262 research outputs found

    Modelling of thrombus formation using smoothed particle hydrodynamics method

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    In this paper a novel model, based on the smoothed particle hydrodynamics (SPH) method, is proposed to simulate thrombus formation. This describes the main phases of the coagulative cascade through the balance of four biochemical species and three type of platelets. SPH particles can switch from fluid to solid phase when specific biochemical and physical conditions are satisfied. The interaction between blood and the forming blood clot is easily handled by an innovative monolithic FSI approach. Fluid-solid coupling is modelled by introducing elastic binds between solid particles, without requiring detention and management of the interface between the two media. The proposed model is able to realistically reproduce the thromboembolic process, as confirmed by the comparison of numerical results with experimental data available in the literature

    Students Becoming Supervisors: Student Transformation during a Cross-National, Collaborative Community Engineering Project

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    The Tumaini Innovation Center in Eldoret, Kenya, is an alternative primary and vocational school for former street youth. The DeBoer Lab at Purdue has partnered with Tumaini for the last five years to develop and support integrated engineering activities for the students, which apply their learning to solve problems in their own communities. A Purdue Service Learning Grant project started in November 2018 resulted in the construction of a community gym at Tumaini. A low-cost custom made gym was designed by a team of doctoral and undergraduate students at Purdue in collaboration with Tumaini. In addition to the design and implementation, the project was integrated as a learning opportunity for the Tumaini students. The students were taught 3D modeling principles and prototyping, culminating in teams of students testing the gym equipment they have modeled using a 3D printer. The final implementation integrated the welding and machining skills they are learning, along with the engineering design process and modeling skills. During the final implementation process, three students were involved as welders overseen by a locally appointed technician by the center. As the implementation progressed, one of the students exhibited higher engineering and leadership skills, growing to the role of supervising the project. In this research study, we investigate the experiences of the student leaders at Purdue and Tumaini in their transformation, and how they applied the engineering knowledge in practice. The main factors that led the Purdue and Tumaini student to take on a leadership role were to gain experience in the field, to demonstrate their ability, and the level of self-confidence and the confidence that their mentors had in the

    Arbuscular mycorrhizal fungi altered the hypericin, pseudohypericin, and hyperforin content in flowers of Hypericum perforatum grown under contrasting P availability in a highly organic substrate

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    St. John’s Wort (Hypericum perforatum) is a perennial herb able to produce water-soluble active ingredients (a.i.), mostly in flowers, with a wide range of medicinal and biotechnological uses. However, information about the ability of arbuscular mycorrhizal fungi (AMF) to affect its biomass accumulation, flower production, and concentration of a.i. under contrasting nutrient availability is still scarce. In the present experiment, we evaluated the role of AMF on growth, flower production, and concentration of bioactive secondary metabolites (hypericin, pseudohypericin, and hyperforin) of H. perforatum under contrasting P availability. AMF stimulated the production of aboveground biomass under low P conditions and increased the production of root biomass. AMF almost halved the number of flowers per plant by means of a reduction of the number of flower-bearing stems per plant under high P availability and through a lower number of flowers per stem in the low-P treatment. Flower hyperforin concentration was 17.5% lower in mycorrhizal than in non-mycorrhizal plants. On the contrary, pseudohypericin and hypericin concentrations increased by 166.8 and 279.2%, respectively, with AMF under low P availability, whereas no effect of AMF was found under high P availability. These results have implications for modulating the secondary metabolite production of H. perforatum. However, further studies are needed to evaluate the competition for photosynthates between AMF and flowers at different nutrient availabilities for both plant and AM fungus

    Healthcare Professionals’ Perceptions and Concerns towards Domestic Violence during Pregnancy in Southern Italy

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    Background: Literature on pregnancy highlighted a large number of women abused by their partners, especially among low-income teenagers attending hospital for pregnancy check-ups. Pregnancy represents a key moment for diagnosing domestic violence. Method: This study explores health professionals’ perceptions and concerns about domestic violence against women in services dealing with pregnant women. The twenty-four interviewees were from an Obstetrical-Gynecological walk-in Clinic in the south of Italy. The textual data has been complementarily analyzed by means of two dierent procedures: Symbolic-structural semiotic analysis and Thematic content analysis. Results: What emerges is that the interviewees of the clinic do not regard the issue of domestic violence as a matter of direct interest for the health service. The clinic is seen as a place for urgent contact, but one where there is not enough time to dedicate to this kind of patient, nor an adequate space to care for and listen to them. Obstetricians and health personnel expressed a negative attitude when it comes to including questions regarding violence and abuse in pre-natal reports. Training for health and social professionals and the empowering of institutional support and networking practices are needed to increase awareness of the phenomenon among the gynecological personnel

    Tumor-associated and immunochemotherapy-dependent long-term alterations of the peripheral blood NK cell compartment in DLBCL patients

