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Heliyon Nov 2023This study examined the differences in the pausing behavior between native and non-native English speakers. Specifically, it examined the location and duration of pauses...
This study examined the differences in the pausing behavior between native and non-native English speakers. Specifically, it examined the location and duration of pauses in relation to the syntactic and lexical complexity of the clauses in which these pauses occur and the nature of the prosodic phrasing of the utterances containing pauses. Speech samples from 10 native (L1) English and 10 Mandarin non-native English speakers from the Archive of L1 and L2 Scripted and Spontaneous Transcripts and Recordings (ALLSSTAR) were included in the analysis. The results showed that lower-level prosodic boundaries and syntactically complex phrases were associated with significantly longer pause duration in the L2 speech. Additionally, phrases with less frequent words tended to induce longer pauses. These findings suggest that insufficient knowledge of the L2 syntax, lexicon, and prosody might determine the location and duration of pauses and ultimately affect the speech fluency of L2 speakers.
PubMed: 37954378
DOI: 10.1016/j.heliyon.2023.e21322 -
Medical Image Computing and... 2021Spatial resolution plays a critically important role in MRI for the precise delineation of the imaged tissues. Unfortunately, acquisitions with high spatial resolution...
Spatial resolution plays a critically important role in MRI for the precise delineation of the imaged tissues. Unfortunately, acquisitions with high spatial resolution require increased imaging time, which increases the potential of subject motion, and suffers from reduced signal-to-noise ratio (SNR). Super-resolution reconstruction (SRR) has recently emerged as a technique that allows for a trade-off between high spatial resolution, high SNR, and short scan duration. Deconvolution-based SRR has recently received significant interest due to the convenience of using the image space. The most critical factor to succeed in deconvolution is the accuracy of the estimated blur kernels that characterize how the image was degraded in the acquisition process. Current methods use handcrafted filters, such as Gaussian filters, to approximate the blur kernels, and have achieved promising SRR results. As the image degradation is complex and varies with different sequences and scanners, handcrafted filters, unfortunately, do not necessarily ensure the success of the deconvolution. We sought to develop a technique that enables accurately estimating blur kernels from the image data itself. We designed a deep architecture that utilizes an adversarial scheme with a generative neural network against its degradation counterparts. This design allows for the SRR tailored to an individual subject, as the training requires the scan-specific data only, i.e., it does not require auxiliary datasets of high-quality images, which are practically challenging to obtain. With this technique, we achieved high-quality brain MRI at an isotropic resolution of 0.125 cubic mm with six minutes of imaging time. Extensive experiments on both simulated low-resolution data and clinical data acquired from ten pediatric patients demonstrated that our approach achieved superior SRR results as compared to state-of-the-art deconvolution-based methods, while in parallel, at substantially reduced imaging time in comparison to direct high-resolution acquisitions.
PubMed: 34713277
DOI: 10.1007/978-3-030-87231-1_42 -
EJNMMI Physics Mar 2021The amount of signal decreases when the acquisition duration is shortened. However, it is not clear how this affects the quantitative values. This study aims to clarify...
BACKGROUND
The amount of signal decreases when the acquisition duration is shortened. However, it is not clear how this affects the quantitative values. This study aims to clarify the effect of acquisition time shortening in brain tumor PET/CT using C-methionine on the quantitative values.
METHOD
This study was a retrospective analysis of 30 patients who underwent clinical C-methionine PET/CT examination. PET images were acquired in list mode for 10 min. PET images of acquisition duration from 1 to 10 min with 1-min step were reconstructed. We examined the effect on the quantitative values of acquisition duration. We placed a volume of interest to include the entire tumor and regions of interest in the shape of a large crescent in the contralateral hemisphere in 5 contiguous axial slices as normal tissue. Quantitative values examined were maximum, peak, and mean standardized uptake values (SUVmax, SUVpeak, SUVmean), metabolic tumor volume (MTV), and maximum tumor to normal tissue ratio (TNRmax), with each duration compared to that with 10 min.
RESULTS
SUVmax, MTV, and TNRmax showed the highest values due to the effects of statistical noise when the acquisition time was 1 min. These values were stable when the acquisition duration was > 6 min. SUVpeak and SUVmean showed mostly consistent values regardless of duration.
CONCLUSIONS
SUVmax, MTV, and TNRmax are affected by acquisition time. If the acquisition duration was > 6 min, the fluctuation could be suppressed within 5% in these quantitative values. However, SUVpeak was suggested to be a robust index regardless of the acquisition duration.
