN22 encoding for a PTP that inhibits TCR signalling affects the generation of forkhead box protein 3 (FoxP3)(+) T regulatory (Treg ) cells and T helper type 1 (Th1) cells. Murine CD4(+) T cells isolated from Ptpn22 knock-out (Ptpn22(KO) ) mice cultured in Treg cell polarizing conditions showed increased sensitivity to TCR activation compared to wild-type (WT) cells, and subsequently reduced FoxP3 expression at optimal-to-high levels of activation. However, at lower levels of TCR activation, Ptpn22(KO) CD4(+) T cells showed enhanced expression of FoxP3. Similar experiments in humans revealed that at optimal levels of TCR activation PTPN22 knock-down by specific oligonucleotides compromises the differentiation of naive CD4(+) T cells into Treg cells. Notably, in vivo Treg cell conversion experiments in mice showed delayed kinetic but overall increased frequency and number of Treg cells in the absence of Ptpn22. In contrast, the in vitro and in vivo generation of Th1 cells was comparable between WT and Ptpn22(KO) mice, thus suggesting PTPN22 as a FoxP3-specific regulating factor. Together, these results propose PTPN22 as a key factor in setting the proper threshold for FoxP3(+) Treg cell differentiation.

The ALPPS procedure for hepatocellular carcinoma

BACKGROUND

The main limiting factor to major hepatic resections is the amount of the future liver remnant (FLR). Associating Liver Partition with Portal Vein Ligation for Staged Hepatectomy (ALPPS) is a procedure which induces a rapid hypertrophy of the FLR in patients with non-resectable liver tumours.

METHODS

ALPPS is a surgical technique of in-situ splitting of the liver along the main portal scissura or the right side of the falciform ligament, in association with portal vein ligation in order to induce a rapid hypertrophy of the left FLR.

RESULTS

The median FLR volume increase was 18.7% within one week after the first step and 38.6% after the second step. At the first step the median operating time was 300 min, blood transfusions were not required in any case, median blood loss was 150 cc. At the second step median operating time was 180 min, median blood loss was 50 cc, none of the patients required intra-operative blood. All patients are alive at a median follow up of 9 months.

CONCLUSIONS

This novel strategy seems to be feasible even in the context of a cirrhotic liver, and demonstrates the capacity to reach a sufficient FLR within a shorter interval of time.

The ALPPS procedure for hepatocellular carcinoma

BACKGROUND

The main limiting factor to major hepatic resections is the amount of the future liver remnant (FLR). Associating Liver Partition with Portal Vein Ligation for Staged Hepatectomy (ALPPS) is a procedure which induces a rapid hypertrophy of the FLR in patients with non-resectable liver tumours.

METHODS

ALPPS is a surgical technique of in-situ splitting of the liver along the main portal scissura or the right side of the falciform ligament, in association with portal vein ligation in order to induce a rapid hypertrophy of the left FLR.

RESULTS

The median FLR volume increase was 18.7% within one week after the first step and 38.6% after the second step. At the first step the median operating time was 300 min, blood transfusions were not required in any case, median blood loss was 150 cc. At the second step median operating time was 180 min, median blood loss was 50 cc, none of the patients required intra-operative blood. All patients are alive at a median follow up of 9 months.

CONCLUSIONS

This novel strategy seems to be feasible even in the context of a cirrhotic liver, and demonstrates the capacity to reach a sufficient FLR within a shorter interval of time.

Hanging of the hepatic veins septa: a safe control prior and during outflow anastomosis in liver transplantation

Inferior vena cava (IVC) preservation during orthotopic liver transplantation (OLT) is known as the "piggyback" technique. The end-to-side anastomosis is constructed between the graft's IVC and recipient's hepatic veins using a Satinsky side clamp applied in a transverse position. To stabilize the large Satinsky clamp and preserve a sufficient vascular stump after hepatectomy and before graft implantation, we propose a technical innovation consisting of hanging the septa between the left and middle hepatic vein and between the middle and right hepatic vein using 2 tapes. This technique showed some advantages when performing the caval outflow anastomosis, representing a further technical refinement of the piggyback end-to-side technique for the implantation on the 3 hepatic veins. From November 2001 to September 2012, we performed 272 consecutive OLT at our institution with the piggyback technique using the hanging of the hepatic veins septa in all cases. In conclusion, the hanging of the 3 hepatic veins septa presented in this study represents a simple, safe and reproducible technique for the outflow anastomosis using the piggyback technique.

Constitutive expression of beta-N-acetylhexosaminidase in a microglial cell line: transcriptional modulation by lipopolysaccharide and serum factors

We investigated the expression of the alpha- and beta-subunits of the lysosomal enzyme beta-N-acetylhexosaminidase in the BV-2 microglial cell line under different culture conditions. Beta-N-acetylhexosaminidase from BV-2 microglia cells was separated into its constituent isoenzymes on diethylaminoethyl (DEAE) cellulose, and its activity was monitored with 4-methylumbelliferyl-beta-N-acetylglucosamine and 4-methylumbelliferyl-beta-N-acetylglucosamine-6-sulphate substrates. Forms corresponding to the mouse isoenzymes A and B were present in the cells incubated in serum-supplemented medium as well as in serum-free medium. Lipopolysaccharide, a well-known activator of microglia in vitro, added to the BV-2 cells in serum-supplemented medium induced a decrease in the specific enzymatic activity determined with the 4-methylumbelliferyl-beta-N-acetylglucosamine substrate. Lipopolysaccharide had no effect on hexosaminidase isoenzyme pattern of BV-2 cells in serum-supplemented medium. The level of alpha-subunit mRNA was increased and the level of beta-subunit mRNA was decreased in BV-2 cells incubated in serum-supplemented medium plus lipopolysaccharide. In the cells incubated in a serum-free medium no significant changes in the hexosaminidase-specific activities towards the above substrates were observed. Interestingly, increased expression of alpha- and beta-subunit mRNA was evident in comparison with cultures in serum-supplemented medium. The present results suggest that the BV-2 cell line may be a useful tool to study the possible role of microglia in the metabolism of brain glycolipids.