1,350 research outputs found

    Effective continuum models for the buckling of non-periodic architected sheets that display quasi-mechanism behaviors

    Full text link
    In this work, we construct an effective continuum model for architected sheets that are composed of bulky tiles connected by slender elastic joints. Due to their mesostructure, these sheets feature quasi-mechanisms -- low-energy local kinematic modes that are strongly favored over other deformations. In sheets with non-uniform mesostructure, kinematic incompatibilities arise between neighboring regions, causing out-of-plane buckling. The effective continuum model is based on a geometric analysis of the sheets' unit cells and their energetically favorable modes of deformation. Its major feature is the construction of a strain energy that penalizes deviations from these preferred modes of deformation. The effect of non-periodicity is entirely described through the use of spatially varying geometric parameters in the model. Our simulations capture the out-of-plane buckling that occurs in non-periodic specimens and show good agreement with experiments. While we only consider one class of quasi-mechanisms, our modeling approach could be applied to a diverse set of shape-morphing systems that are of interest to the mechanics community

    Towards the Automated Coverlay Assembly in FPCB Manufacturing: Concept and Preliminary Tests

    Get PDF
    AbstractIn modern electronics, flexible and rigid-flex PCBs are largely used due to their intrinsic versatility and performance, allowing to increase the available volume, or enabling connection between unconstrained components. Rigid-flex PCBs consists of rigid board portions with flexible interconnections and are commonly used in a wide variety of industrial applications. However, the assembly process of these devices still has some bottlenecks. Specifically, they require the application of cover layers (namely, coverlays), to provide insulation and protection of the flexible circuits. Due to the variability in planar shape and dimensions, the coverlay application is still performed manually, requiring troublesome manipulation steps and resulting in undetermined time-cycle and precision.This paper aims at the improvement of the industrial process currently performed, by proposing an approach for the automation of Kapton coverlay manipulation and application. Since these products are commercially provided as a film with a protective layer to be removed, the peeling issue is addressed, representing a challenging step of the automated process; the results of a systematic series of tests, performed in order to validate the peeling strategy, are reported in the paper. The overall assembly strategy relies on the development of a customized multi-hole vacuum gripper, whose concept is presented and contextualized in the proposed assembly process by outlining a suitable workcell architecture

    Sex Differences on Mitotane Concentration and Treatment Outcome in Patients with Adrenocortical Carcinoma

    Get PDF
    (1) Background: In clinical settings, data regarding sex are rarely investigated. In women, factors such as body size and composition, hormonal variations, metabolism, and access to care systems and therapy could strongly influence the pharmacological management and the outcome of the therapy. To underline this sex-related difference, we retrospectively collected data from adrenocortical carcinoma patients treated with mitotane, and then evaluated sex-related pharmacokinetics parameters. (2) Methods: A fully validated chromatographic method was used to quantify mitotane concentration in plasma collected from adult patients, also considering the active metabolite ortho,para,dichlorodiphenylethene (o,p′-DDE). Statistical analyses were used to evaluate the sex influence on drugs pharmacokinetics. (3) Results: We found that sex resulted as predictive factor of plasma mitotane and o,p′-DDE concentrations and significantly influenced the attainment of the therapeutic target of mitotane, implying that female sex could be a risk factor of treatment failure. (4) Conclusions: These results suggest that mitotane therapy should be modulated according to patient sex. Furthermore, the proposed approach could contribute to facilitating and disseminating sex-specific pharmacology

    A simple and accurate allometric model to predict single leaf area of twenty-one European apricot cultivars

    Get PDF
    Research in fruit tree physiology and breeding often requires accurate and non-destructive methods for estimating leaf area (LA). The development of unbiased allometric model from linear measurements [leaf length (L) and/or width (W)] to predict individual LA of apricot irrespective of cultivars is still lacking. The models were built using LA, L, and W data measured in 3,040 leaves collected on trees of nineteen apricot cultivars (calibration experiment). Model(s) were validated on 520 apricot leaves collected from the trees of two additional cultivars (validation experiment). LA prediction models based only on L measurements (L or L2) were not suitable for estimating LA of apricot. A significant improvement in LA prediction was observed when the model including W2 as an independent variable was adopted. However, the coefficients of one dimension LA model (W2) were affected by leaf shape (L:W ratio) and consequently were excluded. To develop an accurate LA model for apricot, independent of leaf shape groups, the product L×W was used as an independent variable. The linear model LA = 1.193 + 0.668 (L×W) exhibited the highest R2, the smallest mean square error (MSE) and predicted residual error sum of squares (PRESS). In the model validation, correlation coefficients showed that there was a highly reliable relationship between the predicted and the observed LA values, giving an underestimation of 2.9% in the prediction. The LA model using LW as independent variable can be successfully adopted in research on apricot, since it provides an accurate, simple and non-destructive estimation of LA across apricot cultivars without the use of any expensive device

