573 research outputs found
Leveraging Self-Supervised Vision Transformers for Neural Transfer Function Design
In volume rendering, transfer functions are used to classify structures of
interest, and to assign optical properties such as color and opacity. They are
commonly defined as 1D or 2D functions that map simple features to these
optical properties. As the process of designing a transfer function is
typically tedious and unintuitive, several approaches have been proposed for
their interactive specification. In this paper, we present a novel method to
define transfer functions for volume rendering by leveraging the feature
extraction capabilities of self-supervised pre-trained vision transformers. To
design a transfer function, users simply select the structures of interest in a
slice viewer, and our method automatically selects similar structures based on
the high-level features extracted by the neural network. Contrary to previous
learning-based transfer function approaches, our method does not require
training of models and allows for quick inference, enabling an interactive
exploration of the volume data. Our approach reduces the amount of necessary
annotations by interactively informing the user about the current
classification, so they can focus on annotating the structures of interest that
still require annotation. In practice, this allows users to design transfer
functions within seconds, instead of minutes. We compare our method to existing
learning-based approaches in terms of annotation and compute time, as well as
with respect to segmentation accuracy. Our accompanying video showcases the
interactivity and effectiveness of our method
Spatially Guiding Unsupervised Semantic Segmentation Through Depth-Informed Feature Distillation and Sampling
Traditionally, training neural networks to perform semantic segmentation
required expensive human-made annotations. But more recently, advances in the
field of unsupervised learning have made significant progress on this issue and
towards closing the gap to supervised algorithms. To achieve this, semantic
knowledge is distilled by learning to correlate randomly sampled features from
images across an entire dataset. In this work, we build upon these advances by
incorporating information about the structure of the scene into the training
process through the use of depth information. We achieve this by (1) learning
depth-feature correlation by spatially correlate the feature maps with the
depth maps to induce knowledge about the structure of the scene and (2)
implementing farthest-point sampling to more effectively select relevant
features by utilizing 3D sampling techniques on depth information of the scene.
Finally, we demonstrate the effectiveness of our technical contributions
through extensive experimentation and present significant improvements in
performance across multiple benchmark datasets
Neurocognitive deficits in depression: a systematic review of cognitive impairment in the acute and remitted state
Previous research suggests a broad range of deficits in major depressive disorder. Our goal was to update the current assumptions and investigate the extent of cognitive impairment in depression in the acute and remitted state. A systematic review of the existing literature between 2009 and 2019 assessing the risk of bias within the included studies was performed. Of the 42 articles reviewed, an unclear risk of bias was shown overall. The risk of bias mainly concerned the sample selection, inadequate remedial measures, as well as the lack of blinding the assessors. In the acute phase, we found strong support for impairment in processing speed, learning, and memory. Follow-up studies and direct comparisons revealed less pronounced deficits in remission, however, deficits were still present in attention, learning and memory, and working memory. A positive correlation between the number of episodes and cognitive deficits as well as depression severity and cognitive deficits was reported. The results also demonstrate a resemblance between the cognitive profiles in bipolar disorder and depression. Comparisons of depression with schizophrenia led to unclear results, at times suggesting an overlap in cognitive performance. The main findings support the global deficit hypothesis and align with results from prior meta-analyses and reviews. Recommendations for future research are also presented
Testing the accuracy of feldspar single grains to date late Holocene cyclone and tsunami deposits
Quartz is the preferred dosimeter for luminescence dating of Holocene sediments as optically stimulated luminescence (OSL) signals reset rapidly upon light exposure, and are stable over time. However, feldspar is required where quartz luminescence properties are inappropriate for dating, as is often the case in geologically young mountain ranges and areas with young volcanism. Here we aim to evaluate the potential of single grain feldspar luminescence dating applied to late Holocene cyclone and tsunami deposits, for which complete signal resetting can a priori not be guaranteed. To address potential problems of feldspar dating of such deposits associated with heterogeneous bleaching, remnant doses and anomalous fading, we use a low-temperature post infrared infrared stimulated luminescence protocol (pIRIR150) on single grains. For most samples, good agreement between fading corrected IR50 and non-fading corrected pIRIR150 ages is observed. Both feldspar ages generally also show good agreement with age control provided by historical data and quartz luminescence ages. pIRIR150 remnant ages in modern analogue samples are shown to be 150, IR50 and quartz ages, indicates that a significant number of grains must have experienced relatively complete signal resetting during or immediately prior to transport, as the three signals are known to bleach at different rates. Since light exposure during the event is expected to be limited, we deduce that a significant portion of the grains in the cyclone and tsunami deposits was already bleached prior to the event of interest. These well-bleached grains were likely eroded at the beach, while other grains with larger remnant ages probably originate from the shallow subtidal, coastal barriers or even further inland sources. Additional signal resetting during storm and tsunami transport is indicated by slightly younger quartz than feldspar ages for grains with incomplete pre-transport resetting that were eroded at the Holocene coastal barrier.</p
Free-Flap Reconstruction in Early-Stage Squamous Cell Carcinoma of the Oral Cavity : A Prospective Monocentric Trial to Evaluate Oncological Outcome and Quality of Life
Surgery is generally accepted as standard treatment in oral cancer, but the reconstructive
procedures remain a matter of debate. The aim of this study was to evaluate oncological outcome
and quality of life following surgical resection and free-flap reconstruction in patients with early oral
squamous cell carcinoma. The presented trial was performed as a prospective, single-center observation study. Inclusion criteria were primary surgery in early-stage oral squamous cell carcinoma
with free-flap reconstruction. Endpoints were overall and progression-free survival and quality of
life up to 24 months after surgery. Twenty-six patients were included. Overall survival was 100%
and progression-free survival was 92.3% in a maximum follow-up time of 21 months. Global quality
of life showed no significant alteration after surgery. Patients reported a significant reduction in
pain (p = 0.048) and a decreasing impairment of speech one year after surgery (p = 0.021). Free-flap
reconstruction is a safe procedure that results in excellent oncological outcome and quality of life.