PubMed: 33788057
DOI: 10.1186/s40658-021-00379-2 -
Journal of Nuclear Medicine Technology Dec 2017Continuous-bed-motion (CBM) acquisition mode has been made commercially available in PET/CT scanners. CBM mode is designed for whole-body imaging, with a long scan... (Comparative Study)
Comparative Study
Continuous-bed-motion (CBM) acquisition mode has been made commercially available in PET/CT scanners. CBM mode is designed for whole-body imaging, with a long scan length (multiple axial fields of view [aFOVs]) and short acquisition duration (2-3 min/aFOV). PET/CT has recently been used after Y-microsphere therapy to quantify Y activity distribution in the liver. Here we compared counting efficiencies along the bed-motion direction (-axis) between CBM and step-and-shoot (SS) acquisition modes for limited-view organ scans, such as Y PET/CT liver studies, that have short scan lengths (≤2 aFOVs) and long acquisition durations (10-30 min/aFOV). The counting efficiencies, that is, analytic sensitivities, in SS mode (single-aFOV and multiple-aFOV scans) and CBM mode were theoretically derived and experimentally validated using a cylindric Ge phantom. The sensitivities along the -axis were compared between the SS and CBM modes. The analytic and experimental count profiles were in good agreement, validating the analytic models. For fixed scan durations, the overall coincidence counting efficiency in CBM mode was lower (∼60%) than those in SS modes, and the maximum sensitivity in CBM mode was 50% or less of that in 1-aFOV SS mode and 100% or less of that in 2-aFOV SS mode. The ability of CBM mode to tailor-fit the PET/CT scan length and local scan duration is not realized in studies with a short scan length (≤30 cm) and long scan duration (20 min/aFOV for the scanner). SS acquisition mode is preferable to CBM mode for limited-view organ and count-starved scans, such as Y PET/CT liver scans, because of the higher counting efficiency of SS mode, which leads to better image quality and quantification precision.
Topics: Motion; Positron Emission Tomography Computed Tomography; Time Factors; Yttrium Radioisotopes
PubMed: 29042468
DOI: 10.2967/jnmt.117.195438 -
PloS One 2020The increasing interest in Virtual Reality (VR) as a tool for neuroscientific research contrasts with the current lack of established toolboxes and standards. In several...
The increasing interest in Virtual Reality (VR) as a tool for neuroscientific research contrasts with the current lack of established toolboxes and standards. In several recent studies, game engines like Unity or Unreal Engine were used. It remains to be tested whether these software packages provide sufficiently precise and accurate stimulus timing and time measurements that allow inferring ongoing mental and neural processes. We here investigated the precision and accuracy of the timing mechanisms of Unreal Engine 4 and SteamVR in combination with the HTC Vive VR system. In a first experiment, objective external measures revealed that stimulus durations were highly accurate. In contrast, in a second experiment, the assessment of the precision of built-in timing procedures revealed highly variable reaction time measurements and inaccurate determination of stimulus onsets. Hence, we developed a new software-based method that allows precise and accurate reaction time measurements with Unreal Engine and SteamVR. Instead of using the standard timing procedures implemented within Unreal Engine, time acquisition was outsourced to a background application. Timing benchmarks revealed that the newly developed method allows reaction time measurements with a precision and accuracy in the millisecond range. Overall, the present results indicate that the HTC Vive together with Unreal Engine and SteamVR can achieve high levels of precision and accuracy both concerning stimulus duration and critical time measurements. The latter can be achieved using a newly developed routine that allows not only accurate reaction time measures but also provides precise timing parameters that can be used in combination with time-sensitive functional measures such as electroencephalography (EEG) or transcranial magnetic stimulation (TMS).
Topics: Animals; Humans; Neurosciences; Photic Stimulation; Proof of Concept Study; Reaction Time; Time Factors; User-Computer Interface; Virtual Reality
PubMed: 32267886
DOI: 10.1371/journal.pone.0231152 -
Current Opinion in Microbiology Jun 2018Microbes often live in dense, dynamic, multi-species communities whose architecture and function are intimately intertwined. Imaging these complex, three-dimensional... (Review)
Review
Microbes often live in dense, dynamic, multi-species communities whose architecture and function are intimately intertwined. Imaging these complex, three-dimensional ensembles presents considerable technical challenges, however. In this review, I describe light sheet fluorescence microscopy, a technique that enables rapid acquisition of three-dimensional images over large fields of view and over long durations, and I highlight recent applications of this method to microbial systems that include artificial closed ecosystems, bacterial biofilms, and gut microbiota. I comment also on the history of light sheet imaging and the many variants of the method. Light sheet techniques have tremendous potential for illuminating the workings of microbial communities, a potential that is just beginning to be realized.
