371 research outputs found
The spatio-temporal spectrum of turbulent flows
Identification and extraction of vortical structures and of waves in a
disorganised flow is a mayor challenge in the study of turbulence. We present a
study of the spatio-temporal behavior of turbulent flows in the presence of
different restitutive forces. We show how to compute and analyse the
spatio-temporal spectrum from data stemming from numerical simulations and from
laboratory experiments. Four cases are considered: homogeneous and isotropic
turbulence, rotating turbulence, stratified turbulence, and water wave
turbulence. For homogeneous and isotropic turbulence, the spectrum allows
identification of sweeping by the large scale flow. For rotating and for
stratified turbulence, the spectrum allows identification of the waves, precise
quantification of the energy in the waves and in the turbulent eddies, and
identification of physical mechanisms such as Doppler shift and wave absorption
in critical layers. Finally, in water wave turbulence the spectrum shows a
transition from gravity-capillary waves to bound waves as the amplitude of the
forcing is increased.Comment: Added new references and analysi
A rule-free workflow for the automated generation of databases from scientific literature
In recent times, transformer networks have achieved state-of-the-art
performance in a wide range of natural language processing tasks. Here we
present a workflow based on the fine-tuning of BERT models for different
downstream tasks, which results in the automated extraction of structured
information from unstructured natural language in scientific literature.
Contrary to existing methods for the automated extraction of structured
compound-property relations from similar sources, our workflow does not rely on
the definition of intricate grammar rules. Hence, it can be adapted to a new
task without requiring extensive implementation efforts and knowledge. We test
our data-extraction workflow by automatically generating a database for Curie
temperatures and one for band gaps. These are then compared with
manually-curated datasets and with those obtained with a state-of-the-art
rule-based method. Furthermore, in order to showcase the practical utility of
the automatically extracted data in a material-design workflow, we employ them
to construct machine-learning models to predict Curie temperatures and band
gaps. In general we find that, although more noisy, automatically extracted
datasets can grow fast in volume and that such volume partially compensates for
the inaccuracy in downstream tasks.Comment: 19 pages, 11 figure
Deep learning radiomic nomogram can predict the number of lymph node metastasis in locally advanced gastric cancer: an international multi-center study.
BACKGROUND: Preoperative evaluation of the number of lymph node metastasis (LNM) is the basis of individual treatment of locally advanced gastric cancer (LAGC). However, the routinely used preoperative determination method is not accurate enough. PATIENTS AND METHODS: We enrolled 730 LAGC patients from 5 centers in China and 1 center in Italy, and divided them into 1 primary cohort, 3 external validation cohorts, and 1 international validation cohort. A deep learning radiomic nomogram (DLRN) was built based on the images from multi-phase computed tomography (CT) for preoperatively determining the number of LNM in LAGC. We comprehensively tested the DLRN and compared it with three state-of-the-art methods. Moreover, we investigated the value of the DLRN in survival analysis. RESULTS: The DLRN showed good discrimination of the number of LNM on all cohorts (overall C-indexes: 0.821, 95% CI: 0.785-0.858 in the primary cohort; 0.797, 95% CI: 0.771-0.823 in the external validation cohorts; and 0.822, 95% CI: 0.756-0.887 in the international validation cohort). The nomogram performed significantly better than the routinely used clinical N stages, tumor size, and clinical model (p<0.05). Besides, DLRN is significantly associated with the overall survival of LAGC patients (n=271). CONCLUSION: A deep learning-based radiomic nomogram had good predictive value for LNM in LAGC. In staging-oriented treatment of gastric cancer, this preoperative nomogram could provide baseline information for individual treatment of LAGC
