59 research outputs found
A Systematic Analysis of the Memory term in Coarse-Grained models: the case of the Markovian Approximation
The systematic development of Coarse-Grained (CG) models via the Mori-Zwanzig
projector operator formalism requires the explicit description of several
terms, including a deterministic drift term, a dissipative memory term and a
random fluctuation term. In many applications, the memory and fluctuation terms
are related by the fluctuation-dissipation relation and are, in general, more
challenging to derive than the drift term. In this work we analyse an
approximation of the memory term and propose a rational basis for a data-driven
approach to an approximation of the memory and fluctuating terms which can be
considered included in the class of the Markovian ones.Comment: 39 pages, 2 Figure
Geological map, balanced and restored cross-sections, and 3D geological model of the Monte Fema area, Umbria-Marche Apennines (Italy)
The Mt. Fema area is located within the 1:50,000 scale Sheet 325-Visso of the CARG project, in the Umbria-Marche Apennines. Here, inherited pre-orogenic deformation and multi-layered mechanical stratigraphy affect mountain belt evolution and cause along-and across-strike changes in structural architecture. Further complexity is caused by post-orogenic extensional tectonics dissecting the fold and thrust belt. In this work, we combined classical field methodologies with digital mapping and drone surveys to produce a 1:10,000 geological map of the Mt. Fema area. The resulting map was integrated with a 10 m-cell size DEM in a 3D environment to construct four balanced cross-sections that were used to document structural style and stratigraphic variations. One section was restored to quantify the amount of deformation related to both Neogene orogenic shortening and multiple extensional phases affecting the area. Ultimately, we built a 3D geological model to investigate the subsurface geometrical arrangement of strata and faults of different generations, thus the overall structural architecture of the fold and thrust belt. According to our interpretation, the Mt. Fema thrust system is characterised by relatively limited displacement (cumulative dip separation ranging from-100 m to the north in Val di Tazza to-500 m to the south in Valnerina). Reactivation of inherited normal faults was likely precluded because of their unfavourable orientation with respect to W-dipping thrusts. Inherited basin structure and mechanical stratigraphy govern folding by buckling mechanism, which in turn controls the locus of thrust propagation. Normal faults dissect the crestal region of the Mt. Fema anticline. These structures do not show evidence of surface faulting during recent seismic sequences, although earthquake epicentres fall within the study area. Our work provides new insights into the 3D structural architecture, timing, and kinematics of a key sector of the Umbria-Marche Apennines, with implications for a better understanding of the role of structural inheritance and subsequent extensional tectonics in the evolution of fold and thrust belts
A systematic analysis of the memory term in coarse-grained models: The case of the Markovian approximation
Copyright © The Author(s), 2022. The systematic development of coarse-grained (CG) models via the Mori–Zwanzig projector operator formalism requires the explicit description of a deterministic drift term, a dissipative memory term and a random fluctuation term. The memory and fluctuating terms are related by the fluctuation–dissipation relation and are more challenging to sample and describe than the drift term due to complex dependence on space and time. This work proposes a rational basis for a Markovian data-driven approach to approximating the memory and fluctuating terms. We assumed a functional form for the memory kernel and under broad regularity hypothesis, we derived bounds for the error committed in replacing the original term with an approximation obtained by its asymptotic expansions. These error bounds depend on the characteristic time scale of the atomistic model, representing the decay of the autocorrelation function of the fluctuating force; and the characteristic time scale of the CG model, representing the decay of the autocorrelation function of the momenta of the beads. Using appropriate parameters to describe these time scales, we provide a quantitative meaning to the observation that the Markovian approximation improves as they separate. We then proceed to show how the leading-order term of such expansion can be identified with the Markovian approximation usually considered in the CG theory. We also show that, while the error of the approximation involving time can be controlled, the Markovian term usually considered in CG simulations may exhibit significant spatial variation. It follows that assuming a spatially constant memory term is an uncontrolled approximation which should be carefully checked. We complement our analysis with an application to the estimation of the memory in the CG model of a one-dimensional Lennard–Jones chain with different masses and interactions, showing that even for such a simple case, a non-negligible spatial dependence for the memory term exists.Leverhulme Trust through Early Career Fellowship ECF-2016-52
Adenosine Receptors as Neuroinflammation Modulators: Role of A1 Agonists and A2A Antagonists
