Search results for "stage"
showing 10 items of 1393 documents
Deterministic chaos and the first positive Lyapunov exponent: a nonlinear analysis of the human electroencephalogram during sleep
1993
Under selected conditions, nonlinear dynamical systems, which can be described by deterministic models, are able to generate so-called deterministic chaos. In this case the dynamics show a sensitive dependence on initial conditions, which means that different states of a system, being arbitrarily close initially, will become macroscopically separated for sufficiently long times. In this sense, the unpredictability of the EEG might be a basic phenomenon of its chaotic character. Recent investigations of the dimensionality of EEG attractors in phase space have led to the assumption that the EEG can be regarded as a deterministic process which should not be mistaken for simple noise. The calcu…
The calculation of the first positive Lyapunov exponent in sleep EEG data
1993
To help determine if the EEG is quasiperiodic or chaotic we performed a new analysis by calculating the first positive Lyapunov exponent L1 from sleep EEG data. Lyapunov exponents measure the mean exponential expansion or contraction of a flow in phase space. L1 is zero for periodic as well as quasiperiodic processes, but positive in case of chaotic processes expressing the sensitive dependence on initial conditions. We calculated L1 for sleep EEG segments of 15 healthy male subjects corresponding to sleep stages I, II, III, IV and REM (according to Rechtschaffen and Kales). Our investigations support the assumption that EEG signals are neither quasiperiodic waves nor simple noise. Moreover…
Estimation of the age of majority through radiographic evaluation of the third molar maturation degree
2020
Background Although the third molar is the tooth with the greatest anatomical and developmental variability, some authors consider it important to estimate whether a subject is of legal age or not. The Demirjian’s technique is the most widely used tool to estimate dental age and was therefore used in our study to assess possible correlation between the age of majority and the maturational degree of the lower third molars, evaluated through radiographic images. Material and Methods This observational transversal study was conducted on 180 panoramic radiographs from consecutive patients. The degree of maturation of the lower third molar was independently classified by two observers, according…
Physical activity, healthy behaviors and its motivational correlates: exploring the spillover effect through stages of change
2022
On the basis of the spillover or transfer effect and the transtheoretical model of change, this study assessed the association between amount of physical activity, healthy and unhealthy weight control behaviors, and motivational types, as well as their variability across stages of change. A total of 1219 randomly selected Mexican adults from 18 to 65 years old, representative of the city of Monterrey (México), participated in the study. Correlation analyses, differences by gender, and multivariate analyses of variance, controlling for age, were performed. We found that in the maintenance stage, there is higher frequency of physical activity more healthy weight control behaviors, as well as …
NK/T-cell lymphomas 'nasal type': an italian multicentric retrospective survey
2006
Abstrac Objective: To evaluate the clinical characteristics and outcome of NK/T-cell lymphoma ‘nasal type’ developed in Italian patients. Patients: Between 1997 and 2004, 26 new cases of NK/T-cell lymphoma ‘nasal type’ were diagnosed in 10 Italian Hematology institutions. Results: All patients were Caucasian, male/female ratio was 19/7, with a median age of 50 years (range 20–80). In 23 cases presentation at the onset was in the nasal cavity or adjacent structures, in two cases the lymphoma onset with skin lesions was followed successively by rhynopharyngeal dissemination, while the remaining case had bone marrow and lymph node involvement followed by oro-pharyngeal involvement. Regarding t…
Plasticity of brain wave network interactions and evolution across physiologic states
2015
Neural plasticity transcends a range of spatio-temporal scales and serves as the basis of various brain activities and physiologic functions. At the microscopic level, it enables the emergence of brain waves with complex temporal dynamics. At the macroscopic level, presence and dominance of specific brain waves is associated with important brain functions. The role of neural plasticity at different levels in generating distinct brain rhythms and how brain rhythms communicate with each other across brain areas to generate physiologic states and functions remains not understood. Here we perform an empirical exploration of neural plasticity at the level of brain wave network interactions repre…
Subchronic Effects of Olanzapine on Sleep EEG in Schizophrenic Patients with Predominantly Negative Symptoms
2004
Background It is well known that sleep disturbance is an integral symptom of schizophrenia. In recent studies, a deficit of delta sleep has been observed in schizophrenic patients. Antipsychotic drugs with serotonin (5-HT2) receptor-antagonistic properties are considered to have delta sleep promoting effects. We have investigated the effects of subchronic olanzapine treatment on sleep EEG in schizophrenic patients. Methods The effects of administration of olanzapine (15 to 20 mg) on sleep were studied for four weeks in 10 male, drug-free patients suffering from schizophrenia with predominantly negative symptoms. Conventional sleep EEG parameters were investigated at baseline and after treat…
Promyelocytic leukemia (PML) gene expression is a prognostic factor in ampullary cancer patients
2008
Background: Promyelocytic leukemia (PML) tumor suppressor gene plays a key role in acute PML pathogenesis but its involvement in pathogenesis and prognosis of solid cancers has not been defined yet. Patients and methods: In all, 62 ampullary adenocarcinoma patients who underwent curative surgery between 1996 and 2005 were included. Expression analysis of PML was carried out by immunohistochemical staining and correlated with disease-free survival (DFS) and overall survival (OS). Results: In 24 tumor specimens (38.7%), PML was classified as absent, in 16 (25.8%) as focally expressed and in 22 (35.5%) as diffusely expressed. By univariate analysis, DFS was significantly influenced by patholog…
Osteonecrosis of the jaw related to non-antiresorptive medications: a systematic review
2018
The reporting of osteonecrosis of the jaw (ONJ) related to anticancer agents without known antiresorptive properties (non-antiresorptives), such as antiangiogenics, tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, immune checkpoint inhibitors, and cytotoxic chemotherapy is increasing. To review characteristics of ONJ in cancer patients receiving non-antiresorptives. A systematic review of the literature between 2009 and 2017 was conducted by the Bone Study Group of MASCC/ISOO. Of 6249 articles reviewed and from personal communication, 42 ONJ cases related to non-antiresorptives were identified. No gender predilection was noted. Median age was 60 years and ONJ stage 2 wa…
Small renal cell carcinomas – How dangerous are they really? Results of a large multicenter study
2013
Modern diagnostic ultrasound and cross-sectional imaging has enabled the detection of increasing numbers of renal tumours. The aim of this study was to investigate the tumour- and patient-specific characteristics and prognosis of small renal cell carcinomas (RCCs) after surgical resection.The study included 2197 patients who underwent surgical resection of histologically confirmed RCC ⩽ 4 cm between 1990 and 2011. Median (mean) follow-up was 56.2 (65.5) months.At the time of surgery, tumours were staged as pT ⩾ 3a in 175 (8.0%) cases, 134 (6.2%) were poorly differentiated and 75 (3.5%) were metastasised. The larger the tumour size, the higher was the risk of presenting with stage pT ⩾ 3a (p…