west china medical publishers
Keyword
  • Title
  • Author
  • Keyword
  • Abstract
Advance search
Advance search

Search

find Keyword "frequency" 190 results
  • Abnormal spontaneous brain functional activity in adult patients with amblyopia: a resting-state functional magnetic resonance imaging study

    Amblyopia is a visual development deficit caused by abnormal visual experience in early life, mainly manifesting as defected visual acuity and binocular visual impairment, which is considered to reflect abnormal development of the brain rather than organic lesions of the eye. Previous studies have reported abnormal spontaneous brain activity in patients with amblyopia. However, the location of abnormal spontaneous activity in patients with amblyopia and the association between abnormal brain function activity and clinical deficits remain unclear. The purpose of this study is to analyze spontaneous brain functional activity abnormalities in patients with amblyopia and their associations with clinical defects using resting-state functional magnetic resonance imaging (fMRI) data. In this study, 31 patients with amblyopia and 31 healthy controls were enrolled for resting-state fMRI scanning. The results showed that spontaneous activity in the right angular gyrus, left posterior cerebellum, and left cingulate gyrus were significantly lower in patients with amblyopia than in controls, and spontaneous activity in the right middle temporal gyrus was significantly higher in patients with amblyopia. In addition, the spontaneous activity of the left cerebellum in patients with amblyopia was negatively associated with the best-corrected visual acuity of the amblyopic eye, and the spontaneous activity of the right middle temporal gyrus was positively associated with the stereoacuity. This study found that adult patients with amblyopia showed abnormal spontaneous activity in the angular gyrus, cerebellum, middle temporal gyrus, and cingulate gyrus. Furthermore, the functional abnormalities in the cerebellum and middle temporal gyrus may be associated with visual acuity defects and stereopsis deficiency in patients with amblyopia. These findings help explain the neural mechanism of amblyopia, thus promoting the improvement of the treatment strategy for amblyopia.

    Release date:2022-10-25 01:09 Export PDF Favorites Scan
  • Intraoperative Saline-irrigated Radiofrequency Modified Maze Procedure for Chronic Atrial Fibrillation in Mitral Valve Diseases

    Objective To report the preliminary results of intraoperative saline-irrigated radiofrequency modified maze procedure for chronic atrial fibrillation (AF) in mitral valve diseases. Methods From May 2003 to April 2004 forty-one patients underwent intraoperative saline-irrigated modified maze procedure. The patients included 13 male and 28 female. Their age ranged from 27-65 years (46±10 years). The duration of AF varied from 5 months to 15 years (4.5±3.6 years).The left atrial diameter varied from 37-93 mm (54±11mm). There were mitral stenosis 20, mitral regurgitation 1 and mitral stenosis with regurgitation 20 cases. Cardiopulmonary bypass (CPB) was established as usual. Ablation lines were made with Cardioblate (Medtronic, 25-30 W, 180-240ml/h). Having finished right-sided maze procedure, the aorta was cross-clamped and cold crystalloid or blood cardioplegia were used for myocardial protection. Left atrial incision was performed through the interatrial groove. The ablation lines were created to encircle the orifices of the left and right pulmonary veins respectively. The ablation lines were also performed from the left encircling line to the posterior mitral valvular annulus and to the orifice of left atrial appendage respectively. A ablation line was used to connect left and right pulmonary veins circumferential line. Concomitant procedures were performed (there were double valve replacement 10 cases, mitral valve replacement 31 cases, tricuspid annuloplasty 6 cases, removing the left atrial thrombi 6 cases). Results CPB time varied from 71-160 min (105±24 min) and cross-clamping time varied from 32-106 min (62±20 min). The ablation time varied from 4-22 min (11±4 min). One patient died during hospitalization and the death was caused by acute mechanic valve obstruction. During follow-up at discharge and 3 months 35% patients (14/40) were free of AF and the others were not. But at 6 months 67% patients (10/15) were free of AF. Conclusion The intraoperative saline-irrigated radiofrequency modified maze procedure is comparatively simpler and its efficacy is satisfactory.

