Planetary landing: modelling and control of the propulsion descent

In the propulsive phase, after parachute release, of planetary landing like Mars or Moon, horizontal motion is obtained by tilting the axial thrust, so that it aligns either to the negative velocity vector (gravity turn) or to the requested acceleration vector. The latter strategy is assumed here, as it allows pinpoint landing. As such, tilt angles (pitch and yaw) become proportional to the horizontal acceleration. Instead of designing a hierarchical guidance and control in which horizontal acceleration becomes the attitude control target, a unique control system can be designed based on the fourth order dynamics from angular acceleration to position. The paper shows that the combined dynamics can be (quasi) input-state linearized except the nonlinear factor of the tilt angles (the axial thrust imposed by vertical braking). The paper shows that control design around the reference trajectory (tilt and position) given by the guidance can exploit the quasi linearization, but tracking error stability must be proved in presence of a not stabilizable external disturbance. The paper is restricted to closed-loop control strategies, and their effectiveness is proved through Monte Carlo simulations

A software-based self test of CUDA Fermi GPUs

Nowadays, Graphical Processing Units (GPUs) have become increasingly popular due to their high computational power and low prices. This makes them particularly suitable for high-performance computing applications, like data elaboration and financial computation. In these fields, high efficient test methodologies are mandatory. One of the most effective ways to detect and localize hardware faults in GPUs is a Software-Based-Self-Test methodology (SBST). In this paper a fully comprehensive SBST and fault localization methodology for GPUs is presented. This novel approach exploits different custom test strategies for each component inside the GPU architecture. Such strategies guarantee both permanent fault detection and accurate fault localization

Increasing the robustness of CUDA Fermi GPU-based systems

Nowadays Graphical processing Units (GPUs) have become increasingly popular due to their high computational power and low prices. This makes them particularly suitable for high-performance computing applications, like data elaboration and image processing. In these fields, the capability of properly work even in presence of faults is mandatory. This paper presents an innovative approach, that combines a Software Based Self Test & Diagnosis (SBSTD) methodology with a fault mitigation strategy, to increase the robustness of a CUDA Fermi GPU-based system

Lupus mastitis in male mimicking a breast lump

A 43-year-old male, with a 3-month history of a left breast lump underwent clinical evaluation in our Institute. This solid and irregular mass measured 2 2 cm and was located at the upper lateral quadrant with no skin changes. There were no inflammatory signs. However, a lymphadenopathy was presented with a mobile ipsilateral axillary node 1.5 cm in diameter. Computerized tomography demonstrated a hyperplastic lateral cervical lymph nodes reactio

Optical properties of two-dimensional tin nanosheets epitaxially grown on graphene

Heterostacks formed by combining two-dimensional materials show novel properties which are of great interest for new applications in electronics, photonics and even twistronics, the new emerging field born after the outstanding discoveries on twisted graphene. Here, we report the direct growth of tin nanosheets at the two-dimensional limit via molecular beam epitaxy on chemical vapor deposited graphene on Al2O3(0001). The mutual interaction between the tin nanosheets and graphene is evidenced by structural and chemical investigations. On the one hand, Raman spectroscopy indicates that graphene undergoes compressive strain after the tin growth, while no charge transfer is observed. On the other hand, chemical analysis shows that tin nanosheets interaction with sapphire is mediated by graphene avoiding the tin oxidation occurring in the direct growth on this substrate. Remarkably, optical measurements show that the absorption of tin nanosheets show a graphene-like behavior with a strong absorption in the ultraviolet photon energy range, therein resulting in a different optical response compared to tin nanosheets on bare sapphire. The optical properties of tin nanosheets therefore represent an open and flexible playground for the absorption of light in a broad range of the electromagnetic spectrum and technologically relevant applications for photon harvesting and sensors.Comment: 14 pages, 7 figure

Endocarditis of Native Valve due to Proteus mirabilis: Case Report and Literature Review

AbstractEndocarditis due to Proteus mirabilis is very uncommon and the optimal surgical and/or antibiotic treatment is not well defined. Guidelines from the AHA and ESC recommend prolonged courses of combined antibiotic therapy but information regarding the clinical presentation, the choice of treatment, the surgical management, and the duration of therapy can only be taken from clinical cases reported in literature. We describe a case of native valve endocarditis due to Proteus mirabilis, successfully treated with antibiotic therapy alone with a review of the relevant literature on this topic

Surgical closure of chest wall in noninflammatory locally advanced breast carcinoma with ulceration of the skin.

