780 research outputs found

    Performance of a Self-Paced Brain Computer Interface on Data Contaminated with Eye-Movement Artifacts and on Data Recorded in a Subsequent Session

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    The performance of a specific self-paced BCI (SBCI) is investigated using two different datasets to determine its suitability for using online: (1) data contaminated with large-amplitude eye movements, and (2) data recorded in a session subsequent to the original sessions used to design the system. No part of the data was rejected in the subsequent session. Therefore, this dataset can be regarded as a “pseudo-online” test set. The SBCI under investigation uses features extracted from three specific neurological phenomena. Each of these neurological phenomena belongs to a different frequency band. Since many prominent artifacts are either of mostly low-frequency (e.g., eye movements) or mostly high-frequency nature (e.g., muscle movements), it is expected that the system shows a fairly robust performance over artifact-contaminated data. Analysis of the data of four participants using epochs contaminated with large-amplitude eye-movement artifacts shows that the system's performance deteriorates only slightly. Furthermore, the system's performance during the session subsequent to the original sessions remained largely the same as in the original sessions for three out of the four participants. This moderate drop in performance can be considered tolerable, since allowing artifact-contaminated data to be used as inputs makes the system available for users at ALL times

    In Vitro Effect of Zirconia and Zirconia Enriched Glass Fiber Composite Posts on Fracture Resistance of Endodontically Treated Teeth

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    Objective: Despite the advantages of esthetic posts, lack of studies on their fracture resistance has limited their clinical use. This study aimed to compare the effect of two types of esthetic posts namely zirconia and zirconia enriched glass fiber composite posts on fracture resistance of endodontically treated teeth against compressive forces.Methods: This in vitro study was conducted on 20 mandibular premolar roots cut at the cementoenamel junction (CEJ). The roots were endodontically treated and randomly divided into 2 groups of 10. After post space preparation, in group 1 zirconia posts (CosmoPost, Ivoclar, Liechtenstein) and in group 2 zirconia enriched glass fiber composite posts (Ice Light, Danville, USA) were cemented in the roots using a dual-cure resin cement (Panavia F 2.0, Kuraray, Japan) according to the manufacturer’s instructions. The teeth were restored with composite resin cores (Lumiglass, RTD, France) using a prefabricated polyester matrix. After periodontal ligament (PDL) simulation by elastic polyether impression material (Impregum, 3M ESPE, USA), specimens were mounted in acrylic resin and subjected to 1195 Instron universal testing machine. Compressive load was applied at a 90° angle relative to the long axis of the teeth at a crosshead speed of 1mm/min  until fracture. Since the data were normally distributed, t-test was used for statistical analysis.Results: The fracture resistance was 816.69 (120.89) N for zirconia posts and 843.76 (120.93) N for zirconia enriched glass fiber composite posts and these values were not significantly different (p=0.62). Fractures in group 2 were restorable.Conclusion: The fracture resistance of zirconia and zirconia enriched glass fiber composite posts was not significantly different and both types of posts can be successfully used

    Fuchs Heterochromic Iridocyclitis-Associated Glaucoma: A Retrospective Comparison of Primary Ahmed Glaucoma Valve implantation and Trabeculectomy with MMC

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    Purpose: To compare the safety and efficacy of a primary trabeculectomy with mitomycin C (T) and an Ahmed glaucoma valve (AGV) implantation in patients with Fuchs heterochromic iridocyclitis (FHIC) related glaucoma, a rare complication of an uncommon form of uveitis. Design: Retrospective comparative case series. Method: Twenty-six patients with uncontrolled FHIC-associated glaucoma received T (n=12) or an AGV (n=14). Primary outcome measures were the surgical success defined as IOP ≀ 21 mmHg and decreased ≄ 20% from the baseline and no secondary glaucoma surgery. Secondary outcome measures were the number of glaucoma medications, complications, best corrected visual acuity (BCVA), and intraocular pressure. Results: The follow-up (mean±SD) was 34.0±17.7 in T and 33.4±18.6 months in AGV (p = 0.837). The cumulative probability of success rate at the final follow-up at three years was 41.7% for T and 85.7% for AGV. There was no significant difference in complications between the two groups (P>0.05). The mean preoperative IOP in T was 23.4±3.3 mmHg and 21.6±5.2 mmHg at the final visit (P= 0.041). In AGV, the preoperative IOP was 24±7.8 and 17.1±2.6 mmHg at the final visit (P= 0.003), respectively. AGV had a significantly lower average IOP at the final follow-up visit compared to T (P= 0.018). The number of glaucoma medications at baseline was 3.3±0.5 in T and 3±0.6 in AGV (P= 0.233). This decreased significantly to 2.4±1.0 and 1.7±0.6 at the final follow-up (P= 0.008 and 0.002, respectively). Patients in AGV needed fewer glaucoma medications (P= 0.041). BCVA was equal in both groups and did not change (p>0.05). Conclusion: Primary AGV had a higher success rate than T in the management of FHIC-associated glaucoma. The risk of cataract formation and progression was significantly higher following T in these patients

