61 research outputs found

    Thumb function and appearance following treatment of Wassel type III duplication thumbs

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    AbstractObjectiveThe purpose of our study is to evaluate thumb function and appearance after surgical correction of Wassel type III thumbs polydactyly.MethodsWe have reconstructed 28 cases of Wassel type III duplication thumbs, in which the duplicated digits were equal or almost equal in size by ablation of a radial digit. The extra thumb is osteotomized at the bifurcation level and excised except for the distal bone fragment supporting the nail bed and fillet flap. Meanwhile, the nail of the retained thumb should be reserved completely, and if the nail has relatively poor appearance it should be repaired by nail lengthening surgery. Eighteen cases were followed up for more than 3 years and were available for assessment using the Japanese Society for Surgery of the Hand evaluation form. The average age at follow-up was 5 years. The size of the nail and distal phalanx was measured to assess the growth of the thumb.ResultsAn average functional point was 12 points (maximum 14 points) and the cosmetic score averaged 3.6 (maximum 4 points) after the assessment. Slightly small nails without a central ridge were deemed acceptable. Second revision surgery is seldom. Long-term results after surgical reconstruction for duplication thumbs were excellent, and all patients and parents were satisfied with the cosmetic and functional results.ConclusionsThis procedure is a helpful and effective way to provide functional and aesthetical thumb for Wassel type III duplication thumbs

    Echo Planar Time-Resolved Imaging (EPTI) with Subspace Reconstruction and Optimized Spatiotemporal Encoding

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    Purpose: To develop new encoding and reconstruction techniques for fast multi-contrast quantitative imaging. Methods: The recently proposed Echo Planar Time-resolved Imaging (EPTI) technique can achieve fast distortion- and blurring-free multi-contrast quantitative imaging. In this work, a subspace reconstruction framework is developed to improve the reconstruction accuracy of EPTI at high encoding accelerations. The number of unknowns in the reconstruction is significantly reduced by modeling the temporal signal evolutions using low-rank subspace. As part of the proposed reconstruction approach, a B0-update algorithm and a shot-to-shot B0 variation correction method are developed to enable the reconstruction of high-resolution tissue phase images and to mitigate artifacts from shot-to-shot phase variations. Moreover, the EPTI concept is extended to 3D k-space for 3D GE-EPTI, where a new temporal-variant of CAIPI encoding is proposed to further improve performance. Results: The effectiveness of the proposed subspace reconstruction was demonstrated first in 2D GESE EPTI, where the reconstruction achieved higher accuracy when compared to conventional B0-informed GRAPPA. For 3D GE-EPTI, a retrospective undersampling experiment demonstrates that the new temporal-variant CAIPI encoding can achieve up to 72x acceleration with close to 2x reduction in reconstruction error when compared to conventional spatiotemporal-CAIPI encoding. In a prospective undersampling experiment, high-quality whole-brain T2* and QSM maps at 1 mm isotropic resolution was acquired in 52 seconds at 3T using 3D GE-EPTI with temporal-variant CAIPI encoding. Conclusion: The proposed subspace reconstruction and optimized temporal-variant CAIPI encoding can further improve the performance of EPTI for fast quantitative mapping

    Phylogenetic structure and formation mechanism of shrub communities in arid and semiarid areas of the Mongolian Plateau

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    The mechanisms of species coexistence within a community have always been the focus in ecological research. Community phylogenetic structure reflects the relationship of historical processes, regional environments, and interactions between species, and studying it is imperative to understand the formation and maintenance mechanisms of community composition and biodiversity. We studied the phylogenetic structure of the shrub communities in arid and semiarid areas of the Mongolian Plateau. First, the phylogenetic signals of four plant traits (height, canopy, leaf length, and leaf width) of shrubs and subshrubs were measured to determine the phylogenetic conservation of these traits. Then, the net relatedness index (NRI) of shrub communities was calculated to characterize their phylogenetic structure. Finally, the relationship between the NRI and current climate and paleoclimate (since the Last Glacial Maximum, LGM) factors was analyzed to understand the formation and maintenance mechanisms of these plant communities. We found that desert shrub communities showed a trend toward phylogenetic overdispersion; that is, limiting similarity was predominant in arid and semiarid areas of the Mongolian Plateau despite the phylogenetic structure and formation mechanisms differing across habitats. The typical desert and sandy shrub communities showed a significant phylogenetic overdispersion, while the steppified desert shrub communities showed a weak phylogenetic clustering. It was found that mean winter temperature (i.e., in the driest quarter) was the major factor limiting steppified desert shrub phylogeny distribution. Both cold and drought (despite having opposite consequences) differentiated the typical desert to steppified desert shrub communities. The increase in temperature since the LGM is conducive to the invasion of shrub plants into steppe grassland, and this process may be intensified by global warming

