3,249 research outputs found
Performance Analysis of Low-Cost Tracking System for Mobile Robots
This paper proposes a reliable and straightforward approach to mobile robots (or moving objects in general) indoor tracking, in order to perform a preliminary study on their dynamics. The main features of this approach are its minimal and low-cost setup and a user-friendly interpretation of the data generated by the ArUco library. By using a commonly available camera, such as a smartphone one or a webcam, and at least one marker for each object that has to be tracked, it is possible to estimate the pose of these markers, with respect to a reference conveniently placed in the environment, in order to produce results that are easily interpretable by a user. This paper presents a simple extension to the ArUco library to generate such user-friendly data, and it provides a performance analysis of this application with static and moving objects, using a smartphone camera to highlight the most notable feature of this solution, but also its limitations
The Streptomyces coelicolor small ORF trpM stimulates growth and morphological development and exerts opposite effects on actinorhodin and calcium-dependent antibiotic production
In actinomycetes, antibiotic production is often associated with a morpho-physiological differentiation program that is regulated by complex molecular and metabolic networks. Many aspects of these regulatory circuits have been already elucidated and many others still deserve further investigations. In this regard, the possible role of many small open reading frames (smORFs) in actinomycete morpho-physiological differentiation is still elusive. In Streptomyces coelicolor, inactivation of the smORF trpM (SCO2038) – whose product modulates L-tryptophan biosynthesis – impairs production of antibiotics and morphological differentiation. Indeed, it was demonstrated that TrpM is able to interact with PepA (SCO2179), a putative cytosol aminopeptidase playing a key role in antibiotic production and sporulation. In this work, a S. coelicolor trpM knock-in (Sco-trpMKI) mutant strain was generated by cloning trpM into overexpressing vector to further investigate the role of trpM in actinomycete growth and morpho-physiological differentiation. Results highlighted that trpM: (i) stimulates growth and actinorhodin (ACT) production; (ii) decreases calcium-dependent antibiotic (CDA) production; (iii) has no effect on undecylprodigiosin production. Metabolic pathways influenced by trpM knock- in were investigated by combining two-difference in gel electrophoresis/nanoliquid chromatography coupled to electrospray linear ion trap tandem mass spectrometry (2D- DIGE/nanoLC-ESI-LIT-MS/MS) and by LC-ESI-MS/MS procedures, respectively. These analyses demonstrated that over-expression of trpM causes an over-representation of factors involved in protein synthesis and nucleotide metabolism as well as a down-representation of proteins involved in central carbon and amino acid metabolism. At the metabolic level, this corresponded to a differential accumulation pattern of different amino acids – including aromatic ones but tryptophan – and central carbon intermediates. PepA was also down-represented in Sco-trpMKI. The latter was produced as recombinant His-tagged protein and was originally proven having the predicted aminopeptidase activity. Altogether, these results highlight the stimulatory effect of trpM in S. coelicolor growth and ACT biosynthesis, which are elicited through the modulation of various metabolic pathways and PepA representation, further confirming the complexity of regulatory networks that control antibiotic production in actinomycetes
On the Suspension Design of Paquitop, a Novel Service Robot for Home Assistance Applications
The general and constant ageing of the world population that has been observed in the last decade has led robotics researchers community to focus its aims to answer the ever-growing demand for health care, housing, care-giving, and social security. Among others, the researchers at Politecnico di Torino are developing a novel platform to enhance the performance offered by present-day issues, and to assess many others which were not even taken into consideration before they have been highlighted by the pandemic emergency currently in progress. This situation, in fact, made dramatically clear how important it is to have reliable non-human operators whom one can trust when the life of elderly or weak patients is endangered by the simple presence of other people. The platform, named Paquitop, features an innovative architecture conceived for omni-directional planar motion. The machine is designed for domestic, unstructured, and variously populated environments. Therefore, the mobile robot should be able to avoid or pass over small obstacles, passing through the capability to achieve specific person tracking tasks, and arriving to the need of operating with an high dynamic performance. Given its purpose, this work addresses the design of the suspension system which enables the platform to ensure a steady floor contact and adequate stability in every using condition. Different configurations of such system are then presented and compared through use-case simulations