    A novel onset detection technique for brain?computer interfaces using sound-production related cognitive tasks in simulated-online system

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    Objective. Self-paced EEG-based BCIs (SP-BCIs) have traditionally been avoided due to two sources of uncertainty: (1) precisely when an intentional command is sent by the brain, i.e., the command onset detection problem, and (2) how different the intentional command is when compared to non-specific (or idle) states. Performance evaluation is also a problem and there are no suitable standard metrics available. In this paper we attempted to tackle these issues. Approach. Self-paced covert sound-production cognitive tasks (i.e., high pitch and siren-like sounds) were used to distinguish between intentional commands (IC) and idle states. The IC states were chosen for their ease of execution and negligible overlap with common cognitive states. Band power and a digital wavelet transform were used for feature extraction, and the Davies?Bouldin index was used for feature selection. Classification was performed using linear discriminant analysis. Main results. Performance was evaluated under offline and simulated-online conditions. For the latter, a performance score called true-false-positive (TFP) rate, ranging from 0 (poor) to 100 (perfect), was created to take into account both classification performance and onset timing errors. Averaging the results from the best performing IC task for all seven participants, an 77.7% true-positive (TP) rate was achieved in offline testing. For simulated-online analysis the best IC average TFP score was 76.67% (87.61% TP rate, 4.05% false-positive rate). Significance. Results were promising when compared to previous IC onset detection studies using motor imagery, in which best TP rates were reported as 72.0% and 79.7%, and which, crucially, did not take timing errors into account. Moreover, based on our literature review, there is no previous covert sound-production onset detection system for spBCIs. Results showed that the proposed onset detection technique and TFP performance metric have good potential for use in SP-BCIs

    Functional Folate Receptor Alpha Is Elevated in the Blood of Ovarian Cancer Patients

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    Background Despite low incidence, ovarian cancer is the fifth leading cause of cancer deaths and it has the highest mortality rate of all gynecologic malignancies among US women. The mortality rate would be reduced with an early detection marker. The folate receptor alpha (FRα) is one logical choice for a biomarker because of its prevalent overexpression in ovarian cancer and its exclusive expression in only a few normal tissues. In prior work, it was observed that patients with ovarian cancer had elevated serum levels of a protein that bound to a FRα-specific monoclonal antibody relative to healthy individuals. However, it was not shown that the protein detected was intact functional FRα. In the current study, the goal was to determine whether ovarian cancer patients (n = 30) had elevated serum levels of a fully functional intact FRα compared to matched healthy controls (n = 30). Methodology/Principal Findings FRα levels in serum were analyzed by two methods, immunoblotting analysis and a radiolabeled folic acid-based microfiltration binding assay. Using the immunoassay, we observed that levels of FRα were higher in serum of ovarian cancer patients as compared to controls. Similar results were also observed using the microfiltration binding assay, which showed that the circulating FRα is functional. Importantly, we also found that the levels of FRα were comparable between early and advanced stage patients. Conclusions Our results demonstrate that ovarian cancer patients have elevated levels of functional intact FRα. These findings support the potential use of circulating FRα as a biomarker of early ovarian cancer

    Ultrasonographic Characteristics of Subacute Granulomatous Thyroiditis

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    Objective: We wanted to describe the characteristic ultrasonography (US) features and clinical findings for making the diagnosis of subacute granulomatous thyroiditis. Materials and Methods: A total of 31 lesions from 27 patients were confirmed as subacute granulomatous thyroiditis by US-guided fine needle aspiration biopsy. We analyzed the ultrasonographic findings such as the lesion's size, margin and shape, the discrepancy between length and breadth and the vascularity. The clinical findings such as acute neck pain or fever were reviewed. The follow-up clinical and ultrasonographic data were reviewed for 15 patients. Results: The thyroid gland was found to be enlarged in five patients, it was normal size in 20 patients and it was smaller in two patients. All the lesions had focally ill-defined hypoechogenicity. Hypervascularity was not noted in any of the lesions. Painful neck swelling was present in 18 patients. An accompanying fever was documented in nine of the 18 patients. Twelve patients showed disappearance (n = 3) or a decreased size (n = 9) of their lesions on follow-up US. Conclusion: The presence of ill-defined hypoechoic thyroid lesions without a discrete round or oval shape is characteristic for subacute granulomatous thyroiditis, and particularly when this is associated with painful neck swelling and/or fever.ope