Topics: Biofilms; Gastrointestinal Microbiome; Imaging, Three-Dimensional; Light; Microbiota; Microscopy, Fluorescence
PubMed: 29175679
DOI: 10.1016/j.mib.2017.11.008 -
Journal of Neuroengineering and... Nov 2022A robotic rehabilitation gym can be defined as multiple patients training with multiple robots or passive sensorized devices in a group setting. Recent work with such...
BACKGROUND
A robotic rehabilitation gym can be defined as multiple patients training with multiple robots or passive sensorized devices in a group setting. Recent work with such gyms has shown positive rehabilitation outcomes; furthermore, such gyms allow a single therapist to supervise more than one patient, increasing cost-effectiveness. To allow more effective multipatient supervision in future robotic rehabilitation gyms, we propose an automated system that could dynamically assign patients to different robots within a session in order to optimize rehabilitation outcome.
METHODS
As a first step toward implementing a practical patient-robot assignment system, we present a simplified mathematical model of a robotic rehabilitation gym. Mixed-integer nonlinear programming algorithms are used to find effective assignment and training solutions for multiple evaluation scenarios involving different numbers of patients and robots (5 patients and 5 robots, 6 patients and 5 robots, 5 patients and 7 robots), different training durations (7 or 12 time steps) and different complexity levels (whether different patients have different skill acquisition curves, whether robots have exit times associated with them). In all cases, the goal is to maximize total skill gain across all patients and skills within a session.
RESULTS
Analyses of variance across different scenarios show that disjunctive and time-indexed optimization models significantly outperform two baseline schedules: staying on one robot throughout a session and switching robots halfway through a session. The disjunctive model results in higher skill gain than the time-indexed model in the given scenarios, and the optimization duration increases as the number of patients, robots and time steps increases. Additionally, we discuss how different model simplifications (e.g., perfectly known and predictable patient skill level) could be addressed in the future and how such software may eventually be used in practice.
CONCLUSIONS
Though it involves unrealistically simple scenarios, our study shows that intelligently moving patients between different rehabilitation robots can improve overall skill acquisition in a multi-patient multi-robot environment. While robotic rehabilitation gyms are not yet commonplace in clinical practice, prototypes of them already exist, and our study presents a way to use intelligent decision support to potentially enable more efficient delivery of technologically aided rehabilitation.
Topics: Humans; Robotics; Robotic Surgical Procedures; Computer Simulation; Exercise
PubMed: 36384813
DOI: 10.1186/s12984-022-01105-4 -
Journal of Nuclear Medicine Technology Jun 2021F-NaF PET/CT has a rapid single-pass extraction and fast clearance from soft tissues, resulting in a good target-to-background ratio. This study aimed to establish the... (Review)
Review
F-NaF PET/CT has a rapid single-pass extraction and fast clearance from soft tissues, resulting in a good target-to-background ratio. This study aimed to establish the optimum acquisition time and dosimetry for F-NaF PET/CT to evaluate bone metastases in obese patients. A secondary objective was to evaluate the impact of acquisition time on image quality, lesion detection rate, noise level, and radiation burden in this patient group. In total, 60 patients were included in the study (20 patients with a body mass index (BMI) of 30.0-34.9 kg/m, 20 with a BMI of 35-39.9 kg/m, and 20 with a BMI of >40 kg/m). Images were acquired after intravenous injection of a 2.2 MBq/kg (0.06 mCi/kg) dose of F-NaF. Data were acquired in list mode using ordered-subset expectation maximization reconstruction. The raw data were rebinned to simulate scans with acquisition times of 2, 2.5, and 3 min per bed position. The scans were visually analyzed by 2 observers and scored by rank against a panel of parameters (overall image quality, noise level, background soft tissue, and lesion detectability), and the contrast-to-noise ratio (CNR) was calculated. The mean CNR was 20.19 ± 8.39 for a 2-min acquisition, 21.03 ± 8.35 for 2.5 min, and 22.16 ± 8.37 for 3 min. There were no statistically significant differences in CNR among the 3 different acquisition durations ( > 0.05). Lesion delineation was excellent and independent of the acquisition time. All relevant lesions could be identified with all 3 acquisition times. A mean activity of 215.4 ± 31.3 MBq was injected, with estimated mean effective absorbed doses of 4.09 ± 0.59 mSv for F-NaF PET and 7.88 ± 1.66 mSv for CT alone. F-NaF PET/CT can be beneficial in obese patients because of its good pharmacokinetics. Optimal osseous staging can be achieved with relatively low doses and radiation burden. Lesion delineation was excellent regardless of acquisition time. However, it is recommended that an acquisition of 3 min per bed position be used in patients with a BMI of more than 40.
