1,003 research outputs found
CFD prediction of scalar transport in thin channels for reverse electrodialysis
Reverse ElectroDialysis (RED) is a very promising technology allowing the electrochemical potential difference of a salinity gradient to be directly converted into electric energy. The fluid dynamics optimization of the thin channels used in RED is still an open problem. The present preliminary work focuses on the Computational Fluid Dynamics (CFD) simulation of the flow and concentration fields in these channels. In particular three different configurations were investigated: a channel unprovided with a spacer (empty channel) and two channels filled with spacers, one made of overlapped filaments the other of woven filaments. The transport of two passive scalars, representative of the ions present in the solution, was simulated in order to evaluate concentration polarization phenomena. Computational domain effects were also addressed.
Results show that: (i) the adoption of a computational domain limited to a single unit cell along with periodic boundary conditions provides results very close to those obtained in a larger domain; (ii) the woven spacer filled channel is the best compromise between pressure drop and concentration polarization.
Future work will address the inclusion of electrical effects along with the migrative transport of the ions in the channel
CFD PREDICTION OF SCALAR TRANPORT IN THIN CHANNELS FOR REVERSE ELECTRODIALYSIS
Reverse ElectroDialysis (RED) is a very promising technology allowing the electrochemical potential difference of a salinity gradient to be directly converted into electric energy.
Fluid dynamics optimization of the thin channels to be devoted for the RED process is still an open problem. The present preliminary work focuses on the Computational Fluid Dynamics (CFD) simulation of the flow and concentration fields in these channels. In particular three different configurations were investigated: a channel unprovided with a spacer and two different spacer (made
of either overlapped filaments or woven filaments) filled channels. Two passive scalars were transported along with the water in order to evaluate concentration polarization phenomena. Grid topology and computational domain effects were also addressed.
Results show that: (i) the grid topology affects the concentration boundary layer; (ii) the adoption of a small computational domain along with periodic boundary conditions provide the same flow field obtained with a wider domain; (iii) the woven spacer filled channel is the best compromise between pressure drops and concentration polarization.
Future works will address the inclusion of electrical effects along with the migrative transport of the ions in the channel
Non-Invasive Detection of a De Novo Frameshift Variant of STAG2 in a Female Fetus: Escape Genes Influence the Manifestation of X-Linked Diseases in Females
Background: We report on a 20-week-old female fetus with a diaphragmatic hernia and other malformations, all of which appeared after the first-trimester ultrasound. Methods and Results: Whole trio exome sequencing (WES) on cell-free fetal DNA (cff-DNA) revealed a de novo frameshift variant of the X-linked STAG2 gene. Loss-of-function (LoF) STAG2 variants cause either holoprosencephaly (HPE) or Mullegama–Klein–Martinez syndrome (MKMS), are de novo, and only affect
females, indicating male lethality. In contrast, missense mutations associate with milder forms of MKMS and follow the classic X-linked recessive inheritance transmitted from healthy mothers to male offspring. STAG2 has been reported to escape X-inactivation, suggesting that disease onset in LoF females is dependent on inadequate dosing for at least some of the transcripts, as is the case with a part of the autosomal dominant diseases. Missense STAG2 variants produce a quantity
of transcripts, which, while resulting in a different protein, leads to disease only in hemizygous males. Similar inheritance patterns are described for other escapee genes. Conclusions: This study confirms the advantage of WES on cff-DNA and emphasizes the role of the type of the variant in X-linked disorders
Variable clinical expression of Stickler Syndrome: A case report of a novel COL11A1 mutation
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The thin and medium filters of the EPIC camera on-board XMM-Newton: measured performance after more than 15 years of operation
After more than 15 years of operation of the EPIC camera on board the XMM-Newton X-ray observatory, we have reviewed the status of its Thin and Medium filters. We have selected a set of Thin and Medium back-up filters among those still available in the EPIC consortium and have started a program to investigate their status by different laboratory measurements including: UV/VIS transmission, Raman scattering, X-Ray Photoelectron Spectroscopy, and Atomic Force Microscopy. Furthermore, we have investigated the status of the EPIC flight filters by performing an analysis of the optical loading in the PN offset maps to gauge variations in the optical and UV transmission. We both investigated repeated observations of single optically bright targets and performed a statistical analysis of the extent of loading versus visual magnitude at different epochs. We report the results of the measurements conducted up to now. Most notably, we find no evidence for change in the UV/VIS transmission of the back-up filters in ground tests spanning a 2 year period and we find no evidence for change in the optical transmission of the thin filter of the EPIC-pn camera from 2002 to 2012. We point out some lessons learned for the development and calibration programs of filters for X-ray detectors in future Astronomy missions
The role of attitudes toward medication and treatment adherence in the clinical response to LAIs: findings from the STAR Network Depot Study
