An official website of the United States government
BackgroundA lack of in utero imaging data hampers our understanding of the connections in the human fetal brain. Generalizing observations from postmortem subjects and premature newborns is inaccurate due to technical and biological differences. PurposeTo evaluate changes in fetal brain structural connectivity between 23 and 35 weeks postconceptional age using a spatiotemporal atlas of diffusion tensor imaging (DTI). Study TypeRetrospective. PopulationPublicly available diffusion atlases, based on 60 healthy women (age 18–45 years) with normal prenatal care, from 23 and 35 weeks of gestation. Field Strength/Sequence3.0 Tesla/DTI acquired with diffusion‐weighted echo planar imaging (EPI). AssessmentWe performed whole‐brain fiber tractography from DTI images. The cortical plate of each diffusion atlas was segmented and parcellated into 78 regions derived from the Edinburgh Neonatal Atlas (ENA33). Connectivity matrices were computed, representing normalized fiber connections between nodes. We examined the relationship between global efficiency (GE), local efficiency (LE), small‐worldness (SW), nodal efficiency (NE), and betweenness centrality (BC) with gestational age (GA) and with laterality. Statistical TestsLinear regression was used to analyze changes in GE, LE, NE, and BC throughout gestation, and to assess changes in laterality. Thet‐tests were used to assess SW.P‐values were corrected using Holm‐Bonferroni method. A correctedP‐value <0.05 was considered statistically significant. ResultsNetwork analysis revealed a significant weekly increase in GE (5.83%/week, 95% CI 4.32–7.37), LE (5.43%/week, 95% CI 3.63–7.25), and presence of SW across GA. No significant hemisphere differences were found in GE (P = 0.971) or LE (P = 0.458). Increasing GA was significantly associated with increasing NE in 41 nodes, increasing BC in 3 nodes, and decreasing BC in 2 nodes. Data ConclusionExtensive network development and refinement occur in the second and third trimesters, marked by a rapid increase in global integration and local segregation. Level of Evidence3 Technical EfficacyStage 2
more »
« less
Precise tracking of tip-induced structural variation at the single-chemical-bond limit
Abstract Sub-nanometer-resolved TERS provides a systematic way for investigating tip-molecule interaction and molecular motions, enabling a promising approach to examine on-surface reaction mechanisms and catalysis at the microscopic level.
more »
« less
- Award ID(s):
- 1944796
- PAR ID:
- 10390736
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Light: Science & Applications
- Volume:
- 12
- Issue:
- 1
- ISSN:
- 2047-7538
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract MotivationMapping positional features from one-dimensional (1D) sequences onto three-dimensional (3D) structures of biological macromolecules is a powerful tool to show geometric patterns of biochemical annotations and provide a better understanding of the mechanisms underpinning protein and nucleic acid function at the atomic level. ResultsWe present a new library designed to display fully customizable interactive views between 1D positional features of protein and/or nucleic acid sequences and their 3D structures as isolated chains or components of macromolecular assemblies. Availability and implementationhttps://github.com/rcsb/rcsb-saguaro-3d. Supplementary informationSupplementary data are available at Bioinformatics online.more » « less
-
BackgroundWater content is a key parameter for simulating tissue swelling and nutrient diffusion. Accurately measuring water content throughout the intervertebral disc (NP = nucleus pulposus; AF = annulus fibrosus) is important for developing patient‐specific models. Water content is measured using destructive techniques, Quantitative MRI has been used to estimate water content and detect early degeneration, but it is dependent on scan parameters, concentration of free water molecules, and fiber architecture. PurposeTo directly measure disc‐tissue water content using quantitative MRI and compare MRI‐based measurements with biochemical assays, and to quantify changes in disc geometry due to compression. Study TypeBasic science, controlled. SpecimenTwenty bone‐disc‐bone motion segments from skeletally mature bovines. Field Strength/Sequence7T/3D fast low angle shot (FLASH) pulse sequence and a T2rapid imaging with refocused echoes (RARE) sequence. AssessmentDisc volumes, NP and AF volumetric water content, and T2relaxation times were measured through MRI; NP and AF tissue gravimetric water content, mass density, and glycosaminoglycan content were measured through a biochemical assay. Statistical TestsCorrelations between MRI‐based measurement and biochemical composition were evaluated using Pearson's linear regression. ResultsMechanical dehydration resulted in a decrease in disc volume by up to 20% and a decrease in disc height by up to 35%. Direct water content measurements for the NP was achieved by normalizing MRI‐based spin density by NP mass density (1.10 ± 0.03 g/cm3). However, the same approach underestimated water content in the AF by ~10%, which may be due to a higher concentration of collagen fibers and bound water molecules. Data ConclusionSpin density or spin density normalized by mass density to estimate NP and AF water content was more accurate than correlations between water content and relaxation times. Mechanical dehydration decreased disc volume and disc height, and increased maximum cross‐sectional area. Level of Evidence Technical Efficacy Stage J. Magn. Reson. Imaging 2020;52:1152–1162.more » « less
-
Abstract ObjectiveLeverage electronic health record (EHR) audit logs to develop a machine learning (ML) model that predicts which notes a clinician wants to review when seeing oncology patients. Materials and MethodsWe trained logistic regression models using note metadata and a Term Frequency Inverse Document Frequency (TF-IDF) text representation. We evaluated performance with precision, recall, F1, AUC, and a clinical qualitative assessment. ResultsThe metadata only model achieved an AUC 0.930 and the metadata and TF-IDF model an AUC 0.937. Qualitative assessment revealed a need for better text representation and to further customize predictions for the user. DiscussionOur model effectively surfaces the top 10 notes a clinician wants to review when seeing an oncology patient. Further studies can characterize different types of clinician users and better tailor the task for different care settings. ConclusionEHR audit logs can provide important relevance data for training ML models that assist with note-writing in the oncology setting.more » « less
-
Abstract ObjectiveThis Emerging Ideas report explores families' (parents and their children) uses and gratification for ChatGPT. BackgroundGenerative artificial intelligence–based conversational agents, such as ChatGPT, can be used to accomplish a variety of tasks, yet little is known about how and why parents and their children may use these technologies. MethodsWe conducted semistructured qualitative and exploratory interviews with 12 U.S.‐based families that had experience sharing a ChatGPT account. Families were recruited using social media advertisements, and at least one child and one parent joined the interview. We asked families about what they used ChatGPT for and why they used the platform. ResultsFamilies reported four main motivators for using ChatGPT: (a) information seeking, (b) enhancing productivity, (c) entertainment, and (d) social bonding. Potential barriers to use included concerns about (a) ChatGPT's credibility and capabilities, (b) being less familiar with using ChatGPT, (c) the platform's ethical implications, and (d) possible privacy risks. ConclusionFamilies use ChatGPT for various purposes, but their uses and gratifications sometimes may differ depending on their perceptions of and experiences with the platform. ImplicationsOur findings suggest that with some improvements, ChatGPT has the potential to be a useful tool for both individual and shared use in families.more » « less
