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A series of linear isocyanate-free polyurethanes (NIPUs) were obtained via the aminolysis of erythritol dicarbonate (EDC) with polyethers (diamino-PEG, diamino-PPO, and diamino-PEG/PPO) and 1,12-diaminododecane (DADD), which acts as a chain extender to form hard segments. The obtained NIPUs contained different concentrations of DADD relative to the polyether (72.5-80 wt%). A detailed chemical structure analysis of the synthesized NIPU was performed using a combination of FTIR and H NMR. FTIR spectra confirmed that the EDC/DADD segments formed a network of hydrogen bonds. This is reflected in WAXD diffractograms showing ordered crystalline domains originating in DADD. The reflections assigned to the EDC/DADD segments exhibited changes in their position and intensity with decreasing concentration, indicating an increase in interplanar spacing and a loss of higher-order order. WAXD also showed that the soft segments of PEG and PEG/PPO retain their ordered crystal structure regardless of the EDC/DADD content. At a larger length scale, SAXS revealed similar micromorphology for the different polyethers, with a broad peak indicating long-range order in the EDC/DADD-rich segments and a weak separation of the soft and hard phases. DSC analyses confirmed the complex phase behavior, where the PEG-based materials showed melting of crystalline fragments, and the amorphous PPO showed a glass transition. DMA indicated the stability of the glass transition temperature in the PPO samples and the presence of an unusual structural transition. The results emphasize the influence of the type of poly(ether) on the thermal and microphase properties of the studied non-isocyanate polyurethanes.
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http://dx.doi.org/10.3390/molecules30142912 | DOI Listing |
Cureus
August 2025
Internal Medicine, Shifa International Hospital Islamabad, Islamabad, PAK.
One of the relatively common anatomical variants of coronary vessels that is often overlooked in clinical practice is coronary artery tortuosity (CAT). CAT can have a significant impact on coronary blood flow and procedural outcomes during percutaneous coronary intervention (PCI). It is defined by bends, curves, or loops within the coronary vasculature that can lead to increased vascular resistance.
View Article and Find Full Text PDFDigit Health
September 2025
Department of Respiratory and Critical Care Medicine, The Sixth Affiliated Hospital of Xinjiang Medical University, Urumqi, China.
Objective: Accurate segmentation of breast lesions, especially small ones, remains challenging in digital mammography due to complex anatomical structures and low-contrast boundaries. This study proposes DVF-YOLO-Seg, a two-stage segmentation framework designed to improve feature extraction and enhance small-lesion detection performance in mammographic images.
Methods: The proposed method integrates an enhanced YOLOv10-based detection module with a segmentation stage based on the Visual Reference Prompt Segment Anything Model (VRP-SAM).
J Dent
September 2025
Maxillofacial Prosthodontist, Surgical Prosthodontist Private Practice Fort Lee, NJ, and Manhattan, New York, USA. Electronic address:
Objectives: Precise implant placement in the anterior and posterior maxilla often presents challenges due to variable bone and soft tissue anatomy. Many clinicians elect a freehand surgical approach because conventional surgical guides may not always be easy to design, fabricate, or utilize. Guided surgery has been proven to have advantages over freehand surgical protocols and therefore, the present study proposed utilizing the nasopalatine canal (NPC) as an anatomical reference and point of fixation for a novel rotational path surgical template during computer-aided implant surgery (CAIS).
View Article and Find Full Text PDFACS Sens
September 2025
The State Key Laboratory of Mechanical System and Vibration, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Tactile sensing arrays play a crucial role in human-machine interaction, robotics, and artificial intelligence by enabling the perception of physical stimuli on robotic surfaces or human skin. However, skin-attachable sensor arrays still suffer from strain interference and signal crosstalk under stretching or bending, particularly on curved or deformable surfaces. Here, we present a stretchable tactile array that is both strain-insensitive and crosstalk-suppressed, achieved via a hierarchically segmented design that mitigates lateral and vertical deformations synergistically.
View Article and Find Full Text PDFEur Radiol Exp
September 2025
Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada.
Background: Lung lobe segmentation is required to assess lobar function with nuclear imaging before surgical interventions. We evaluated the performance of open-source deep learning-based lung lobe segmentation tools, compared to a similar nnU-Net model trained on a smaller but more representative clinical dataset.
Materials And Methods: We collated and semi-automatically segmented an internal dataset of 164 computed tomography scans and classified them for task difficulty as easy, moderate, or hard.