Background: Long-acting injectable (LAI) antipsychotics are efficacious in managing psychotic symptoms in people affected by severe mental disorders, such as schizophrenia and bipolar disorder. The present study aimed to investigate whether attitude toward treatment and treatment adherence represent predictors of symptoms changes over time. Methods: The STAR Network "Depot Study" was a naturalistic, multicenter, observational, prospective study that enrolled people initiating a LAI without restrictions on diagnosis, clinical severity or setting. Participants from 32 Italian centers were assessed at three time points: baseline, 6-month, and 12-month follow-up. Psychopathological symptoms, attitude toward medication and treatment adherence were measured using the Brief Psychiatric Rating Scale (BPRS), the Drug Attitude Inventory (DAI-10) and the Kemp's 7-point scale, respectively. Linear mixed-effects models were used to evaluate whether attitude toward medication and treatment adherence independently predicted symptoms changes over time. Analyses were conducted on the overall sample and then stratified according to the baseline severity (BPRS < 41 or BPRS ≥ 41). Results: We included 461 participants of which 276 were males. The majority of participants had received a primary diagnosis of a schizophrenia spectrum disorder (71.80%) and initiated a treatment with a second-generation LAI (69.63%). BPRS, DAI-10, and Kemp's scale scores improved over time. Six linear regressions-conducted considering the outcome and predictors at baseline, 6-month, and 12-month follow-up independently-showed that both DAI-10 and Kemp's scale negatively associated with BPRS scores at the three considered time points. Linear mixed-effects models conducted on the overall sample did not show any significant association between attitude toward medication or treatment adherence and changes in psychiatric symptoms over time. However, after stratification according to baseline severity, we found that both DAI-10 and Kemp's scale negatively predicted changes in BPRS scores at 12-month follow-up regardless of baseline severity. The association at 6-month follow-up was confirmed only in the group with moderate or severe symptoms at baseline. Conclusion: Our findings corroborate the importance of improving the quality of relationship between clinicians and patients. Shared decision making and thorough discussions about benefits and side effects may improve the outcome in patients with severe mental disorders
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
Treatment persistence with aripiprazole once monthly: a 4-year follow-up
Objectives: Treatment persistence refers to the act of continuing a treatment as prescribed and reflects the patient's or doctor's judgment about efficacy, tolerability, and acceptability. In patients with schizophrenia, antipsychotic persistence is often poor, because of issues such as lack or loss of efficacy, side effects, and poor adherence, which is often related to the degree to which patients find the medication and overall intervention to be helpful, tolerable, fair, reasonable, appropriate, and consistent with expectations of treatment. Despite the poor antipsychotic persistence that has been reported to date in patients with schizophrenia, we previously observed a relatively high (86%) 6 months persistence with aripiprazole once-monthly (AOM) in a group of patients with schizophrenia, treated in the real world Italian clinical practice. The present study explores the longer term persistence with AOM, over a mean follow-up period of 48 months. Methods: This was a multicenter, retrospective, non-interventional follow-up study, aimed at evaluating the longer term persistence with AOM in a group of patients with schizophrenia who had already shown persistence over a period of at least 6 months. The study included 161 individuals who had participated in our previous study, where 86% of participating individuals had shown persistence with AOM for at least 6 months. Non-persistence was defined as discontinuing the medication for any reason. Baseline demographic and clinical characteristics of patients who continued AOM were then compared to those of patients who discontinued the medication. Results: Study subjects were predominantly male (64.4%) and their mean age was 39.7 (SD: 12.24). Treatment persistence with AOM was 69.6% and 112 out of 161 patients were still receiving AOM treatment at the last follow-up visit. The mean duration of AOM treatment until the last recorded observation was 55.87 months (median 56.17, SD6.23) for the 112 persistent patients and 32.23 (median 28.68.SD 15.09) months for the 49 non-persistent individuals. The mean observation period for all patients (persistent and non-persistent) was 48.78 months (median 52.54, SD 14.64). For non-persistent subjects, the observation period ended with the discontinuation of AOM. Subjects treated with AOM at 400 mg presented a 69.6% lower risk of all-cause treatment discontinuation when compared with patients treated with 300 mg (HR: 0.314; 95% confidence interval [CI] 0.162-0.608; P = 0.001). The main reasons for discontinuation were lack of efficacy (30.6%), patient/caregiver choice (18.4%), physician's choice (16.3%), non-adherence (12.2%) and inconvenience (6.1%). Only 3 patients (6.1%) discontinued AOM for tolerability issues. Conclusions: In subjects with schizophrenia, who had already shown a 6 months persistence with AOM, a high number of patients (69.6%) continued to be persistent over a 4-year follow-up period. This may reflect a favourable profile of efficacy, tolerability, and acceptability. Larger and prospective studies are warranted to confirm our observations
Effect of annealing on structure and superconducting properties in Fe(Se,Te)
Abstract
In this paper, the effect of post synthesis annealing treatments on a Fe(Se,Te) polycrystalline material is evaluated and discussed. The samples have been obtained via melting route. The material has been subjected to a high-temperature annealing treatment, carried out for 45 h at 680 °C. The role of the cooling step was investigated comparing samples obtained after a controlled cooling or after quenching in liquid nitrogen. From a morpho-structural point of view, the annealing treatment improves homogeneity, with respect to pristine samples, and influences secondary phase precipitate morphology. Regarding superconducting properties, a key role of the cooling procedure is assessed: controlled cooling leads in fact to a significant improvement of high field behaviour with respect to the melted material, while quenched samples are characterized by a worsening of the superconducting properties. Despite the overall worsening, however, the quenched samples show evidence of the presence of superconducting phases characterized by a remarkably high critical temperature (Tc
> 18 K), observed for these materials only in films or under pressure
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