96 research outputs found
Study of strain localizations in a polycrystalline medium in presence of a quasi-static crack
Numerical techniques have been widely applied in many recent works to investigate micro-scale behavior of materials. This work focuses on the analysis of strain localizations in a Nickel-based alloy, Haynes 230. Numerical models and experiments concern the study of the strain field generated around the crack tip inside a polycrystalline medium when the crack is quasi-static (not propagating). Experimentally, the tests were conducted in load control; one face of the specimens was monitored by high-resolution Digital Image Correlation (DIC) technique to evaluate the strain field ahead of the crack tip. The simulations were conducted adopting an open source finite element code, Warp3D, which implements a state of art Crystal Plasticity (CP) model. The models of the polycrystalline matrix were created considering the data obtained inspecting the specimen surface by the Electron Back-Scatter Diffraction (EBSD) technique, which allowed defining grains size and orientations. Experimental and numerical results were then compared in terms of strain localizations to evaluate the prediction capabilities of the models. The comparison focused on strain field extension and active grains
Efficacy of atropine 0.01% for the treatment of childhood myopia in European patients
Purpose: To evaluate the efficacy and safety of atropine 0.01% in slowing myopia progression in European paediatric patients. Methods: Retrospective, medical records review study. Medical charts of paediatric patients with a myopia progression > 0.5 D/year treated with atropine 0.01% for at least 1 year were included. Patients receive a complete ophthalmic examination before and 12 months after initiation of atropine treatment. A group of myopic untreated children serves as a control group. The rate of myopia progression at baseline and 12 months after treatment with atropine was evaluated. The rate of myopia progression in treated and untreated patients was also compared. Adverse events were recorded. Results: Medical records of 52 treated and 50 control subjects were analysed. In the atropine group, the mean rate of myopia progression after 12 months of treatment ( 120.54 \ub1 0.61 D) was significantly slower compared with the baseline progression ( 121.20 \ub1 0.64 D; p < 0.0001) and to the progression in the control group ( 121.09 \ub1 0.64; p < 0.0001). The responders patients were 41/52 (79%), whereas 11/52 patients (21%) showed a progression > 0.50 D despite treatment. The only adverse event was temporary photophobia in five patients (9.6%), severe adverse events were not reported, and none of the patients discontinued the treatment. Conclusion: Low-dose atropine significantly slowed the rate of myopia progression in European paediatric patients with a favourable safety profile
Dry eye in vernal keratoconjunctivitis
The purpose of this comparative cross-sectional study was to investigate the use of standardized clinical tests for dry eye in pediatric patients with active and quiet vernal keratoconjunctivitis (VKC) and to compare them with healthy children. We recruited 35 active VKC, 35 inactive VKC, and 70 age-matched control healthy subjects. Each child underwent a complete eye examination, including visual analog scale symptoms assessment, biomicroscopy, fluorescein break-up time (BUT), corneal fluorescein and conjunctival lissamine green staining, corneal esthesiometry, Schirmer test with anesthetic, and meibomian glands inspection and expression. Active VKC patients showed significantly increased symptoms and signs of ocular surface disease, compared with the other 2 groups. Inactive VKC patients, compared with control subjects, showed increased photophobia (P<0.05; Mann-Whitney U test), conjunctival lissamine green staining and Schirmer test values, and reduced BUT and corneal sensitivity [P<0.05 by analysis of variance (ANOVA) least significant difference posthoc test for BUT and Schirmer; P<0.001 by Mann-Whitney U test for lissamine green staining and corneal sensitivity]. Our results confirm the association between VKC and short-BUT dry eye. This syndrome seems to affect the ocular surface in quiescent phases too, determining abnormalities in tear film stability, epithelial cells integrity, and corneal nerves function. The very long-term consequences of this perennial mechanism of ocular surface damage have not been fully understood yet
Towards a landscape ecosophy. Interpreting how the Villarrica-Pucón urban system inhabitants in the AraucanÃa region of Chile perceive and relate with the dynamics of Landscape