Topics: Humans; Lutetium; Obesity; Positron Emission Tomography Computed Tomography; Radiometry; Yttrium
PubMed: 33380519
DOI: 10.2967/jnmt.120.258137 -
The American Journal of Managed Care Feb 2001To compare factors that influence cost of antidepressant therapy between older tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) and... (Review)
Review
OBJECTIVE
To compare factors that influence cost of antidepressant therapy between older tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) and among drugs in the SSRI class.
STUDY DESIGN
Literature review.
RESULTS
Pharmacoeconomic data from the primary care and managed care settings demonstrate that the higher acquisition cost of the SSRIs is offset by reduced medical utilization because of a lower incidence of treatment-related adverse events, drug switching, and dosage adjustments than among patients taking TCAs. Analysis of pharmacy claims data suggests that drug acquisition costs, use of concomitant medications, incidence of dose titration, frequency of multitablet therapy (dose stratification), and duration of therapy are the key factors in determining the cost of SSRI therapy. Among the established SSRIs, drug acquisition costs are lowest for paroxetine and sertraline. Costs for concomitant medications may vary by healthcare plan. Recent reports indicate that paroxetine is associated with a low incidence of dose titration. Paroxetine and sertraline are available in extended dosage forms to reduce the need for multitablet therapy. Duration of therapy with all SSRIs is typically shorter than recommended.
CONCLUSION
Antidepressant therapy with SSRIs has been shown to be more cost effective than treatment with TCAs when overall healthcare utilization and expenses are considered.
Topics: Antidepressive Agents; Cost-Benefit Analysis; Depressive Disorder; Drug Costs; Humans; Selective Serotonin Reuptake Inhibitors; United States
PubMed: 11216334
DOI: No ID Found -
European Urology Jul 2015Partial nephrectomy (PN) is the current gold standard treatment for small localized renal tumors.; however, the impact of duration and type of intraoperative ischemia on... (Review)
Review
CONTEXT
Partial nephrectomy (PN) is the current gold standard treatment for small localized renal tumors.; however, the impact of duration and type of intraoperative ischemia on renal function (RF) after PN is a subject of significant debate.
OBJECTIVE
To review the current evidence on the relationship of intraoperative ischemia and RF after PN.
EVIDENCE ACQUISITION
A review of English-language publications on renal ischemia and RF after PN was performed from 2005 to 2014 using the Medline, Embase, and Web of Science databases. Ninety-one articles were selected with the consensus of all authors and analyzed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria.
EVIDENCE SYNTHESIS
The vast majority of reviewed studies were retrospective, nonrandomized observations. Based on the current literature, RF recovery after PN is strongly associated with preoperative RF and the amount of healthy kidney parenchyma preserved. Warm ischemia time (WIT) is modifiable and prolonged warm ischemia is significantly associated with adverse postoperative RF. Available data suggest a benefit of keeping WIT <25min, although the level of evidence to support this threshold is limited. Cold ischemia safely facilitates longer durations of ischemia. Surgical techniques that minimize or avoid global ischemia may be associated with improved RF outcomes.
CONCLUSIONS
Although RF recovery after PN is strongly associated with quality and quantity of preserved kidney, efforts should be made to limit prolonged WIT. Cold ischemia should be preferred when longer ischemia is expected, especially in presence of imperative indications for PN. Additional research with higher levels of evidence is needed to clarify the optimal use of renal ischemia during PN.
PATIENT SUMMARY
In this review of the literature, we looked at predictors of renal function after surgical resection of renal tumors. There is a strong association between the quality and quantity of renal tissue that is preserved after surgery and long-term renal function. The time of interruption of renal blood flow during surgery is an important, modifiable predictor of postoperative renal function.
Topics: Carcinoma, Renal Cell; Cold Ischemia; Humans; Kidney Neoplasms; Nephrectomy; Nephrons; Organ Sparing Treatments; Postoperative Complications; Renal Insufficiency; Warm Ischemia
PubMed: 25703575
DOI: 10.1016/j.eururo.2015.01.025