    Release date:2016-08-30 06:25 Export PDF Favorites Scan
  • APPLICATION OF ISOIONIC MICROTRAUMA ARTHROSCOPE ON TREATMENT OF KNEE ARTHROPATHY

    Objective To investigate the clinical applicationand curative effect of isoionic microtrauma arthroscope on treatment of knee arthropathy. Methods From May 2003 to November 2004, 52 cases of knee joint injury were cured by using isoionic microtrauma arthroscope, including 30 cases ofknee osteoarthritis, 10 cases of meniscus injury, 5 cases of kneecap dislocation, 5 cases of laxity of anterior cruciate ligation and 2 cases of rheumatoid arthritis. In accordance with Lysholm criterion for knee joint function, the scores were 35.5±4.9 before operation. Results All of these patients were followed up for 2-17 months. The scores of knee joint function was 86.4±5.3 after operation, and there was significant difference (Plt;0.001). Conclusion Isoionic microtrauma arthroscope is characterized by low-temperature hemoagglutination, crimpling,boiling, cutting and hemostasia, which makes kneejoint arthroscope operation easier-to-do, miner histological scathe and lighter side effect; so it is favourable for functional recovery and its curative effect is satisfactory.

    Release date:2016-09-01 09:30 Export PDF Favorites Scan
  • Radiofrequency Volumetric Tissue Reduction in the Treatment of Sleep Disordered Breathing: A Systematic Review

    Objective To evaluate the effectiveness ofradiofrequency volumetric tissue reduction (RFVTR) in the treatment of sleep disordered breathing (SDB ). Methods We searched The Cochrane Central Register of Controlled Trials (Issue 1, 2005), MEDLINE (1966 to Apr. 2005), EMBASE (1989 to Apr. 2005), CINAHL (1982 to Dec. 2000), VIP (1989 to Dec. 2004) , CJFD (1979 to 2005), WANFANG DATA (1977 to 2004) , and CBMdisc (1978 to 2005). The bibliographies of all papers retrieved in full text form and relevant narrative reviews were searched for additional publications. All randomized controlled clinical trials (RCT) or quasi-randomized controlled trials (quasi-RCT) or prospective cohort studies of RFVTR alone or in combination with other treatments compared with placebo or other treatments were included. Data were extracted independently from the trial reports by the two authors. Meta-analysis was performed using RevMan software. Results There were 11 studies including 540 patients met the inclusion criteria for this review, among which five were RCTs, six were prospective cohort studies, and all trials were of lower methodological quality. RFVTR showed benefit over placebo in apnea index (AI), but this benefit was not seen in other polysorrmography (PSG) parameters, symptom and quality of life, psychomotor vigilance pain, swallowing difficulty and adverse events. Compared with continuous positive airway pressure (CPAP), uvulopalatopharyngoplasty (UPPP) and laser assisted uvulopalatoplasty (LAUP) , RFVTR was more effective in psychomotor vigilance pain and swallowing difficulty, but this effect was not seen in PSG parameters, symptom and quality of life. Conclusions RFVTR is more effective than placebo in AI improvement and other treatments in decreasing postoperative pain and other adverse events ; but this benefit was not seen in improving quality of sleeping and life. More well-designed randomized trials need to be conducted to identify the effectiveness and the influence on effectiveness of severity and frequency of treatment.

    Release date:2016-09-07 02:25 Export PDF Favorites Scan
  • Gravity Frequency and Its Monitoring Application of EEG Spectrum in the Vigilance Operation

    It is an important means to study the electrical activity of the brain's nerve cells by exploring physiological information of the EEGs from the frequency domain. The gravity frequency is one of the global parameters with using this method. We used the multitaper spectrum method (MTM) spectrum estimation method of good performance to calculate the EEG spectrum and its gravity frequency of subjects under vigilance and vigilance decrement state. The results showed that the gravity frequency of vigilance state was higher than that of vigilance decrement state, the gravity frequency became smaller along with the vigilance decrement, and the location of the gravity frequency shifted to the left in the spectrum. Finally, the monitoring curve of the gravity frequency was acquired by designing an algorithm, and it was used to online monitoring vigilance operators.

