Showing papers by "University of Siena published in 2022"

A comprehensive survey on ‘circular polarized antennas’ for existing and emerging wireless communication technologies

Abstract: Circular polarized (CP) antennas are well suited for long-distance transmission attainment. In order to be adaptable for beyond 5G communication, a detailed and systematic investigation of their important conventional features is required for expected enhancements. The existing designs employing millimeter wave, microwave, and ultra-wideband frequencies form the elementary platform for future studies. The 3.4 to 3.8 GHz frequency band has been identified as a worthy candidate for 5G communications because of spectrum availability. This band comes under ultra-wideband frequencies (3.1 to 10.6 GHz). In this survey, a review of CP antennas in the selected areas to improve the understanding of early-stage researchers specially experienced antenna designers has presented for the first time as best of our knowledge. Design implementations involving size, axial ratio, efficiency, and gain improvements are covered in detail. Besides that, various design approaches to realize CP antennas including (i) printed CP antennas based on parasitic or slotted elements, (ii) dielectric resonator CP antennas, (iii) reconfigurable CP antennas, (iv) substrate integrated waveguide (SIW) CP antennas, (v) fractal CP antennas, (vi) hybrid techniques CP antennas, and (vii) 3-D printing CP antennas with single and multiple feeding structures have investigated and analyzed. The aim of this work is to provide necessary guidance for the selection of CP antenna geometries in terms of the required dimensions, available bandwidth, gain, and useful materials for the integration and realization in future communication systems.

Flexible scheduling and tactile communication for human–robot collaboration

Abstract: Human–robot collaboration (HRC) is expected to add flexibility and agility to production lines in manufacturing plants. In this context, versatile scheduling algorithms are needed to organize the increasingly complex work-flow and to exploit the gained flexibility, ensuring the optimal use of resources and the smart management of failures. Moreover, intuitive user interfaces are needed to communicate with the human worker, informing him/her of the next operation to perform. Usually, grounded or wearable screens are used to this aim. Whenever human sight is impaired or needs to be free, other sensory channels could be used as well. In this work, we present a new dynamic scheduler that adapts to the system variability, and a novel way of communicating instructions to the human operators based on haptic guidance. The proposed strategies were applied to a complex assembly task involving three agents and compared to baseline methods with an experimental campaign involving 16 subjects. Results show the clear advantage of using dynamic scheduling over the static one and suggest that a combination of visual and tactile stimuli is a viable and effective solution for displaying instructions in complex HRC scenarios.

Signet ring cell percentage in poorly cohesive gastric cancer patients: A potential novel predictor of survival

Abstract: Signet ring cells (SRC) are widely acknowledged as a prognostically unfavorable histotype amongst poorly cohesive gastric cancer. In this study we evaluated the impact of SRC percentage on the clinical, pathological and prognostic features of these tumors according to the classification by the European Chapter of the IGCA.We retrospectively reviewed records of patients with poorly cohesive gastric cancer that underwent surgery between 1995 and 2016, whose tissue specimens were available in a biological bank. All slides were put under revision, patients were reclassified into three groups according to the proportion of signet ring cells: "pure" SRC (containing ≥90% of SRCs), Poorly Cohesive-Not Otherwise Specified (PC-NOS) (containing ≤10% of SRCs), and PC-NOS/SRC (containing <90% but >10% of SRCs). The clinicopathological factors between different types were analyzed and prognostic differences were compared.Among 143 enrolled patients, 51% were male and 49% were female. The mean (±SD) age at diagnosis was 61 ± 13.9 years. Eighty-seven patients (60.8%) were reclassified as PC-NOS, 56 (39.2%) as PC-NOS/SRC and none as "pure" SRC. Five-years overall survival was significantly higher in PC-NOS/SRC group (63.3%) compared with PC-NOS group (12.7%). The increase in mortality risk was more than four-fold in patients with PC-NOS pattern compared to those with PC-NOS/SRC (HR 4.32 [95% CI 2.5-7.4]. After adjustment for potential confounding factors, SRC pattern was still an independent predictor of survival.The percentage of SRCs is inversely related to tumor aggressiveness, confirming the role of SRC pattern as an independent predictor of survival.