results to 5 years after endovenous laser treatment
Introduction: To refer and to discuss the appearance of recurrent varicose veins after many years from the endovenous laser treatment of the refluent saphenous axis. Patients and methods: 191 laser procedures have been carried out in the period between December 2001 and June 2009 at the Center of Phlebolymphology of the Siena University for the treatment of 188 patients with varicose veins of the lower limbs. 145 patients are females and 46 males, ranging in age between 22 and 80 years. The superficial chronic venous insufficiency was caused by the incompetence of the saphenofemoral junction (SFJ) and the reflux of the great saphenous vein (GSV), as demonstrated by duplex scanner. All patients were operated under local anesthesia and sonographic guidance. A diode laser of 810 nm has been used in the first 71 procedures and a diode laser of 980 nm in the following 120 procedures. The fiber laser is introduced for transcutaneous way or after small surgical cutaneous incision from the bottom to the top with the tip that arrives to 2 cm from the saphenofemoral junction, in way to leave effluent the epigastrica vein. The employed parameters have been 12- 14 watt of power with 3 impulses of 1 second according to repeated after an interval of 1 second every cm of length of the vein, thus to obtain a fluence of approximately 40 joule for cm. Results: The immediate obliteration of the saphenous axis has been had in 182 cases (95%). The ricanalization of the great saphenous vein has been documented in the instrumental follow up in 11 patients (10,2%) at 3 years from the treatment, in 9 (12%) at 4 years and in 9 (25,7%) after 5 years. Conclusion: The endovenous laser treatment for the therapy of varicose veins of the lower limbs is a simple procedure, poor invasive, that it can be performed in outpatient or Day Surgery regime without increase of the costs of stay in hospital. Its effectiveness currently is put in argument from the possibility that a recurrent varicose veins appears at distance of years from the treatment with ricanalization of the saphenous axis, even if in absence of symptomatology. In our experience this possibility has evidenced in the clinical and instrumental follow up of the patients operated after 5 years in a percentage that exceeds the 20%
Rehabilitation Machine for Bariatric Individuals
Obesity is known to be growing worldwide. The World Health Organization (WHO) reports that obesity has tripled since 1975. In 2016, 39% of adults over 18 years old were overweight, and 13% were obese. Obesity is mostly preventable by adopting lifestyle improvements, enhancing diet quality, and doing physical exercise. The workload of the physical exercises should be proportionate to the patient’s capabilities. However, it must be considered that obese people are not used to training; they may not endure physical exertion and, even more critically, they could have some psychological impediments to the workouts. Physical exercises and equipment must, therefore, guarantee comfort and prevent situations in which the bariatric individual may feel inadequate. For these reasons, this study aims to design an innovative system to approach simple physical activities, like leg and arm exercises, to bariatric users to enable them to recover mobility and muscle tone gradually. The leading feature of this architecture is the design of hidden exercise mechanisms to overcome the psychological barriers of the users toward these kinds of machines. This paper proposes the initial design of the main sub-systems composing the rehabilitation machine, namely the leg curl and leg extension mechanism and its control architecture, the upper body exercises system, and a series of regulation mechanisms required to accommodate a wide range of users. The proposed functional design will then lead to the development of a prototype to validate the machine
Optimizing the relaxivity of MRI probes at high magnetic field strengths with binuclear GdIIIComplexes
The key criteria to optimize the relaxivity of a Gd(III) contrast agent at high fields (defined
as the region 65 1.5 T) can be summarized as follows: (i) the occurrence of a rotational
correlation time \u3c4R in the range of ca. 0.2\u20130.5 ns; (ii) the rate of water exchange is
not critical, but a \u3c4M < 100 ns is preferred; (iii) a relevant contribution from water
molecules in the second sphere of hydration. In addition, the use of macrocycle-based
systems ensures the formation of thermodynamically and kinetically stable Gd(III)
complexes. Binuclear Gd(III) complexes could potentially meet these requirements. Their
efficiency depends primarily on the degree of flexibility of the linker connecting the two
monomeric units, the absence of local motions and the presence of contribution from
the second sphere water molecules. With the aim to maximize relaxivity (per Gd) over
a wide range of magnetic field strengths, two binuclear Gd(III) chelates derived from
the well-known macrocyclic systems DOTA-monopropionamide and HPDO3A (Gd2L1
and Gd2L2, respectively) were synthesized through a multistep synthesis. Chemical
Exchange Saturation Transfer (CEST) experiments carried out on Eu2L2 at different pH