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    Natural Killer (NK) cells are a key component of tumor immunosurveillance and thus play an important role in rituximab-dependent killing of lymphoma cells via an antibody-dependent cellular cytotoxicity (ADCC) mechanism. We evaluated the phenotypic and functional assets of peripheral blood NK cell subsets in 32 newly-diagnosed diffuse large B-cell lymphoma (DLBCL) patients and in 27 healthy controls. We further monitored long-term modifications of patient NK cells for up to 12 months after rituximab-based immunochemotherapy. At diagnosis, patients showed a higher percentage of CD56dim and CD16C NK cells, and a higher frequency of GrzBC cells in CD56dim, CD56bright, and CD16C NK cell subsets than healthy controls. Conversely, DLBCL NK cell killing and interferon g (IFNg) production capability were comparable to those derived from healthy subjects. Notably, NK cells from refractory/relapsed patients exhibited a lower “natural” cytotoxicity. A marked and prolonged therapy-induced reduction of both “natural” and CD16- dependent NK cytotoxic activities was accompanied by the down-modulation of CD16 and NKG2D activating receptors, particularly in the CD56dim subset. However, reduced NK cell killing was not associated with defective lytic granule content or IFNg production capability. This study firstly describes tumor-associated and therapy-induced alterations of the systemic NK cell compartment in DLBCL patients. As these alterations may negatively impact rituximab-based therapy efficacy, our work may provide useful information for improving immunochemotherapeutic strategies

    A Novel Member of the Bacterial-Archaeal Regulator Family Is a Nonspecific DNA-binding Protein and Induces Positive Supercoiling

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    In hyperthermophilic Archaea genomic DNA is from relaxed to positively supercoiled in vivo because of the action of the enzyme reverse gyrase, and this peculiarity is believed to be related to stabilization of DNA against denaturation. We report the identification and characterization of Smj12, a novel protein of Sulfolobus solfataricus, which is homologous to members of the so-called Bacterial-Archaeal family of regulators, found in multiple copies in Eubacteria and Archaea. Whereas other members of the family are sequence-specific DNA- binding proteins and have been implicated in transcriptional regulation, Smj12 is a nonspecific DNA-binding protein that stabilizes the double helix and induces positive supercoiling. Smj12 is not abundant, suggesting that it is not a general architectural protein, but rather has a specialized function and/or localization. Smj12 is the first protein with the described features identified in Archaea and might participate in control of superhelicity during DNA transactions

    Screening for Tuberculosis in Health Care Workers. Experience in an Italian Teaching Hospital

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    Health care workers (HCW) are particularly at risk of acquiring tuberculosis (TB), even in countries with low TB incidence. Therefore, TB screening in HCW is a useful prevention strategy in countries with both low and high TB incidence. Tuberculin skin test (TST) is widely used although it suffers of low specificity; on the contrary, the in vitro enzyme immunoassay tests (IGRA) show superior specificity and sensitivity but are more expensive. The present study reports the results of a three-year TB surveillance among HCW in a large teaching hospital in Rome, using TST (by standard Mantoux technique) and IGRA (by QuantiFERON-TB) as first- and second-level screening tests, respectively. Out of 2290 HCW enrolled, 141 (6.1%) had a positive TST; among them, 99 (70.2%) underwent the IGRA and 16 tested positive (16.1%). The frequency of HCW tested positive for TB seems not far from other experiences in low incidence countries. Our results confirm the higher specificity of IGRA, but, due to its higher cost, TST can be considered a good first level screening test, whose positive results should be further confirmed by IGRA before the patients undergo X-ray diagnosis and/or chemotherapy

    Increasing Transparency of Reinforcement Learning using Shielding for Human Preferences and Explanations

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    The adoption of Reinforcement Learning (RL) in several human-centred applications provides robots with autonomous decision-making capabilities and adaptability based on the observations of the operating environment. In such scenarios, however, the learning process can make robots' behaviours unclear and unpredictable to humans, thus preventing a smooth and effective Human-Robot Interaction (HRI). As a consequence, it becomes crucial to avoid robots performing actions that are unclear to the user. In this work, we investigate whether including human preferences in RL (concerning the actions the robot performs during learning) improves the transparency of a robot's behaviours. For this purpose, a shielding mechanism is included in the RL algorithm to include human preferences and to monitor the learning agent's decisions. We carried out a within-subjects study involving 26 participants to evaluate the robot's transparency in terms of Legibility, Predictability, and Expectability in different settings. Results indicate that considering human preferences during learning improves Legibility with respect to providing only Explanations, and combining human preferences with explanations elucidating the rationale behind the robot's decisions further amplifies transparency. Results also confirm that an increase in transparency leads to an increase in the safety, comfort, and reliability of the robot. These findings show the importance of transparency during learning and suggest a paradigm for robotic applications with human in the loop
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