Adherence to Mediterranean diet, physical activity level, and severity of periodontitis: Results from a university‐based cross‐sectional study

Abstract: The aim of this study was to evaluate the association between adherence to Mediterranean diet (MD) and physical activity (PA) level with the periodontal status of a University-based cohort of individuals.A total of 235 individuals were included in the study. MD adherence and PA level were registered through validated questionnaires, together with a full periodontal examination. Crude and adjusted odds ratios (ORs) [95% confidence interval] were calculated to evaluate the association between MD adherence, PA level, and periodontitis severity. A final logistic multivariate regression model was built to evaluate the impact of the combination between low MD adherence and low PA level on the prevalence of Stage III/IV periodontitis.The adjusted ORs for Stage III/IV periodontitis were 1.65 [0.84 to 3.28; P = 0.42] for low PA and 5.63 [3.21 to 9.84; P = 0.00] for low MD adherence. The final logistic multivariate regression model resulted in OR = 10.23 [4.01, 26.09; P = 0.00] of having Stage III/IV periodontitis in individuals with low MD adherence and low PA.Individuals conducting a lifestyle characterized by the combination of low MD adherence and lack of regular exercise had 10 times the odds to have severe forms of periodontitis.

Shape Deformation, Budding and Division of Giant Vesicles and Artificial Cells: A Review

Abstract: The understanding of the shape-change dynamics leading to the budding and division of artificial cells has gained much attention in the past few decades due to an increased interest in designing stimuli-responsive synthetic systems and minimal models of biological self-reproduction. In this respect, membranes and their composition play a fundamental role in many aspects related to the stability of the vesicles: permeability, elasticity, rigidity, tunability and response to external changes. In this review, we summarise recent experimental and theoretical work dealing with shape deformation and division of (giant) vesicles made of phospholipids and/or fatty acids membranes. Following a classic approach, we divide the strategies used to destabilise the membranes into two different types, physical (osmotic stress, temperature and light) and chemical (addition of amphiphiles, the addition of reactive molecules and pH changes) even though they often act in synergy when leading to a complete division process. Finally, we review the most important theoretical methods employed to describe the equilibrium shapes of giant vesicles and how they provide ways to explain and control the morphological changes leading from one equilibrium structure to another.

Electromyographic Assessment of Masseter Muscle Activity: A Proposal for a 24 h Recording Device with Preliminary Data

Abstract: Objective: The instrumental measurement of electromyographic (EMG) activity in the natural environment is the best strategy available to collect information on bruxism. The twofold aim of this study was to (1) introduce and discuss a novel EMG device for the assessment of awake (AB) and sleep bruxism (SB) in the home environment over 24 h and (2) present some preliminary data. Methods: Fifteen healthy volunteers (eight males and seven females; mean age: 48.2 ± 4.1 years) underwent 24 h EMG recording trials of their masseter muscle activity (MMA) with a miniaturized wireless device. This device allowed us to measure the durations of the different phases of the recordings (total duration, awake time, sleep time, and electrode dislodgement time) as well as the bruxism time index (BTI) and bruxism work index (BWI) for both the waking and sleeping hours. Results: For the healthy volunteers, on average, the bruxism work index (BWI) values were 0.4 ± 0.2 and 0.1 ± 0.1 for awake and sleep, respectively, while the mean bruxism time index (BTI) values were 0.9 ± 0.5 for awake and 0.3 ± 0.1 for sleep. Conclusions: This investigation describes the technical features of a novel EMG recording device that permits the evaluation of masseter muscle activity in the home environment over 24 h. For the first time, a dedicated elaboration of the EMG signal allowed an assessment of muscle work and not just a count of purported SB/EMG events. Clinical significance: Based on the multidisciplinary approach in the study of bruxism, such a methodology, thanks to its peculiar features, will allow researchers and clinicians to monitor the epidemiology of MMA and delve deeper into the awake and sleep bruxism correlates for tailored management in clinical settings.