showed the occurrence of a CEST effect at acidic pH that disappears at neutral pH,
associated with the deprotonation of the hydroxyl groups. Then, a complete 1H and 17O
NMR relaxometric study was carried out in order to evaluate the parameters that govern
the relaxivity associated with these complexes. The relaxivities of Gd2L1 and Gd2L2 (20
MHz, 298 K) are 8.7 and 9.5 mM 121 s 121, respectively, +77% and +106% higher than the
relaxivity values of the corresponding mononuclear GdDOTAMAP-En and GdHPDO3A
complexes. A significant contribution of second sphere water molecules was accounted
for the strong relaxivity enhancement of Gd2L2. MR phantom images of the dinuclear
complexes compared to GdHPDO3A, recorded at 7 T, confirmed the superiority of
Gd2L2. Finally, ab initio (DFT) calculations were performed to obtain information about
the solution structure of the dinuclear complexes
Decoupled motion planning of a mobile manipulator for precision agriculture
Thanks to recent developments in service robotics technologies, precision agriculture (PA) is becoming an increasingly prominent research field, and several studies were made to present and outline how the use of mobile robotic systems can help and improve farm production. In this paper, the integration of a custom-designed mobile base with a commercial robotic arm is presented, showing the functionality and features of the overall system for crop monitoring and sampling. To this aim, the motion planning problem is addressed, developing a tailored algorithm based on the so-called manipulability index, that treats the base and robotic arm mobility as two independent degrees of motion; also developing an open source closed-form inverse kinematics algorithm for the kinematically redundant manipulator. The presented methods and sub-system, even though strictly related to a specific mobile manipulator system, can be adapted not only to PA applications where a mobile manipulator is involved but also to the wider field of assistive robotics
Wheeled Mobile Robots: State of the Art Overview and Kinematic Comparison Among Three Omnidirectional Locomotion Strategies
In the last decades, mobile robotics has become a very interesting research topic in the feld of robotics, mainly because of population ageing and the recent pandemic emergency caused by Covid-19. Against this context, the paper presents an overview on wheeled mobile robot (WMR), which have a central role in nowadays scenario. In particular, the paper describes the most commonly adopted locomotion strategies, perception systems, control architectures and navigation approaches. After having analyzed the state of the art, this paper focuses on the kinematics of three omnidirectional platforms: a four mecanum wheels robot (4WD), a three omni wheel platform (3WD) and a two swerve-drive system (2SWD). Through a dimensionless approach, these three platforms are compared to understand how their mobility is afected by the wheel speed limitations that are present in every practical application. This original comparison has not been already presented by the literature and it can be used to improve our understanding of the kinematics of these mobile robots and to guide the selection of the most appropriate locomotion system according to the specifc application
In Depth Analysis of Power Balance, Handling, and the Traction Subsystem of an Articulated Skid-Steering Robot for Sustainable Agricultural Monitoring
This paper reports on the energy balance test performed on Agri.Q, an eight-wheel articulated robot intended to be a sustainable monitoring tool within the precision agriculture paradigm, and proposes an in-depth analysis of the traction subsystem in order to develop an appropriate traction allocation strategy to improve navigation through hilly or mountainous crops. Tests were conducted on the contribution of the orientable photovoltaic panel to the mission duration and overall sustainability, showing that a suitable mission plan, including dedicated charging phases, could significantly increase the robot’s operating time. A series of simulations of circular trajectories of different curvature and at different longitudinal velocities on flat ground were performed, with the aim of mapping the robot’s behaviour at steady state. The results of the simulations were analysed, paying particular attention to the required torques, manoeuvrability and forces exchanged on the ground. The simulations conducted demonstrated and extended previous results obtained on similar robotic architectures, which suffer from significant understeer behaviour due to significant lateral wheel slip during turning. They also showed the limitations of currently employed traction motors, but also the advantages of a proper traction allocation strategy involving the rear module.
Article highlights.
Agri.Q energy balance tests have been carried out to assess its endurance and sustainability
The traction and handling behaviours of Agri.Q were mapped and discussed in detail in order to improve them
Agri.Q has proven to be a basis for the future implementation of precision agriculture to advance the SDG
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