Radical penectomy, a compromise for life: Results from the PECAD study
Background: The use of organ sparing strategies to treat penile cancer (PC) is currently supported by evidence that has indicated the safety, efficacy and benefit of this surgery. However, radical penectomy still represents up to 15-20% of primary tumor treatments in PC patients. The aim of the study was to evaluate efficacy in terms of overall survival (OS) and disease-free survival (DFS) of radical penectomy in PC patients.Methods: Data from a retrospective multicenter study (PEnile Cancer ADherence study, PECAD Study) on PC patients treated at 13 European and American urological centers (Hospital "Sant'Andrea", Sapienza University, Roma, Italy; "G.D'Annunzio" University, Chieti and ASL 2 Abruzzo, Hospital "S. Pio da Pietrelcina", Vasto, Italy; Department of Genitourinary Oncology, Moffitt Cancer Center, Tampa, FL, USA; Hospital of Budapest, Hungary; Department of Emergency and Organ Transplantation, Urology and Andrology Unit II, University of Bari, Italy; Hospital "Spedali Civil", Brescia, Italy; Istituto Europeo di Oncologia, University of Milan, Milan, Italy; University of Modena & Reggio Emilia, Modena, Italy; Hospital Universitario La Paz, Madrid, Spain; Ceara Cancer Institute, Fortaleza, Brazil; Virginia Commonwealth University, Richmond, VA, USA; Aristotle University of Thessaloniki, Thessaloniki, Greece; Maria Sklodowska-Curie Memorial Cancer Center, Warsaw, Poland) between 2010 and 2016 were used. Medical records of patients who specifically underwent radical penectomy were reviewed to identify main clinical and pathological variables. Kaplan-Meier method was used to estimate 1- and 5-year OS and DFS.Results: Of the entire cohort of 425 patients, 72 patients (16.9%) treated with radical penectomy were extracted and were considered for the analysis. The median age was 64.5 (IQR, 57.5-73.2) years. Of all, 41 (56.9%) patients had pT3/pT4 and 31 (43.1%) pT1/pT2. Moreover, 36 (50.0%) were classified as pN1-3 and 5 (6.9%) MI. Furthermore, 61 (84.7%) had a high grade (G2-G3) with 6 (8.3%) positive surgical margins. The 1- and 5-year OS rates were respectively 73.3% and 59.9%, while the 1- and 5-year DFS rates were respectively 67.3% and 35.1%.Conclusions: PC is an aggressive cancer particularly in more advanced stage. Overall, more than a third of patients do not survive at 5 years and more than 60% report a disease recurrence, despite the use of a radical treatment
Common Genetic Variation in GLP1R and Insulin Secretion in Response to Exogenous GLP-1 in Nondiabetic Subjects: A pilot study
OBJECTIVE:
Glucagon-like peptide (GLP)-1 receptor is encoded by GLP1R. The effect of genetic variation at this locus on the response to GLP-1 is unknown. This study assessed the effect of GLP1R polymorphisms on insulin secretion in response to hyperglycemia and to infused GLP-1 in nondiabetic subjects.
RESEARCH DESIGN AND METHODS:
Eighty-eight healthy individuals (aged 26.3 +/- 0.6 years, fasting glucose 4.83 +/- 0.04 mmol/l) were studied using a hyperglycemic clamp. GLP-1 was infused for the last 2 h of the study (0.75 pmol/kg/min over 121-180 min, 1.5 pmol/kg/min over 181-240 min). beta-Cell responsivity (Phi(Total)) was measured using a C-peptide minimal model. The effect of 21 tag single nucleotide polymorphisms (SNPs) in GLP1R on Phi(Total) was examined.
RESULTS:
Two SNPs (rs6923761 and rs3765467) were nominally associated with altered beta-cell responsivity in response to GLP-1 infusion.