The pathological condition of neuroinflammation is caused by the activation of the neuroimmune cells astrocytes and microglia. The autacoid adenosine seems to be an important neuromodulator in this condition. Its main receptors involved in the neuroinflammation modulation are A1AR and A2AAR. Evidence suggests that A1AR activation produces a neuroprotective effect and A2AARs block prevents neuroinflammation. The aim of this work is to elucidate the effects of these receptors in neuroinflammation using the partial agonist 2'-dCCPA (2-chloro-N6-cyclopentyl-2'-deoxyadenosine) (C1 KiA1AR = 550 nM, KiA2AAR = 24,800 nM, and KiA3AR = 5560 nM, α = 0.70, EC50A1AR = 832 nM) and the newly synthesized in house compound 8-chloro-9-ethyl-2-phenethoxyadenine (C2 KiA2AAR = 0.75 nM; KiA1AR = 17 nM and KiA3AR = 227 nM, IC50A2AAR = 251 nM unpublished results). The experiments were performed in in vitro and in in vivo models of neuroinflammation. Results showed that C1 was able to prevent the inflammatory effect induced by cytokine cocktail (TNF-α, IL-1β, and IFN-γ) while C2 possess both anti-inflammatory and antioxidant properties, counteracting both neuroinflammation in mixed glial cells and in an animal model of neuroinflammation. In conclusion, C2 is a potential candidate for neuroinflammation therapy
The Ramazzini Institute 13-week study on glyphosate-based herbicides at human-equivalent dose in Sprague Dawley rats: Study design and first in-life endpoints evaluation
Background: Glyphosate-based herbicides (GBHs) are the most widely used pesticides worldwide, and glyphosate is the active ingredient of such herbicides, including the formulation known as Roundup. The massive and increasing use of GBHs results in not only the global burden of occupational exposures, but also increased exposure to the general population. The current pilot study represents the first phase of a long-term investigation of GBHs that we are conducting over the next 5 years. In this paper, we present the study design, the first evaluation of in vivo parameters and the determination of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA) in urine. Methods: We exposed Sprague-Dawley (SD) rats orally via drinking water to a dose of glyphosate equivalent to the United States Acceptable Daily Intake (US ADI) of 1.75 mg/kg bw/day, defined as the chronic Reference Dose (cRfD) determined by the US EPA, starting from prenatal life, i.e. gestational day (GD) 6 of their mothers. One cohort was continuously dosed until sexual maturity (6-week cohort) and another cohort was continuously dosed until adulthood (13-week cohort). Here we present data on general toxicity and urinary concentrations of glyphosate and its major metabolite AMPA. Results: Survival, body weight, food and water consumption of the animals were not affected by the treatment with either glyphosate or Roundup. The concentration of both glyphosate and AMPA detected in the urine of SD rats treated with glyphosate were comparable to that observed in animals treated with Roundup, with an increase in relation to the duration of treatment. The majority of glyphosate was excreted unchanged. Urinary levels of the parent compound, glyphosate, were around 100-fold higher than the level of its metabolite, AMPA. Conclusions: Glyphosate concentrations in urine showed that most part of the administered dose was excreted as unchanged parent compound upon glyphosate and Roundup exposure, with an increasing pattern of glyphosate excreted in urine in relation to the duration of treatment. The adjuvants and the other substances present in Roundup did not seem to exert a major effect on the absorption and excretion of glyphosate. Our results demonstrate that urinary glyphosate is a more relevant marker of exposure than AMPA in the rodent model
Safety of fertility preservation techniques before and after anticancer treatments in young women with breast cancer: a systematic review and meta-analysis
Study question: Is it safe to perform controlled ovarian stimulation (COS) for fertility preservation before starting anticancer therapies or ART after treatments in young breast cancer patients? Summary answer: Performing COS before, or ART following anticancer treatment in young women with breast cancer does not seem to be associated with detrimental prognostic effect in terms of breast cancer recurrence, mortality or event-free survival (EFS). What is known already: COS for oocyte/embryo cryopreservation before starting chemotherapy is standard of care for young women with breast cancer wishing to preserve fertility. However, some oncologists remain concerned on the safety of COS, particularly in patients with hormone-sensitive tumors, even when associated with aromatase inhibitors. Moreover, limited evidence exists on the safety of ART in breast cancer survivors for achieving pregnancy after the completion of anticancer treatments. Study design, size, duration: The present systematic review and meta-analysis was carried out by three blinded investigators using the keywords 'breast cancer' and 'fertility preservation'; keywords were combined with Boolean operators. Eligible studies were identified by a systematic literature search of Medline, Web of Science, Embase and Cochrane library with no language or date restriction up to 30 June 2021. Participants/materials, setting, methods: To be included in this meta-analysis, eligible studies had to be case-control or cohort studies comparing survival outcomes of women who underwent COS or ART before or after breast cancer treatments compared to breast cancer patients not exposed to these strategies. Survival outcomes of interest were cancer recurrence rate, relapse rate, overall survival and number of deaths. Adjusted relative risk (RR) and hazard ratio (HR) with 95% CI were extracted. When the number of events for each group were available but the above measures were not reported, HRs were estimated using the Watkins and Bennett method. We excluded case reports or case series with <10 patients and studies without a control group of breast cancer