252 research outputs found

    From the Equations of Motion to the Canonical Commutation Relations

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    The problem of whether or not the equations of motion of a quantum system determine the commutation relations was posed by E.P.Wigner in 1950. A similar problem (known as "The Inverse Problem in the Calculus of Variations") was posed in a classical setting as back as in 1887 by H.Helmoltz and has received great attention also in recent times. The aim of this paper is to discuss how these two apparently unrelated problems can actually be discussed in a somewhat unified framework. After reviewing briefly the Inverse Problem and the existence of alternative structures for classical systems, we discuss the geometric structures that are intrinsically present in Quantum Mechanics, starting from finite-level systems and then moving to a more general setting by using the Weyl-Wigner approach, showing how this approach can accomodate in an almost natural way the existence of alternative structures in Quantum Mechanics as well.Comment: 199 pages; to be published in "La Rivista del Nuovo Cimento" (www.sif.it/SIF/en/portal/journals

    Hydrodynamic Models with Quantum Corrections

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    We derive a quantum-corrected hydrodynamic and drift-diffusion model for the out-of-equilibrium particle dynamics in the presence of particle collisions, modeled by a BGK collision term. The quantum mechanical corrections are obtained within the Liouville formalism and are expressed by an effective nonlinear force. The Boltzmann and Fermi-Dirac statistics are included

    NemaFootPrinter: a web based software for the identification of conserved non-coding genome sequence regions between C. elegans and C. briggsae

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    BACKGROUND: NemaFootPrinter (Nematode Transcription Factor Scan Through Philogenetic Footprinting) is a web-based software for interactive identification of conserved, non-exonic DNA segments in the genomes of C. elegans and C. briggsae. It has been implemented according to the following project specifications: a) Automated identification of orthologous gene pairs. b) Interactive selection of the boundaries of the genes to be compared. c) Pairwise sequence comparison with a range of different methods. d) Identification of putative transcription factor binding sites on conserved, non-exonic DNA segments. RESULTS: Starting from a C. elegans or C. briggsae gene name or identifier, the software identifies the putative ortholog (if any), based on information derived from public nematode genome annotation databases. The investigator can then retrieve the genome DNA sequences of the two orthologous genes; visualize graphically the genes' intron/exon structure and the surrounding DNA regions; select, through an interactive graphical user interface, subsequences of the two gene regions. Using a bioinformatics toolbox (Blast2seq, Dotmatcher, Ssearch and connection to the rVista database) the investigator is able at the end of the procedure to identify and analyze significant sequences similarities, detecting the presence of transcription factor binding sites corresponding to the conserved segments. The software automatically masks exons. DISCUSSION: This software is intended as a practical and intuitive tool for the researchers interested in the identification of non-exonic conserved sequence segments between C. elegans and C. briggsae. These sequences may contain regulatory transcriptional elements since they are conserved between two related, but rapidly evolving genomes. This software also highlights the power of genome annotation databases when they are conceived as an open resource and the possibilities offered by seamless integration of different web services via the http protocol. Availability: the program is freely available a

    Impact of supplementation with vitamins B6, B12, and/or folic acid on the reduction of homocysteine levels in patients with mild cognitive impairment: A systematic review

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    Àcid fòlic; Hhomocisteïna; Deteriorament cognitiu lleuÁcido fólico; Homocisteína; Deterioro cognitivo leveFolic acid; Homocysteine; Mild cognitive impairmentHyperhomocysteinemia is an independent predictor of the risk for cognitive decline and may be a result of low levels of vitamins B12, B6, and folate. Previous findings suggest that adequate intake of these vitamins may reduce homocysteine levels. This review aimed to assess the effects of treatment with vitamins B6, B12, and/or folic acid in the homocysteine levels in patients with mild cognitive impairment (MCI). A systematic literature review was conducted in EMBASE, MEDLINE®, PsycINFO, and Cochrane Central Register of Controlled Trials. The research question was formulated using the Population, Intervention, Comparison, and Outcome (PICO) framework: in patients with MCI (P); what is the efficacy of vitamins B6, B12, and/or folic acid intake (I); compared with baseline values, and/or compared with controls (C); in reducing homocysteine levels from baseline (O). A total of eight primary studies with a total of 1,140 participants were included in the review. Four were randomized controlled trials, one was a quasi-controlled trial, and three were observational studies. All studies included folic acid in their intervention, seven vitamin B12, and four vitamin B6. Mean (SD) length of the intervention period was 18.8 (19.3) months, ranging from 1 to 60 months. All studies showed a statistically significant decrease in homocysteine levels in groups treated with vitamins B6, B12, and/or folic acid compared to controls, with a mean decline of homocysteine concentration of 31.9% in the intervention arms whereas it increased by 0.7% in the control arm. This review identified evidence of a reduction of plasma homocysteine levels in MCI patients taking vitamins B6, B12, and/or folic acid supplements, with statistically significant declines being observed after 1 month of supplementation. Findings support that supplementation with these vitamins might be an option to reduce homocysteine levels in people with MCI and elevated plasma homocysteine.Nestlé Health Science, Switzerlan

    Innovative Non-Pharmacological Management of Delirium in Persons with Dementia: New Frontiers for Physiotherapy and Occupational Therapy?