    Parameters for irreversible inactivation of monoamine oxidase

    Get PDF
    Funding:RRR, AA, SH and SB are grateful to COST Action CA13153 for facilitating their collaboration and funding short-term visits. AA acknowledges funding under P1-0005 (Slovenian Research Agency). The APC was funded by MDPI.The irreversible inhibitors of monoamine oxidases (MAO) slow neurotransmitter metabolism in depression and neurodegenerative diseases. After oxidation by MAO, hydrazines, cyclopropylamines and propargylamines form a covalent adduct with the flavin cofactor. To assist the design of new compounds to combat neurodegeneration, we have updated the kinetic parameters defining the interaction of these established drugs with human MAO-A and MAO-B and analyzed the required features. The Ki values for binding to MAO-A and molecular models show that selectivity is determined by the initial reversible binding. Common to all the irreversible inhibitor classes, the non-covalent 3D-chemical interactions depend on a H-bond donor and hydrophobic-aromatic features within 5.7 angstroms apart and an ionizable amine. Increasing hydrophobic interactions with the aromatic cage through aryl halogenation is important for stabilizing ligands in the binding site for transformation. Good and poor inactivators were investigated using visible spectroscopy and molecular dynamics. The initial binding, close and correctly oriented to the FAD, is important for the oxidation, specifically at the carbon adjacent to the propargyl group. The molecular dynamics study also provides evidence that retention of the allenyl imine product oriented towards FADH− influences the formation of the covalent adduct essential for effective inactivation of MAO.Publisher PDFPeer reviewe

    Integration between ground based and satellite SAR data in landslide mapping: The San Fratello case study

    Get PDF
    AbstractThe potential use of the integration of PSI (Persistent Scatterer Interferometry) and GB-InSAR (Ground-based Synthetic Aperture Radar Interferometry) for landslide hazard mitigation was evaluated for mapping and monitoring activities of the San Fratello landslide (Sicily, Italy). Intense and exceptional rainfall events are the main factors that triggered several slope movements in the study area, which is susceptible to landslides, because of its steep slopes and silty–clayey sedimentary cover.In the last three centuries, the town of San Fratello was affected by three large landslides, developed in different periods: the oldest one occurred in 1754, damaging the northeastern sector of the town; in 1922 a large landslide completely destroyed a wide area in the western hillside of the town. In this paper, the attention is focussed on the most recent landslide that occurred on 14 February 2010: in this case, the phenomenon produced the failure of a large sector of the eastern hillside, causing severe damages to buildings and infrastructures. In particular, several slow-moving rotational and translational slides occurred in the area, making it suitable to monitor ground instability through different InSAR techniques.PS-InSAR™ (permanent scatterers SAR interferometry) techniques, using ERS-1/ERS-2, ENVISAT, RADARSAT-1, and COSMO-SkyMed SAR images, were applied to analyze ground displacements during pre- and post-event phases. Moreover, during the post-event phase in March 2010, a GB-InSAR system, able to acquire data continuously every 14min, was installed collecting ground displacement maps for a period of about three years, until March 2013. Through the integration of space-borne and ground-based data sets, ground deformation velocity maps were obtained, providing a more accurate delimitation of the February 2010 landslide boundary, with respect to the carried out traditional geomorphological field survey. The integration of GB-InSAR and PSI techniques proved to be very effective in landslide mapping in the San Fratello test site, representing a valid scientific support for local authorities and decision makers during the post-emergency management

    Biodegradable mulching spray for weed control in the cultivation of containerized ornamental shrubs

