Search results for "frequency [modulation]"
showing 10 items of 569 documents
Seeding after radiofrequency ablation of hepatocellular carcinoma in patients with cirrhosis: a prospective study.
2008
Abstract Background Neoplastic seeding of hepatocellular carcinoma may arise after radiofrequency ablation. Aims In order to clarify the real risk of seeding, we observed a prospective cohort of patients undergoing radiofrequency ablation. Methods Ninety-three (22.9%) out of 406 consecutive patients with hepatocellular carcinoma superimposed to cirrhosis diagnosed at our Liver Unit (2000–2005) were selected for radiofrequency ablation according to the Barcelona 2000 EASL guidelines. Seventy-one patients were treated by a percutaneous approach and 22 at laparotomy. After radiofrequency ablation ultrasound scan was repeated every 3 months and spiral-computed tomography every 6 months. Results…
Reproductive and Obstetric Outcomes after UAE, HIFU, and TFA of Uterine Fibroids: Systematic Review and Meta-Analysis
2023
Novel treatment options for uterine fibroids, such as uterine artery embolization (UAE), ultrasound-guided and magnetic resonance-guided high-intensity focused ultrasound (USgHIFU and MRgHIFU), and transcervical radiofrequency ablation (TFA) methods, are widely used in clinical practice. This systematic review and meta-analysis (CRD42022297312) aims to assess and compare reproductive and obstetric outcomes in women who underwent these minimally invasive approaches for uterine fibroids. The search was performed in PubMed, Google Scholar, ScienceDirect, Cochrane Library, Scopus, Web of Science and Embase. Risk of bias was assessed using the Newcastle–Ottawa Scale (NOS) and Cochrane guidelines…
A wavelet analysis of US fiscal sustainability
2015
Abstract In this paper, we reassess the relationship between primary deficit and lagged debt to GDP ratio (Bohn, 1998), to test for US debt sustainability over the period 1795–2012. Our analysis is rooted in the wavelet domain enabling the detection of interesting patterns and otherwise hidden information. We find evidence of long term fiscal sustainability but only up until 1995 and also we show that governments tend to respond more vigorously to budget deficits when the level of debt is high rather than low.
A Novel Semi-Supervised Methodology for Extracting Tumor Type-Specific MRS Sources in Human Brain Data
2013
Background: The clinical investigation of human brain tumors often starts with a non-invasive imaging study, providing \ud information about the tumor extent and location, but little insight into the biochemistry of the analyzed tissue. Magnetic \ud Resonance Spectroscopy can complement imaging by supplying a metabolic fingerprint of the tissue. This study analyses \ud single-voxel magnetic resonance spectra, which represent signal information in the frequency domain. Given that a single \ud voxel may contain a heterogeneous mix of tissues, signal source identification is a relevant challenge for the problem of\ud tumor type classification from the spectroscopic signal.\ud Methodology/Princ…
Synthesis, crystal structure and magnetic properties of a novel heterobimetallic rhenium(IV)-dysprosium(III) chain.
2015
The use of the mononuclear rhenium(IV) precursor [ReBr5 (H2 pydc)](-) (H2 pydc=3,5-pyridinedicarboxylic acid) as a metalloligand towards dysprosium(III) afforded the first heterobimetallic Re(IV) -Dy(III) complex. Crystal structures and static and dynamic magnetic properties of both rhenium-containing species are reported herein. The 5d-4f compound shows an extended 1D structure and the AC magnetic measurements reveal frequency dependence at low temperature suggesting slow relaxation of the magnetization.
Oscillatory Dynamics Underlying Perceptual Narrowing of Native Phoneme Mapping from 6 to 12 Months of Age
2016
During the first months of life, human infants process phonemic elements from all languages similarly. However, by 12 months of age, as language-specific phonemic maps are established, infants respond preferentially to their native language. This process, known as perceptual narrowing, supports neural representation and thus efficient processing of the distinctive phonemes within the sound environment. Although oscillatory mechanisms underlying processing of native and non-native phonemic contrasts were recently delineated in 6-month-old infants, the maturational trajectory of these mechanisms remained unclear. A group of typically developing infants born into monolingual English families, …
The Effects of Attachment, Temperament, and Self-Esteem on Technology Addiction: A Mediation Model among Young Adults
2022
Excessive use of technology has become a worldwide problem due to its high prevalence, fast growth rate, and undesirable consequences. However, little is known about underlying psychological mechanisms that maintain excessive use of technology. We investigated the mediating role of self-esteem, novelty seeking, and persistence on the relationship between attachment dimensions and technology addiction among young adults. Data were collected from 727 young adults (females, N = 478; 66.3 percent), aged 23.44 ± 3.02 years. Participants completed self-report measures of secure and insecure attachment dimensions, personality, and temperament characteristics (i.e., self-esteem, novelty seeking, an…
Frequent use of sugar products by schoolchildren in 20 European countries, Israel and Canada in 1993/1994
1999
The aim of this study was to describe the daily use of certain between-meal sugar products (soft drinks and sweets) of schoolchildren in 20 European countries, Israel and Canada as a part of the Cross-National Survey on Health Behaviour in School-Aged Children--a WHO Collaborative Study. The data were collected using standardised anonymous questionnaires in school classrooms during the 1993/1994 school year. In each country nationally or regionally representative samples of about 1,300 schoolchildren (450 in Greenland) were targeted. Use of sugar products was analysed according to sex, age, country, self-reported school performance and self-reported family economy. One third to one half of …
Effectiveness of Pulsed Radiofrequency with Multifunctional Epidural Electrode in Chronic Lumbosacral Radicular Pain with Neuropathic Features
2014
Lumbosacral radicular pain is a common clinical finding with a statistical prevalence ranging from 9.9% to 25% in the general population.To investigate the effectiveness of dorsal root ganglion pulsed radiofrequency (PRF) in patients with chronic lumbosacral radicular pain and neuropathic features.Prospective case series clinical outcome study.We evaluated 34 patients with lumbosacral neuropathic pain who underwent PRF at the corresponding level of radicular symptoms distribution (ranging from L3 to S1). Each patient suffered a single leg-radiating pain with probable neuropathic features (assessed with clinical grading) lasting for6 months and unresponsive to previous treatments. A multifun…
The effect of alertness and attention on the modulation of the beta rhythm to tactile stimulation
2021
Abstract Beta rhythm modulation has been used as a biomarker to reflect the functional state of the sensorimotor cortex in both healthy subjects and patients. Here, the effect of reduced alertness and active attention to the stimulus on beta rhythm modulation was investigated. Beta rhythm modulation to tactile stimulation of the index finger was recorded simultaneously with MEG and EEG in 23 healthy subjects (mean 23, range 19–35 years). The temporal spectral evolution method was used to obtain the peak amplitudes of beta suppression and rebound in three different conditions (neutral, snooze, and attention). Neither snooze nor attention to the stimulus affected significantly the strength of…