    Fuchs heterochromic iridocyclitis-associated glaucoma: a retrospective comparison of primary Ahmed glaucoma valve implantation and trabeculectomy with mitomycin C [version 2; referees: 2 approved]

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    Background: The aim of this study was to compare the safety and efficacy of primary trabeculectomy with mitomycin C and Ahmed glaucoma valve (AGV) implantation in patients with Fuchs heterochromic iridocyclitis (FHIC)-related glaucoma, a rare complication of an uncommon form of uveitis. Methods: In this retrospective comparative case series, 26 FHIC-associated glaucoma patients received trabeculectomy (n=12) or an AGV (n=14). Primary outcome measures were surgical success, defined as intraocular pressure (IOP) ≀21 mmHg, decreasing ≄20% from baseline, and no secondary glaucoma surgery. Secondary outcome measures were the number of glaucoma medications, complications, best corrected visual acuity (BCVA), and IOP. Results: The follow-up was 34.0±17.7 months in patients that received trabeculectomy and 33.4±18.6 months in AGV (P= 0.837). The cumulative probability of success rate was 41.7% for trabeculectomy and 85.7% for AGV, with no significant difference in complications (P>0.05). The IOP in patients that received trabeculectomy dropped from 23.4±3.3 mmHg to 21.6±5.2 mmHg at the final visit (P= 0.041). In patients that received AGV, the IOP decreased from 24±7.8 to 17.1±2.6 mmHg (P= 0.003). The number of glaucoma medications at baseline were 3.3±0.5 in those that received trabeculectomy and 3±0.6 in those that received AGV (P=0.233), and decreased to 2.4±1.0 (P=0.008) and 1.7±0.6 (P=0.002), respectively. BCVA was equal in both groups and did not change (P>0.05). Conclusion: Primary AGV had a higher success rate than trabeculectomy, with patients also needing fewer medications for the management of FHIC-associated glaucoma

    A Generic Transferable EEG Decoder for Online Detection of Error Potential in Target Selection

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    Reliable detection of error from electroencephalography (EEG) signals as feedback while performing a discrete target selection task across sessions and subjects has a huge scope in real-time rehabilitative application of Brain-computer Interfacing (BCI). Error Related Potentials (ErrP) are EEG signals which occur when the participant observes an erroneous feedback from the system. ErrP holds significance in such closed-loop system, as BCI is prone to error and we need an effective method of systematic error detection as feedback for correction. In this paper, we have proposed a novel scheme for online detection of error feedback directly from the EEG signal in a transferable environment (i.e., across sessions and across subjects). For this purpose, we have used a P300-speller dataset available on a BCI competition website. The task involves the subject to select a letter of a word which is followed by a feedback period. The feedback period displays the letter selected and, if the selection is wrong, the subject perceives it by the generation of ErrP signal. Our proposed system is designed to detect ErrP present in the EEG from new independent datasets, not involved in its training. Thus, the decoder is trained using EEG features of 16 subjects for single-trial classification and tested on 10 independent subjects. The decoder designed for this task is an ensemble of linear discriminant analysis, quadratic discriminant analysis, and logistic regression classifier. The performance of the decoder is evaluated using accuracy, F1-score, and Area Under the Curve metric and the results obtained is 73.97, 83.53, and 73.18%, respectively

    Full Mouth Rehabilitation with Implant-Supported Prostheses for Severe Periodontitis: A Case Report

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    Oral rehabilitation for a patient with severe loss of alveolar bone and soft tissue resulting from severe periodontitis presents a challenge to clinicians. Replacing loosening natural teeth with fixed prostheses supported by dental implants often requires either gingival surgery or bone grafting. The outcome of the bone grafting is sometimes unpredictable and requires longer healing time and/ or multiple surgeries. The presence of periodontal inflammation and periapical lesions often delay the placement of bone grafts as well as dental implants. Here we present a clinical case of a patient undergone full mouth reconstruction with implant-supported fixed prostheses. We demonstrated that early placement of implants (three weeks after extractions) with minimal bone grafting may be an alternative to conventional bone grafting followed by implant placement. We believe that primary stability during implant placement may contribute to our success. In addition, composite resin gingival material may be indicated in cases of large fixed implant prostheses as an alternative to pink porcelain
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