    Get PDF
    Abstract Background Weed control represents a major issue in plant cultivation in containers. Manual weed control is very expensive and the use of chemical herbicide or plastic mulch films has a large environmental impact. The aim of this study was to test the efficacy of an experimental biodegradable chitosan-based mulching spray in controlling weed growth in containers. This research also studied the effect of this mulch on the growth of Viburnum lucidum Mill. plants to test for possible phytotoxic effects. Results The study compared a total of six treatments derived from three types of weed control (no weed control; herbicide, oxadiazon; mulching spray) applied in containers either filled only with the sterile substrate or filled with the sterile substrate and then artificially inoculated with seeds of the weed species [Sonchus asper (L.) Hill subsp. asper and Epilobium montanum L.]. The mulch controlled the weeds effectively for more than 2 months after its application even under severe weed infestation. The mulching spray controlled the emergence of S. asper more efficiently than E. montanum plants, probably because the latter has a stronger capacity to penetrate the mulch film during emergence. Conclusions Three months after its application, the mulch started to degrade and this allowed some weeds to emerge in the containers, but, in general, the mulch performed better than the herbicide. The chitosan-based mulch did not have any negative effective on the growth of V. lucidum plants

    Management of pheochromocytoma during pregnancy from diagnosis to laparoscopic adrenalectomy. A case report and review of literature

    Get PDF
    INTRODUCTION: Pheochromocytoma is an endocrine tumour of chromaffin cells. It can be diagnosed either sporadically or in the context of hereditary syndromes (e.g. Von Hippel Lindau, Neurofibromatosis type 1 and multiple neuroendocrine neoplasia type 2). During pregnancy, its frequency is very low (about 0,007%). This tumour causes paroxysmal hypertension in 0,1-0,6% pregnant women, because of an overproduction of catecholamines. If undiagnosed and nontreated, it's associated with high maternal and fetal mortality (40-50%). We report the case of a 30-year-old female diagnosed with pheochromocytoma during pregnancy at week 31 of gestation. In a multidisciplinary team made of surgeons, gynaecologists, anaesthetists, geneticists and endocrinologists we evaluated the case and according to literature, we choose a surgical approach after childbirth: performing a laparoscopic right adrenalectomy. DISCUSSION: In pregnancy, pheochromocytoma is a rare clinical condition. Gold standard treatment is laparoscopic adrenalectomy. However, the optimum timing of surgery is a challenge. CONCLUSION: Timely diagnosis of pheochromocytoma in pregnant women with hypertension and appropriate therapeutic management can lead to improve maternal, fetal and neonatal outcomes. The multidisciplinary team is necessary to recognize the symptoms and to adopt the right pre - and post - operative treatment. Laparoscopic adrenalectomy after delivery is safe and feasible even though the surgical procedure should be performed by an experienced surgeon. KEY WORDS: Pheochromocytoma, Pregnancy, Laparoscopic adrenalectomy and pregnancy, Management of pheochromocytoma, Laparoscopic adrenalectomy, Adrenalectomy, Pregnancy and pheochromocytoma

    Effects of mitotane on the hypothalamic-pituitary-adrenal axis in patients with adrenocortical carcinoma

    Get PDF
    Objective: Mitotane, a drug used to treat adrenocortical cancer (ACC), inhibits multiple enzymatic steps of adrenocortical steroid biosynthesis, potentially causing adrenal insufficiency. Recent studies in vitro have also documented a direct inhibitory effect of mitotane at the pituitary level. The present study was aimed to assess the hypothalamic-pituitary-adrenal axis in patients with ACC receiving mitotane. Design and methods: We prospectively enrolled 16 patients on adjuvant treatment with mitotane after radical surgical resection of ACC, who underwent standard hormone evaluation and h-CRH stimulation. A group of 10 patients with primary adrenal insufficiency (PAI) served as controls for the CRH test. Results: We demonstrated a close correlation between cortisol-binding globulin (CBG) and plasma mitotane levels, and a non-significant trend between mitotane dose and either serum or salivary cortisol in ACC patients. We did not find any correlation between the dose of cortisone acetate and either ACTH or cortisol levels. ACTH levels were significantly higher in patients with PAI than that in patients with ACC, both in baseline conditions (88.99 (11.04-275.00) vs 24.53 (6.16-121.88) pmol/L, P = 0.031) and following CRH (158.40 (34.32-275.00) vs 67.43 (8.8-179.52) pmol/L P = 0.016). Conclusions: The observation of lower ACTH levels in patients with ACC than that in patients with PAI, both in basal conditions and after CRH stimulation, suggests that mitotane may play an inhibitory effect on ACTH secretion at the pituitary levels. In conclusion, the present study shows that mitotane affects the HPA axis at multiple levels and no single biomarker may be used for the assessment of adrenal insufficiency
    • …
    corecore