Abstract:  Patients with noninflammatory locally advanced breast cancer with ulceration of skin or muscle or parietal wall infiltration, better named "extended locally advanced breast cancer," may require cancer surgery and plastic reconstruction of the chest wall after multidisciplinary evaluation. The decision is made to improve quality of life, independently of prognosis, and severity of the disease. The aim of this study is to evaluate the best method for surgical closure of the chest wall and to check whether ablative surgery is an appropriate procedure in regards to the treatment of cancer. From October 1997 to June 2006, 27 patients with noninflammatory extended locally advanced breast cancer with ulceration of the skin, who were not candidate or did not respond to a neo-adjuvant treatment, underwent radical mastectomy and reconstructive surgery. Sixteen patients (59%) were affected by primary tumors of the breast, and eleven patients (41%) had local recurrence after mastectomy or conservative breast surgery. Two main techniques were used for breast reconstruction: transverse rectus-abdominis musculo cutaneous flap in 19 patients (70%), and a fasciocutaneous flap in eight patients (30%). The best procedure in each patient was chosen according to the extent of skin loss or previous radiotherapy to the chest wall. Fourteen patients (52%) died during the follow-up and the median length of survival was 16 months (range 3–79) in transverse rectus-abdominis musculo cutaneous group and 4 months (range 2–23) in fasciocutaneous flap group. The median length of follow-up after treatment for patients still alive was 32.5 months (range 0–96) in transverse rectus-abdominis musculo cutaneous flap group, and 18 months (range 8–41) in fasciocutaneous flap group. At the end of the follow-up, 10 patients were alive without evidence of disease and three patients developed metastatic lesion or local recurrence. The longest recorded disease free interval for a patient still alive and tumor free was 96 months. Only three patients (11%) had local complications: two wound infections and one partial necrosis of the transverse rectus-abdominis musculo cutaneous flap. Median hospital stay was 7 days (range 3–13) for transverse rectus-abdominis musculo cutaneous and 6 days (range 3–13) for fasciocutaneous flap. Our results confirmed that transverse rectus-abdominis musculo cutaneous group and fasciocutaneous flap flaps are good reconstructive options in patients with extended locally advanced breast cancer. Quality of life has improved in this group of patients, with acceptable survival periods and in some cases very important survival rates

Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots.

Microorganisms move in challenging environments by periodic changes in body shape. In contrast, current artificial microrobots cannot actively deform, exhibiting at best passive bending under external fields. Here, by taking advantage of the wireless, scalable and spatiotemporally selective capabilities that light allows, we show that soft microrobots consisting of photoactive liquid-crystal elastomers can be driven by structured monochromatic light to perform sophisticated biomimetic motions. We realize continuum yet selectively addressable artificial microswimmers that generate travelling-wave motions to self-propel without external forces or torques, as well as microrobots capable of versatile locomotion behaviours on demand. Both theoretical predictions and experimental results confirm that multiple gaits, mimicking either symplectic or antiplectic metachrony of ciliate protozoa, can be achieved with single microswimmers. The principle of using structured light can be extended to other applications that require microscale actuation with sophisticated spatiotemporal coordination for advanced microrobotic technologies.This work was in part supported by the European Research Council under the ERC Grant agreements 278213 and 291349, and the DFG as part of the project SPP 1726 (microswimmers, FI 1966/1-1). SP acknowledges support by the Max Planck ETH Center for Learning Systems.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nmat456

Impact of antimicrobial stewardship interventions on appropriateness of surgical antibiotic prophylaxis. How to improve

Background and Objectives: Surgical Site Infections (SSIs) are the most common healthcare-associated infections and represent a major clinical problem in terms of mortality, morbidity, length of stay and overall costs. The appropriateness of Surgical Antibiotic Prophylaxis (SAP) is a key component to reduce the SSIs while the inappropriateness is a major cause of some emerging infections and selection of antibiotic resistance, therefore increasing healthcare costs. For this reasons international and national guidelines have been developed to guide clinicians in the optimal use of SAP. The The overall compliance to these guidelines is poor, with a high heterogeneity and as a consequence there is no universally recognized intervention to improve the appropriateness of SAP. The antimicrobial stewardship program is a systematic approach to improve appropriateness of antimicrobial use, to optimize the treatment of infections and to minimize the adverse effects associated with antibiotic use, like antimicrobial resistance, toxicity and costs. We describe a successfully Antimicrobial Stewardship (AMS) intervention on SAP appropriateness. Material and Methods: The prospective study was conducted at “Santa Maria” tertiary hospital in Terni, Umbria, in 12 main surgical units and was organized in three subsequent phases . The hospital defined evidence-based guidelines for optimal use of SAP, approved a new workflow to optimize the process of ordering, dispensing, administering and documenting SAP and created a satellite pharmacy in the operative block . Phase 1: we analysed 2059 elective surgical cases from January to June 2018 for 3 SAP parameters of appropriateness: indication, choice, dose. Phase 2: in July 2018 an audit was performed to analyse the result ; we reviewed 1781 elective surgical procedures from July to December 2018 looking for the same 3 SAP parameters of appropriateness. Results: The comparative analysis between phase 1 and 2 has demonstrated that the correct indication has a significant improvement (p-value 0.00128), moving from 73.63% in phase 1 to 77.82% in phase 2. The choice of antibiotic has not shown any significant improvement (p-value 0.4863) . The correct dose significantly improved (p-value< 2.2 1016 ), rising from 71.75% in phase 1 to 86.19% in phase 2. The overall compliance had a significant improvement (p-value <5.6 1012) passing from 40.21% in tphase 1 to 51.15% in phase 2. Conclusions: Our prospective study demonstrated a model of succesfully antimicrobial stewardship intervention that improves appropriateness of SAP