    Release date: Export PDF Favorites Scan
  • Multi-task motor imagery electroencephalogram classification based on adaptive time-frequency common spatial pattern combined with convolutional neural network

    The effective classification of multi-task motor imagery electroencephalogram (EEG) is helpful to achieve accurate multi-dimensional human-computer interaction, and the high frequency domain specificity between subjects can improve the classification accuracy and robustness. Therefore, this paper proposed a multi-task EEG signal classification method based on adaptive time-frequency common spatial pattern (CSP) combined with convolutional neural network (CNN). The characteristics of subjects' personalized rhythm were extracted by adaptive spectrum awareness, and the spatial characteristics were calculated by using the one-versus-rest CSP, and then the composite time-domain characteristics were characterized to construct the spatial-temporal frequency multi-level fusion features. Finally, the CNN was used to perform high-precision and high-robust four-task classification. The algorithm in this paper was verified by the self-test dataset containing 10 subjects (33 ± 3 years old, inexperienced) and the dataset of the 4th 2018 Brain-Computer Interface Competition (BCI competition Ⅳ-2a). The average accuracy of the proposed algorithm for the four-task classification reached 93.96% and 84.04%, respectively. Compared with other advanced algorithms, the average classification accuracy of the proposed algorithm was significantly improved, and the accuracy range error between subjects was significantly reduced in the public dataset. The results show that the proposed algorithm has good performance in multi-task classification, and can effectively improve the classification accuracy and robustness.

    Release date:2023-02-24 06:14 Export PDF Favorites Scan
  • Comparative Study on Primary Journals Titled "Evidence-Based"

    Objective To compare articles published in global primary journals titled “evidence-based” via bibliometric analysis in order to provide suggestion for evidence-based research and development of related journals. Methods We searched electronic databases to retrieve global primary journals titled “evidence-based”, and collected their impact factors, article click, download and citation frequency through the journal’s website and related citation databases. Results Three English and 4 Chinese primary journals titled “evidence-based” met the inclusion criteria. (1) Citation frequency: Evidence-Based Complementary amp; Alternative Medicine and Worldviews on Evidence-Based Nursing were indexed by SCI with impact factor over 1 (5th and 13th in relevant subject category), and their immediacy index was about 7 times as much as that of Chinese journals (0.2 vs 0.03). Chinese Journal of Evidence-Based Pediatrics (CJEBP) had the highest impact factor among 4 Chinese journals (0.946, 23rd in the relevant subject category), while Chinese Journal of Evidence-Based Medicine had the highest immediacy index with 0.07; (2) Download frequency: Journal of Evidencebased Medicine (JEBM) had the highest download frequency per article in database (72 vs 23), but the website download frequencies per article of CJEBM and CJEBP were about 5 to 6 times as much as that of database; (3) Number of articles published: Two English journals published the fewest articles but with the highest impact factors. Chinese Journal of Evidence-Based Medicine had the 2nd highest impact factor although published the most articles, as well as the highest download frequency and immediacy index among the 4 Chinese journals. It suggested that there was no direct relationship between the number of the published articles and the impact factor of a journal. Conclusion The impact of English journals is better than that of Chinese journals. CJEBM and CJEBP are the top 2 ones among the Chinese journals with open access websites. The selection of articles should be driven by readers’ demand, and the impact of journals could be improved by online publication with open access.

    Release date:2016-09-07 11:23 Export PDF Favorites Scan
  • Impact of Ultrasound-Guided Acetic Acid Hypertonic Saline Solution Injection on Radiofrequency Ablation Destructive Zone in Dog Liver

    Objective To investigate the impact of injection of acetic acid hypertonic saline solution (AHS) in dog liver during radiofrequency ablation (RFA) on its destructive zone. Methods RFAs were performed in dog livers by using LDRF-120S mutiple probe ablation system combining 50% acetic acid 5% hypertonic saline solution injection. Thirty healthy adult hybrid dogs were randomly divided into 5 groups (n=6). Group A: RFA was performed immediately after injection of 2 ml AHS; Group B: RFA was performed 5 min after injection of 2 ml AHS; Group C: RFA was performed immediately after injection of 4 ml AHS; Group D: RFA was performed 5 min after injection of 4 ml AHS; Group E: RFA was performed immediately after injection of 6 ml AHS. Results There were no significant differences in the mean initial impedance within 5 groups. The mean ablation times were different significantly among 5 groups (F=83.831, P<0.001). The mean ablation time was different significantly between any two groups by LSD-t analysis (P<0.001). The mean coagulation diameters were different significantly among 5 groups (F=53.488, P<0.001). The mean coagulation diameter of group E was the largest among 5 groups. Besides mean coagulation diameter was no significant difference between group D and E (Pgt;0.05), the mean coagulation diameter was different significantly between any two groups by LSD-t analysis (P<0.001). Obviously thrombus were shown in coagulation necrosis zone and nearly normal tissue with gordon amp; sweet. AHS spillage from the injection site occurred in group E. Four dogs died in group E within 14 d but no dog died in the other groups. Conclusion RFA is performed 5 min after injection of 4 ml AHS in dog liver produces the ideal ablation destructive zone.