CONCLUSIONS:
Variation in GLP1R may alter insulin secretion in response to exogenous GLP-1. Future studies will determine whether such variation accounts for interindividual differences in response to GLP-1-based therapy
Radical penectomy, a compromise for life. Results from the PECAD study
Background: The use of organ sparing strategies to treat penile cancer (PC) is currently supported by evidence that has indicated the safety, efficacy and benefit of this surgery. However, radical penectomy still represents up to 15-20% of primary tumor treatments in PC patients. The aim of the study was to evaluate efficacy in terms of overall survival (OS) and disease-free survival (DFS) of radical penectomy in PC patients. Methods: Data from a retrospective multicenter study (PEnile Cancer ADherence study, PECAD Study) on PC patients treated at 13 European and American urological centers (Hospital “Sant'Andrea”, Sapienza University, Roma, Italy; “G.D'Annunzio” University, Chieti and ASL 2 Abruzzo, Hospital “S. Pio da Pietrelcina”, Vasto, Italy; Department of Genitourinary Oncology, Moffitt Cancer Center, Tampa, FL, USA; Hospital of Budapest, Hungary; Department of Emergency and Organ Transplantation, Urology and Andrology Unit II, University of Bari, Italy; Hospital “Spedali Civili”, Brescia, Italy; Istituto Europeo di Oncologia, University of Milan, Milan, Italy; University of Modena & Reggio Emilia, Modena, Italy; Hospital Universitario La Paz, Madrid, Spain; Ceara Cancer Institute, Fortaleza, Brazil; Virginia Commonwealth University, Richmond, VA, USA; Aristotle University of Thessaloniki, Thessaloniki, Greece; Maria Skłodowska-Curie Memorial Cancer Center, Warsaw, Poland) between 2010 and 2016 were used. Medical records of patients who specifically underwent radical penectomy were reviewed to identify main clinical and pathological variables. Kaplan-Meier method was used to estimate 1- and 5-year OS and DFS. Results: Of the entire cohort of 425 patients, 72 patients (16.9%) treated with radical penectomy were extracted and were considered for the analysis. The median age was 64.5 (IQR, 57.5-73.2) years. Of all, 41 (56.9%) patients had pT3/pT4 and 31 (43.1%) pT1/pT2. Moreover, 36 (50.0%) were classified as pN1-3 and 5 (6.9%) M1. Furthermore, 61 (84.7%) had a high grade (G2-G3) with 6 (8.3%) positive surgical margins. The 1- and 5-year OS rates were respectively 73.3% and 59.9%, while the 1- and 5-year DFS rates were respectively 67.3% and 35.1%. Conclusions: PC is an aggressive cancer particularly in more advanced stage. Overall, more than a third of patients do not survive at 5 years and more than 60% report a disease recurrence, despite the use of a radical treatment
A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone
Recommended standardized procedures for determining exhaled lower respiratory
nitric oxide and nasal nitric oxide have been developed by task forces of the
European Respiratory Society and the American Thoracic Society. These
recommendations have paved the way for the measurement of nitric oxide to
become a diagnostic tool for specific clinical applications. It would be
desirable to develop similar guidelines for the sampling of other trace gases
in exhaled breath, especially volatile organic compounds (VOCs) which reflect
ongoing metabolism. The concentrations of water-soluble, blood-borne substances
in exhaled breath are influenced by: (i) breathing patterns affecting gas
exchange in the conducting airways; (ii) the concentrations in the
tracheo-bronchial lining fluid; (iii) the alveolar and systemic concentrations
of the compound. The classical Farhi equation takes only the alveolar
concentrations into account. Real-time measurements of acetone in end-tidal
breath under an ergometer challenge show characteristics which cannot be
explained within the Farhi setting. Here we develop a compartment model that
reliably captures these profiles and is capable of relating breath to the
systemic concentrations of acetone. By comparison with experimental data it is
inferred that the major part of variability in breath acetone concentrations
(e.g., in response to moderate exercise or altered breathing patterns) can be
attributed to airway gas exchange, with minimal changes of the underlying blood
and tissue concentrations. Moreover, it is deduced that measured end-tidal
breath concentrations of acetone determined during resting conditions and free
breathing will be rather poor indicators for endogenous levels. Particularly,
the current formulation includes the classical Farhi and the Scheid series
inhomogeneity model as special limiting cases.Comment: 38 page
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