Functional outcome is of high relevance in early-stage tumors of the head and neck and may mostly
be affected by reconstructive procedures. Therefore, a prospective evaluation to explore success and
the effects of surgical therapy is highly warranted
Finding Nano-\"Otzi: Semi-Supervised Volume Visualization for Cryo-Electron Tomography
Cryo-Electron Tomography (cryo-ET) is a new 3D imaging technique with
unprecedented potential for resolving submicron structural detail. Existing
volume visualization methods, however, cannot cope with its very low
signal-to-noise ratio. In order to design more powerful transfer functions, we
propose to leverage soft segmentation as an explicit component of visualization
for noisy volumes. Our technical realization is based on semi-supervised
learning where we combine the advantages of two segmentation algorithms. A
first weak segmentation algorithm provides good results for propagating sparse
user provided labels to other voxels in the same volume. This weak segmentation
algorithm is used to generate dense pseudo labels. A second powerful
deep-learning based segmentation algorithm can learn from these pseudo labels
to generalize the segmentation to other unseen volumes, a task that the weak
segmentation algorithm fails at completely. The proposed volume visualization
uses the deep-learning based segmentation as a component for segmentation-aware
transfer function design. Appropriate ramp parameters can be suggested
automatically through histogram analysis. Finally, our visualization uses
gradient-free ambient occlusion shading to further suppress visual presence of
noise, and to give structural detail desired prominence. The cryo-ET data
studied throughout our technical experiments is based on the highest-quality
tilted series of intact SARS-CoV-2 virions. Our technique shows the high impact
in target sciences for visual data analysis of very noisy volumes that cannot
be visualized with existing techniques
Neurocognitive Deficits in First-Episode and Chronic Psychotic Disorders: A Systematic Review from 2009 to 2022
Cognitive impairment in patients suffering from schizophrenia spectrum disorders has been discussed as a strong predictor for multiple disease outcome variables, such as response to psychotherapy, stable relationships, employment, and longevity. However, the consistency and severity of cognitive deficits across multiple domains in individuals with first-episode and chronic psychotic disorders is still undetermined. We provide a comprehensive overview of primary research from the years 2009 to 2022. Based on a Cochrane risk assessment, a systematic synthesis of 51 out of 3669 original studies was performed. Impairment of cognitive functioning in patients diagnosed with first-episode psychotic disorders compared with healthy controls was predicted to occur in all assessed cognitive domains. Few overall changes were predicted for chronically affected patients relative to those in the first-episode stage, in line with previous longitudinal studies. Our research outcomes support the hypothesis of a global decrease in cognitive functioning in patients diagnosed with psychotic disorders, i.e., the occurrence of cognitive deficits in multiple cognitive domains including executive functioning, memory, working memory, psychomotor speed, and attention. Only mild increases in the frequency of cognitive impairment across studies were observed at the chronically affected stage relative to the first-episode stage. Our results confirm and extend the outcomes from prior reviews and meta-analyses. Recommendations for psychotherapeutic interventions are provided, considering the broad cognitive impairment already observed at the stage of the first episode. Based on the risk of bias assessment, we also make specific suggestions concerning the quality of future original studies
Surgical Treatment of Carcinomas of the Oral Minor Salivary Glands : Oncological Outcome in Dependence of Tumor Entity and Therapeutic Strategies
The aim of this study was to analyze the clinical outcomes of three types of minor salivary
gland carcinomas (adenoid-cystic carcinomas (ACC), adeno carcinomas not otherwise specified
(AC-NOS), and mucoepidermoid carcinomas (MEC)) after primary surgical therapy. A retrospective
cohort study was designed and patients with cancer of the minor oral salivary glands treated in our
department in the years 2011 to 2022 were included. Clinicopathological data were evaluated to
compare overall survival and progression-free survival between the entities. Eighty-one patients were
included. The rates of cervical metastases were 38.9% for ACC, 25% for MEC, and 9.1% for AC-NOS.
ACC exhibited significantly higher rates of local and systemic disease recurrence (p = 0.02), and the
presence of neck node metastases was confirmed as an independent prognostic factor for progressionfree survival (p = 0.014). Treatment success in terms of oncological outcome varied significantly
between the different entities and implies different treatment regimens for each tumor entity
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