patients who did not pursue COS or ART. Quality of data and risk of bias were assessed using the Newcastle-Ottawa Assessment Scale. Main results and the role of chance: A total of 1835 records were retrieved. After excluding ineligible publications, 15 studies were finally included in the present meta-analysis (n = 4643). Among them, 11 reported the outcomes of breast cancer patients who underwent COS for fertility preservation before starting chemotherapy, and 4 the safety of ART following anticancer treatment completion. Compared to women who did not receive fertility preservation at diagnosis (n = 2386), those who underwent COS (n = 1594) had reduced risk of recurrence (RR 0.58, 95% CI 0.46-0.73) and mortality (RR 0.54, 95% CI 0.38-0.76). No detrimental effect of COS on EFS was observed (HR 0.76, 95% CI 0.55-1.06). A similar trend of better outcomes in terms of EFS was observed in women with hormone-receptor-positive disease who underwent COS (HR 0.36, 95% CI 0.20-0.65). A reduced risk of recurrence was also observed in patients undergoing COS before neoadjuvant chemotherapy (RR 0.22, 95% CI 0.06-0.80). Compared to women not exposed to ART following completion of anticancer treatments (n = 540), those exposed to ART (n = 123) showed a tendency for better outcomes in terms of recurrence ratio (RR 0.34, 95% CI 0.17-0.70) and EFS (HR 0.43, 95% CI 0.17-1.11). Limitations, reasons for caution: This meta-analysis is based on abstracted data and most of the studies included are retrospective cohort studies. Not all studies had matching criteria between the study population and the controls, and these criteria often differed between the studies. Moreover, rate of recurrence is reported as a punctual event and it is not possible to establish when recurrences occurred and whether follow-up, which was shorter than 5 years in some of the included studies, is adequate to capture late recurrences. Wider implications of the findings: Our results demonstrate that performing COS at diagnosis or ART following treatment completion does not seem to be associated with detrimental prognostic effect in young women with breast cancer, including among patients with hormone receptor-positive disease and those receiving neoadjuvant chemotherapy. Study funding/competing interest(s): Partially supported by the Associazione Italiana per la Ricerca sul Cancro (AIRC; grant number MFAG 2020 ID 24698) and the Italian Ministry of Health-5
7 1000 funds 2017 (no grant number). M.L. acted as consultant for Roche, Pfizer, Novartis, Lilly, AstraZeneca, MSD, Exact Sciences, Gilead, Seagen and received speaker honoraria from Roche, Pfizer, Novartis, Lilly, Ipsen, Takeda, Libbs, Knight, Sandoz outside the submitted work. F.S. acted as consultant for Novartis, MSD, Sun Pharma, Philogen and Pierre Fabre and received speaker honoraria from Roche, Novartis, BMS, MSD, Merck, Sun Pharma, Sanofi and Pierre Fabre outside the submitted work. I.D. has acted as a consultant for Roche, has received research grants from Roche and Ferring, has received reagents for academic clinical trial from Roche diagnostics, speaker's fees from Novartis, and support for congresses from Theramex and Ferring outside the submitted work. L.D.M. reported honoraria from Roche, Novartis, Eli Lilly, MSD, Pfizer, Ipsen, Novartis and had an advisory role for Roche, Eli Lilly, Novartis, MSD, Genomic Health, Pierre Fabre, Daiichi Sankyo, Seagen, AstraZeneca, Eisai outside the submitted work. The other authors declare no conflict of interest. The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript and decision to submit the manuscript for publication. Registration number: N/A
\u201cThe use of Autologous Flaps in Breast Reshaping After Massive Weight Loss: A Systematic Review\u201d
Background: Massive weight loss (MWL) has a positive impact on the comorbidities associated with obesity but leaves patients with ongoing body issues due to skin excess. Almost all patients present some degree of breast ptosis and breast volume deficiency, which can be addressed with different techniques including autologous flaps. Material and Methods: A literature search was conducted by using PubMed, Google Scholar, and Cochrane databases. Patient's characteristics, type of bariatric surgery, amount of weight loss, flap size and design, simultaneous breast and extra-breast procedures were analyzed. Aesthetic and patient-reported outcomes, postoperative complications, revision rate, and donor site morbidity were also registered. Results: Twelve articles fulfilled inclusion criteria, and 79 patients were included, for a total of 157 flaps. Different flap designs and flap combinations were described; those originating from lateral chest wall area were the most commonly used. Simultaneous breast procedures were reported in 72 patients. Simultaneous extra-breast body contouring (BC) procedure was performed in 40 cases. The overall complication rate was 9.55% and a total of ten revisionary procedures were performed. Satisfaction of the patients was globally quite high. Conclusions: Advantages of the use of autologous tissue in breast reshaping after MWL is the avoidance of implant-related complications and the simultaneous improvement of the silhouette. The complication rate resulted in acceptable, aesthetic, and patient-reported outcomes resulted to be encouraging, even if there was a lack of standardization in the evaluation. A comparative randomized study to confront the use of autologous flaps combined with mastopexy versus the use of implants combined with mastopexy can be useful to confirm the promising results. Level of Evidence III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266
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