Physiological adaptations affecting drug pharmacokinetics in space: what do we really know? A critical review of the literature

Abstract: As human spaceflight progresses with extended mission durations, the demand for effective and safe drugs will necessarily increase. To date, the accepted medications used during missions (for space motion sickness, sleep disturbances, allergies, pain, and sinus congestion) are administered under the assumption that they act as safely and efficaciously as on Earth. However, physiological changes have been documented in human subjects in spaceflight involving fluid shifts, muscle and bone loss, immune system dysregulation, and adjustments in the gastrointestinal tract and metabolism. These alterations may change the pharmacokinetics (PK) and pharmacodynamics of commonly used medications. Frustratingly, the information gained from bed rest studies and from in-flight observations is incomplete and also demonstrates a high variability in drug PK. Therefore, the objectives of this review are to report (i) the impact of the space environmental stressors on human physiology in relation to PK; (ii) the state-of-the-art on experimental data in space and/or in ground-based models; (iii) the validation of ground-based models for PK studies; and (iv) the identification of research gaps.

Podcasting as a hybrid cultural form between old and new media

Abstract: In this chapter, I propose a way out of this debate, a third way which draws upon the cultural history of broadcasting, the political economy of communication, Social Construction of Technology studies (SCOT), Actor-Network Theory (ANT), and Cultural Studies to explore the very nature of podcasting as a medium. Comparing the early years of broadcasting with the early stage of podcasting, I will try to show that podcasting has re-mediated some aspects of radio, but it also represents something completely different. I will account for this ‘hybrid’ nature of podcasting’s cultural form: podcasting should not be intended solely as a media object (the podcast episode) nor as a distribution technology (the .rss format, the podcast networks or the podcast streaming platforms), but as a new, hybrid, cultural form, that draws not only from radio, but also from theatre, performing arts, design, and internet culture.

The Antarctic Continent in Gondwana: a perspective from the Ross Embayment and Potential Research Targets for Future Investigations

Abstract: After a description of the main geological units and the present-day geotectonic setting before Gondwana amalgamation, this chapter summarises the tectonic evolution of the Antarctic continent from its inclusion as part of the Gondwana supercontinent to the breakup of this landmass and the repositioning of Antarctica at southern polar latitudes since the Early Cretaceous. The geological evolution of the Antarctic continent is then described considering two main time periods: (1) c. 600–450 Ma, covering the processes which were active immediately before and during the amalgamation of Gondwana; and (2) c. 450–180 Ma, including all the major events that occurred after the final stage of Gondwana amalgamation to the time immediately before the Gondwana breakup phase. A subsequent section is devoted to the 180 Ma to recent time window during which present-day Antarctica and the other southern continents and surrounding oceanic basins formed as consequence of the fragmentation of Gondwana, and when tectonic processes led to the drift and dispersion of the various continental fragments. After a general overview of the most significant plate tectonic stages, and coeval magmatic products, the chapter reviews the main geological findings from the Ross Embayement region – one of the most investigated regions in Antarctica – the Transantarctic Mountains and the Ross Sea sector of the Western Antarctic Rift System. Persistent open problems, and potential research themes, are discussed in the Conclusions.

Vehicle stability controller HiL validation on static simulator

Abstract: Abstract In the automotive world, Hardware in the Loop (HiL) methodologies are used to speed up the design and calibration process of the various mechatronics components installed on the vehicle. Installing production parts on advanced driving simulator enables the performance assessment in realistic scenarios, including a test driver earlier in the design process. The scope of this work is to evaluate the effect of ABS and ESC system, replicating their influence on the steering wheel. A brake by wire production system has been installed on a static simulator, equipped with a EPSiL steering bench, capable of accurately replicate tie-rod forces on a production steering unit. Full brake, sine steer maneuvers have been carried out both on real vehicle and on virtual environment. The system showed its capabilities of replicating the same functionalities of the real vehicle, extending the static simulator potentialities to support the activities on calibration and test of vehicle systems.