    Bibliometric and visual analysis of spinal cord injury-associated macrophages from 2002 to 2023

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    BackgroundSpinal cord injury (SCI) triggers motor, sensory, and autonomic impairments that adversely damage patients' quality of life. Its pathophysiological processes include inflammation, oxidative stress, and apoptosis, although existing treatment options have little success. Macrophages have a vital function in controlling inflammation in SCI, with their M1-type and M2-type macrophages dominating early inflammatory effects and late brain tissue repair and regeneration, respectively. However, there is a dearth of rigorous bibliometric study in this sector to explore its dynamics and trends. This study intends to examine the current status and trends of macrophage usage in SCI using bibliometric methodologies, which may drive novel therapeutic options.MethodsIn this study, the Web of Science Core Collection (WOSCC) was utilized to collect publications and reviews on macrophages in SCI from 2002 to 2023. Bibliometrics and visualization analyses were performed by VOSviewer, CiteSpace, the R package “bibliometrix”, and online analytic platforms. These analyses covered a variety of aspects, including countries and institutions, authors and co-cited authors, journals and co-cited journals, subject categories, co-cited references, and keyword co-occurrences, in order to provide insights into the research trends and hotspots in this field.Results1,775 papers were included in the study, comprising 1,528 articles and 247 reviews. Our research analysis demonstrates that the number of relevant studies in this sector is expanding, specifically the number of publications in the United States and China has risen dramatically. However, there are fewer collaborations between institutions in different nations, and international cooperation needs to be reinforced. Among them, Popovich PG became the leader in the field, and significant journals include Experimental Neurology, Journal of Neurotrauma, and Journal of Neuroscience. Research hotspots involve macrophage polarization, microglia, astrocytes, signaling, cytokines, inflammation, and neuroprotection.ConclusionsThis analysis gives, for the first time, a comprehensive overview of bibliometric studies on macrophages in SCI over the past 20 years. This study not only gives an extensive picture of the knowledge structure but also indicates trends in the subject. The systematic summarization gives a complete and intuitive understanding of the link between spinal cord damage and macrophages and provides a great reference for future related studies

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    MRI techniques for quantitative and microstructure imaging

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    The ability to map brain microstructures such as axonal fibers and myelin content is critical in improving our understanding of brain organization and neurological diseases. Quantitative MRI has been proved with its high sensitivity to microstructures, providing a safe, non-invasive approach for human in vivo imaging. However, quantitative MRI typically requires the acquisition of multiple images for biophysical model fitting, which leads to long scan time that consequently causes low SNR, low spatial resolution, image artifacts and vulnerability to motion. This thesis aims at overcoming these challenges by developing novel MRI acquisition and reconstruction methods that exploit the strength of spatiotemporal encoding, recent hardware innovations and low-rank signal priors, to provide efficient microstructure imaging of the human brain with higher speed, SNR, resolution, and motion robustness. Three quantitative MRI contrasts were studied in this thesis, including diffusion MRI, myelin water imaging, and MR relaxometry. These contrasts provide sensitivity to axonal fibers, myelin concentration, and iron contents for the study of brain microstructures. Specifically, in the first part of this thesis, a fast and high-fidelity diffusion imaging method was developed that achieves 30-40% higher SNR-efficiency than the current state-of-the-art method. This technique was also shown to be robust to physiological motion and field variations, as well as the capability to resolve multi-echo images that are free from image distortions and artifacts. The second part of this thesis presents a novel acquisition method for myelin water imaging with >10× acceleration compared to current approaches, that can potentially be used for a fast examination of demyelination diseases. The work also demonstrates the first submillimeter myelin water imaging in vivo at 600-um isotropic resolution to study cortical myeloarchitecture. The third part of this thesis shows an ultra-fast MR relaxometry method with navigated motion correction, which provides fast, repeatable, and motion-robust quantitative imaging of the human brain.Ph.D

    Motion parameters estimation of manoeuvring weak target with multiple motion stages based on range symmetry transform and short‐time fractional Fourier transform

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    Abstract With the advancement of manoeuvrability and the increasement of coherent processing interval (CPI), the observed target might be of multiple motion stages. Therefore, most existing long‐time coherent integration (LTCI) algorithms based on the assumption of single‐motion stage is not proper any more. To address this problem, this letter proposes an effective motion parameters estimation algorithm, which is the key step of LTCI, for the manoeuvring weak target with multiple motion stages based on range symmetry transform and short‐time fractional Fourier transform (RST‐STFrFT). The effectiveness of the proposed algorithm is verified by signal‐level simulations
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