The PROVENT-C19 registry: A study protocol for international multicenter SIAARTI registry on the use of prone positioning in mechanically ventilated patients with COVID-19 ARDS
Background The worldwide use of prone position (PP) for invasively ventilated patients with COVID-19 is progressively increasing from the first pandemic wave in everyday clinical practice. Among the suggested treatments for the management of ARDS patients, PP was recommended in the Surviving Sepsis Campaign COVID-19 guidelines as an adjuvant therapy for improving ventilation. In patients with severe classical ARDS, some authors reported that early application of prolonged PP sessions significantly decreases 28-day and 90-day mortality. Methods and analysis Since January 2021, the COVID19 Veneto ICU Network research group has developed and implemented nationally and internationally the "PROVENT-C19 Registry", endorsed by the Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care. . .'(SIAARTI). The PROVENT-C19 Registry wishes to describe 1. The real clinical practice on the use of PP in COVID-19 patients during the pandemic at a National and International level; and 2. Potential baseline and clinical characteristics that identify subpopulations of invasively ventilated patients with COVID-19 that may improve daily from PP therapy. This web-based registry will provide relevant information on how the database research tools may improve our daily clinical practice. Conclusions This multicenter, prospective registry is the first to identify and characterize the role of PP on clinical outcome in COVID-19 patients. In recent years, data emerging from large registries have been increasingly used to provide real-world evidence on the effectiveness, quality, and safety of a clinical intervention. Indeed observation-based registries could be effective tools aimed at identifying specific clusters of patients within a large study population with widely heterogeneous clinical characteristics. Copyright
Off–label long acting injectable antipsychotics in real–world clinical practice: a cross-sectional analysis of prescriptive patterns from the STAR Network DEPOT study
Introduction: Information on the off–label use of Long–Acting Injectable (LAI) antipsychotics in the real world is lacking. In this study, we aimed to identify the sociodemographic and clinical features of patients treated with on– vs off–label LAIs and predictors of off–label First– or Second–Generation Antipsychotic (FGA vs. SGA) LAI choice in everyday clinical practice. Method: In a naturalistic national cohort of 449 patients who initiated LAI treatment in the STAR Network Depot Study, two groups were identified based on off– or on–label prescriptions. A multivariate logistic regression analysis was used to test several clinically relevant variables and identify those associated with the choice of FGA vs SGA prescription in the off–label group. Results: SGA LAIs were more commonly prescribed in everyday practice, without significant differences in their on– and off–label use. Approximately 1 in 4 patients received an off–label prescription. In the off–label group, the most frequent diagnoses were bipolar disorder (67.5%) or any personality disorder (23.7%). FGA vs SGA LAI choice was significantly associated with BPRS thought disorder (OR = 1.22, CI95% 1.04 to 1.43, p = 0.015) and hostility/suspiciousness (OR = 0.83, CI95% 0.71 to 0.97, p = 0.017) dimensions. The likelihood of receiving an SGA LAI grew steadily with the increase of the BPRS thought disturbance score. Conversely, a preference towards prescribing an FGA was observed with higher scores at the BPRS hostility/suspiciousness subscale. Conclusion: Our study is the first to identify predictors of FGA vs SGA choice in patients treated with off–label LAI antipsychotics. Demographic characteristics, i.e. age, sex, and substance/alcohol use co–morbidities did not appear to influence the choice towards FGAs or SGAs. Despite a lack of evidence, clinicians tend to favour FGA over SGA LAIs in bipolar or personality disorder patients with relevant hostility. Further research is needed to evaluate treatment adherence and clinical effectiveness of these prescriptive patterns
Comparing Long-Acting Antipsychotic Discontinuation Rates Under Ordinary Clinical Circumstances: A Survival Analysis from an Observational, Pragmatic Study