Brief Communication PD1-related Nephrotoxicity: Optimizing Its Clinical Management Through Histopathologic Features

Abstract: Immune-related nephrotoxicity (ir-N) is a rare adverse event of immune-checkpoint(s) inhibitors (ICI) therapy and its clinical management is still debated. Among 501 consecutive ICI-treated patients at our Institution, 6 who developed an ir-N with clinical signs suggestive for an acute kidney injury underwent kidney biopsy. Histology showed an acute tubule-interstitial nephritis, simulating the scenario of acute T-cell–mediated kidney transplant rejection. Thus, the management of allograft kidney rejection routinely utilized at our clinic was implemented, leading to rapid renal function improvement. Histologic features supporting the definition of an immune-mediated acute kidney injury in ICI-treated patients may help optimizing the clinical management of ir-N.

From growth goals to proactive organizational resilience: first evidence in women-led and non-women-led Italian wineries

Abstract: Abstract In a fast-changing world, characterized by evenly unexpected challenges and shocks, being resilient is a crucial aspect for every organization. Drawing from the goal setting theory and the double standards of competence perspective, this study aims at understanding the antecedents of organizational proactive resilience. More precisely, it looks at the impact of quantitative and qualitative organizational growth goals on proactive resilience, distinguishing between women-led and non-women-led firms. Based on a unique sample of 167 Italian wineries (67 women-led and 100 non-women-led), this paper tests this theoretical model using path analysis techniques. The wine sector is a particularly interesting context to study the phenomenon due to its exposure to natural disasters, new consumers’ behaviours that are requiring firms to continuously innovate and differentiate in a traditionally low-tech sector, but also changes happening at wineries’ management level. In fact, the sector has been traditionally male dominated, but women are increasingly taking the lead. The findings indicate that growth goals differently contribute to proactive organizational resilience, but their effects vary in women- and non-women-led businesses. Specifically, these results suggest that in women-led wineries, proactive organizational resilience depends on quantitative growth goals while in non-women-led wineries businesses this depends on qualitative growth goals.

KEYNOTE-022: Pembrolizumab with trametinib in patients with BRAF wild-type melanoma or advanced solid tumours irrespective of BRAF mutation

Abstract: Parts 4 and 5 of the phase 1/2 KEYNOTE-022 study investigated the maximum tolerated dose (MTD), safety, and efficacy of pembrolizumab plus trametinib in solid tumours and BRAF wild-type melanoma.Patients received intermittent or concurrent dosing of pembrolizumab plus trametinib. Concurrent dosing was 2 or 4 weeks of trametinib run-in followed by concurrent pembrolizumab every 3 weeks (Q3W) plus trametinib once daily (QD). Intermittent dosing was 2 weeks of trametinib run-in followed by pembrolizumab plus intermittent trametinib (1 week off/2 weeks on). A 3 + 3 dose escalation was used, followed by dose confirmation.Forty-two patients were enrolled. No dose-limiting toxicities (DLTs) occurred at initial dose levels (DL). At subsequent DLs, 10 of 38 evaluable patients had DLTs. For concurrent dosing, MTD was pembrolizumab 200 mg Q3W plus trametinib 1.5 mg QD, with a 2-week trametinib 1.5 mg QD run-in (concurrent DL2a); in concurrent DL2a group, five (31%) patients had grade 3/4 treatment-related adverse events (TRAEs); the objective response rate (ORR) was 0%. ORR was 40% in concurrent DL1 and 0% in concurrent DL2b. For intermittent dosing, MTD was pembrolizumab 200 mg Q3W plus trametinib 2 mg QD with a 2-week trametinib 2 mg QD run-in (intermittent DL2); in the intermittent DL2 group, seven (47%) patients had grade 3/4 TRAEs; ORR was 27%. ORR in intermittent DL1 was 33%.MTDs for concurrent and intermittent dosing of pembrolizumab with trametinib were identified. The combination had limited antitumour activity, numerically higher ORR with intermittent versus concurrent dosing, and manageable safety. CLINICALTRIALS.NCT02130466.