    Release date:2016-09-08 11:49 Export PDF Favorites Scan
  • High frequency stimulations change the phase-locking relationship between neuronal firing and the rhythms of field potentials

    Deep brain stimulation (DBS) has been successfully used to treat a variety of brain diseases in clinic. Recent investigations have suggested that high frequency stimulation (HFS) of electrical pulses used by DBS might change pathological rhythms in action potential firing of neurons, which may be one of the important mechanisms of DBS therapy. However, experimental data are required to confirm the hypothesis. In the present study, 1 min of 100 Hz HFS was applied to the Schaffer collaterals of hippocampal CA1 region in anaesthetized rats. The changes of the rhythmic firing of action potentials from pyramidal cells and interneurons were investigated in the downstream CA1 region. The results showed that obvious θ rhythms were present in the field potential of CA1 region of the anesthetized rats. The θ rhythms were especially pronounced in the stratum radiatum. In addition, there was a phase-locking relationship between neuronal spikes and the θ rhythms. However, HFS trains significantly decreased the phase-locking values between the spikes of pyramidal cells and the θ rhythms in stratum radiatum from 0.36 ± 0.12 to 0.06 ± 0.04 (P < 0.001, paired t-test, N = 8). The phase-locking values of interneuron spikes were also decreased significantly from 0.27 ± 0.08 to 0.09 ± 0.05 (P < 0.01, paired t-test, N = 8). Similar changes were obtained in the phase-locking values between neuronal spikes and the θ rhythms in the pyramidal layer. These results suggested that axonal HFS could eliminate the phase-locking relationship between action potentials of neurons and θ rhythms thereby changing the rhythmic firing of downstream neurons. HFS induced conduction block in the axons might be one of the underlying mechanisms. The finding is important for further understanding the mechanisms of DBS.

    Release date:2018-02-26 09:34 Export PDF Favorites Scan
  • High-frequency ultrasounic observation of localization and operation accuracy of traditional blind acupotomy lysis in treatment of scapulohumeral periarthritis

    ObjectiveTo observe the accuracy of location and operation of traditional blind acupotomy lysis in the treatment of scapulohumeral periarthritis by using the high-frequency ultrasound.MethodsForty-two patients with scapulohumeral periarthritis diagnosed in the First Affiliated Hospital of Xinjiang Medical University and Urumqi Hospital of Traditional Chinese Medicine from February to April 2018 were selected. Four common sites of needle knife in the treatment of scapulohumeral periarthritis were operated blindly, and the process of the needle insertion points location and needle perform were both observed by high-frequency ultrasound.ResultsUsing high-frequency ultrasound to observe and confirm the bare-handed positioning point and needle-knife operating point, we found that the accuracy rate of bare-handed positioning needle-point was 100.0% (42/42). In the process of needling, the accuracies of needle insertion at the point of small tubercle of humerus and the point of bursa of deltoid muscle were high, which was 95.2% (40/42) and 100.0% (42/42), respectively. However, because of the deviation of the needle depth and direction, the accuracies of needle insertion at the coracoid point and the sulcus point between the humeral tubercles were low, which was 45.2% (19/42) and 4.8% (2/42), respectively.ConclusionsTraditional acupotomy lysis is a commonly used method of needle knife treatment. Using high-frequency ultrasound, it is found that even by experienced needle knife doctors, there may still be positioning deviation when using blind method to insert needles. Because the visualization of clinical needle knife is difficult to be carried out universally due to the limitations of time and technology, it is suggested that high-frequency ultrasound could be used as a visualization teaching tool in the training of needle knife operation to assist the training of blind needle knife operation technology, which may improve the accuracy of blind needle knife operation.

    Release date:2018-10-22 04:14 Export PDF Favorites Scan
19 pages Previous 1 2 3 ... 19 Next

Format

Content