Background: Recent guidelines suggested a wider use of long-acting injectable antipsychotics (LAI) than previously, but naturalistic data on the consequences of LAI use in terms of discontinuation rates and associated factors are still sparse, making it hard for clinicians to be informed on plausible treatment courses. Objective: Our objective was to assess, under real-world clinical circumstances, LAI discontinuation rates over a period of 12 months after a first prescription, reasons for discontinuation, and associated factors. Methods: The STAR Network ‘Depot Study’ was a naturalistic, multicentre, observational prospective study that enrolled subjects initiating a LAI without restrictions on diagnosis, clinical severity or setting. Participants from 32 Italian centres were assessed at baseline and at 6 and 12 months of follow-up. Psychopathology, drug attitude and treatment adherence were measured using the Brief Psychiatric Rating Scale, the Drug Attitude Inventory and the Kemp scale, respectively. Results: The study followed 394 participants for 12 months. The overall discontinuation rate at 12 months was 39.3% (95% confidence interval [CI] 34.4–44.3), with paliperidone LAI being the least discontinued LAI (33.9%; 95% CI 25.3–43.5) and olanzapine LAI the most discontinued (62.5%; 95% CI 35.4–84.8). The most frequent reason for discontinuation was onset of adverse events (32.9%; 95% CI 25.6–40.9) followed by participant refusal of the medication (20.6%; 95% CI 14.6–27.9). Medication adherence at baseline was negatively associated with discontinuation risk (hazard ratio [HR] 0.853; 95% CI 0.742–0.981; p = 0.026), whereas being prescribed olanzapine LAI was associated with increased discontinuation risk compared with being prescribed paliperidone LAI (HR 2.156; 95% CI 1.003–4.634; p = 0.049). Conclusions: Clinicians should be aware that LAI discontinuation is a frequent occurrence. LAI choice should be carefully discussed with the patient, taking into account individual characteristics and possible obstacles related to the practicalities of each formulation
Primary cerebellar glioblastoma multiforme
Glioblastoma multiforme in adults arising in the cerebellum is a rare tumor, well documented in only 13 cases in the literature. We report a fourteenth case, an 80-year-old female, and reassess the clinical and CT aspects of this tumor based on a review of the world's literature. The median age of patients is 53 years with a median survival of three months, which is less than adult cerebral hemisphere malignant gliomas.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45390/1/11060_2004_Article_BF00151226.pd
Strategies to Calculate Water Binding Free Energies in Protein–Ligand Complexes
Water molecules are commonplace in protein binding pockets, where they can typically form a complex between the protein and a ligand or become displaced upon ligand binding. As a result, it is often of great interest to establish both the binding free energy and location of such molecules. Several approaches to predicting the location and affinity of water molecules to proteins have been proposed and utilized in the literature, although it is often unclear which method should be used under what circumstances. We report here a comparison between three such methodologies, Just Add Water Molecules (JAWS), Grand Canonical Monte Carlo (GCMC), and double-decoupling, in the hope of understanding the advantages and limitations of each method when applied to enclosed binding sites. As a result, we have adapted the JAWS scoring procedure, allowing the binding free energies of strongly bound water molecules to be calculated to a high degree of accuracy, requiring significantly less computational effort than more rigorous approaches. The combination of JAWS and GCMC offers a route to a rapid scheme capable of both locating and scoring water molecules for rational drug design
Crack-closure simulations of Ni-based super-alloy polycrystal, a comparison between experiments and crystal plasticity
Fatigue crack growth in polycrystalline specimens was investigated considering a Ni-based superalloy, Haynes 230. The analyses were carried out through a comparison between experiments and numerical simulations. Crack closure experiments were conducted with digital image correlations: the crack closure was estimated by measuring the relative displacements of crack flanks. The experimental results were compared with crystal plasticity finite element simulations of randomly generated polycrystalline structures, in which the crack growth was simulated through a node release technique. The simulations provided a good estimation of the experimental results in terms of crack opening levels for different loading conditions
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