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    Delirium; Dementia; Occupational therapyDelirio; Demencia; Terapia ocupacionalDeliri; Demència; Teràpia ocupacionalBackground: Delirium and dementia are two of the most common geriatric syndromes, which requires innovative rehabilitation approaches. Aim: We aimed at determining which occupational therapy and physiotherapy interventions are applied with older people with delirium and dementia in different care settings. We also identified the assessment tools that were used. Materials and methods: We conducted a literature search for scientific articles published from 2012 to 2022 (PubMed, MEDLINE, AMED and CINAHL) with adults aged >65 years including experimental study designs with randomized or non-randomized intervention, exploratory studies, pilot studies, quasi-experimental studies, case series and/or clinical cases. Studies that did not use interventions that could be classified as occupational therapy or physiotherapy were excluded. Results: After applying the exclusion criteria, 9 articles were selected. The most widely used assessment to define dementia was the MMSE (N = 5; 55.5%), whereas the CAM (N = 2; 22.2%), CAM-ICU (N = 2; 22.2%) and RASS (N = 3; 33.3%) were the most widely used to define delirium. The rehabilitation interventions that were most frequently performed were early mobilization, inclusion of the caregiver during treatment, modification of the environment to encourage orientation and autonomy, the interprofessional systemic approach and engaging persons in meaningful activities. Conclusions: Despite the growing evidence on its effectiveness, the role of physiotherapy and occupational therapy interventions in the prevention and treatment of people with dementia and delirium is still emerging. More research is needed to investigate if effective occupational therapy programs known to reduce the behavioral and psychological symptoms in people with dementia are also useful for treating delirium and specifically delirium superimposed on dementia. Regarding physiotherapy, it is crucial to know about the amount and timing of intervention required. Further studies are needed including older adults with delirium superimposed on dementia to define the role of the interprofessional geriatric rehabilitation team

    The p75NTR-induced Apoptotic Program Develops through a Ceramide-Caspase Pathway Negatively Regulated by Nitric Oxide

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    SK-N-BE neuroblastoma cell clones transfected with p75(NTR) and lacking Trk neurotrophin receptors, previously reported to undergo extensive spontaneous apoptosis and to be protected by nerve growth factor (NGF) (Bunone, G., Mariotti, A., Compagni, A., Morandi, E., and Della Valle, G. (1997) Oncogene 14, 1463-1470), are shown to exhibit (i) increased levels of the pro-apoptotic lipid metabolite ceramide and (ii) high activity of caspases, the proteases of the cell death cascade. In the p75(NTR)-expressing cells, these parameters were partially normalized by prolonged NGF treatment, which, in addition, decreased apoptosis, similar to caspase blockers. Conversely, exogenous ceramide increased caspase activity and apoptosis in both wild-type and p75(NTR)-expressing cells. A new p75(NTR)-expressing clone characterized by low spontaneous apoptosis exhibited high endogenous ceramide and low caspase levels. A marked difference between the apoptotic and resistant clones concerned the very low and high activities of nitric-oxide (NO) synthase, respectively. Protection from apoptosis by NO was confirmed by results with the NO donor S-nitrosoacetylpenicillamine and the NO-trapping agent hemoglobin. We conclude that the p75(NTR) receptor, while free of NGF, triggers a cascade leading to apoptosis; the cascade includes generation of ceramide and increased caspase activity; and the protective role of NO occurs at step(s) in between the latter events

    Dexamethasone Prophylaxis in Pediatric Open Heart Surgery Is Associated with Increased Blood Long Pentraxin PTX3: Potential Clinical Implications

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    Glucocorticoid administration before cardiopulmonary bypass (CPB) can reduce the systemic inflammatory response and improve clinical outcome. Long pentraxin PTX3 is a novel inflammatory parameter that could play a protective cardiovascular role by regulating inflammation. Twenty-nine children undergoing open heart surgery were enrolled in the study. Fourteen received dexamethasone (1st dose 1.5 mg/Kg i.v. or i.m. the evening before surgery; 2nd dose 1.5 mg/kg i.v. before starting bypass) and fifteen children served as control. Blood PTX3, short pentraxin C-reactive protein (CRP), interleukin-1 receptor II (IL-1RII), fibrinogen and partial thromboplastin time (PTT) were assayed at different times. PTX3 levels significantly increased during CPB in dexamethasone-treated (+D) and dexamethasone-untreated (−D) subjects, but were significantly higher in +D than −D patients. CRP levels significantly increased both in +D and −D patients in the postoperative days, with values significantly higher in −D than +D patients. Fibrinogen and PTT values were significantly higher in −D than +D patients in the 1st postoperative day. IL-1RII plasma levels increased in the postoperative period in both groups. Dexamethasone prophylaxis in pediatric patients undergoing CPB for cardiac surgery is associated with a significant increase of blood PTX3 that could contribute to decreasing inflammatory parameters and improving patient clinical outcome

    13-gene DNA Methylation Analysis from Oral Brushing: A Promising Non Invasive Tool in the Follow-up of Oral Cancer Patients

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    BACKGROUND: This study aimed to evaluate the prognostic value of a non-invasive sampling procedure based on 13-gene DNA methylation analysis in the follow-up of patients previously treated for oral squamous cell carcinoma (OSCC). METHODS: The study population included 49 consecutive patients treated for OSCC. Oral brushing sample collection was performed at two different times: before any cancer treatment in the tumor mass and during patient follow-up almost 6 months after OSCC treatment, within the regenerative area after OSCC resection. Each sample was considered positive or negative in relation to a predefined cut-off value. RESULTS: Before any cancer treatment, 47/49 specimens exceeded the score and were considered as positive. Six months after OSCC resection, 16/49 specimens also had positive scores in the samples collected from the regenerative area. During the follow-up period, 7/49 patients developed locoregional relapse: 6/7 patients had a positive score in the regenerative area after OSCC resection. The presence of a positive score after oral cancer treatment was the most powerful variable related to the appearance of locoregional relapse. CONCLUSION: 13-gene DNA methylation analysis by oral brushing may have a clinical application as a prognostic non-invasive tool in the follow-up of patients surgically treated for OSCC
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