An Improved Detection Algorithm for Ischemic Stroke NCCT Based on YOLOv5

Cerebral stroke (CS) is a heterogeneous syndrome caused by multiple disease mechanisms. Ischemic stroke (IS) is a subtype of CS that causes a disruption of cerebral blood flow with subsequent tissue damage. Noncontrast computer tomography (NCCT) is one of the most important IS detection methods. It is difficult to select the features of IS CT within computational image analysis. In this paper, we propose AC-YOLOv5, which is an improved detection algorithm for IS. The algorithm amplifies the features of IS via an NCCT image based on adaptive local region contrast enhancement, which then detects the region of interest via YOLOv5, which is one of the best detection algorithms at present. The proposed algorithm was tested on two datasets, and seven control group experiments were added, including popular detection algorithms at present and other detection algorithms based on image enhancement. The experimental results show that the proposed algorithm has a high accuracy (94.1% and 91.7%) and recall (85.3% and 88.6%) rate; the recall result is especially notable. This proves the excellent performance of the accuracy, robustness, and generalizability of the algorithm

Using Magnetic Resonance Imaging to Study Enzymatic Hydrogelation

Herein, we report, for the first time, the use of MRI methods to study enzymatic hydrogelation. Supramolecular hydrogels have been exploited as biomaterials for many applications. However, behaviors of the water molecules encapsulated in hydrogels have not been fully understood. In this work, we designed a precursor <b>1</b> which could self-assemble into nanofibers and form hydrogel <b>I</b> (gel <b>I</b>) upon the catalysis of phosphatase. The differences of mechanic property, pore size, water diffusion rate, and magnetic resonance relaxation times <i>T</i>₁ and <i>T</i>₂ of gel <b>I</b> containing different concentrations of <b>1</b> were systematically studied and analyzed. <i>T</i>₁, <i>T</i>₂, and diffusion-weighted ¹H MR images from gel <b>I</b> phantoms were obtained at 9.4 T. Analyses of the MRI data uncovered how the density of the nanofiber networks affects the relaxation behaviors of the water protons encapsulated in such hydrogels. Rheological analyses and cryo-TEM observations showed increased gel elasticities with increased concentrations of <b>1</b> while the pore sizes of gel <b>I</b> decreased. This also resulted in an increase in the proton relaxation rate (i.e., shortened <i>T</i>₁, <i>T</i>₂, and apparent diffusion coefficient (ADC)) for the water encapsulated in the hydrogel. With MRI, our study provides a new in vitro method to potentially mimic and study in vivo diseases that involve fibrous aggregates

Multifunctional Fluorescent Probe for Sequential Detections of Glutathione and Caspase‑3 in Vitro and in Cells

Herein, we report a new “On–On” strategy based on the assembly and disassembly of fluorescein isothiocyanate nanoparticles (FITC-NPs) for sequential detections of glutathione (GSH) and caspase-3 (Casp3) with a multifunctional fluorescent probe <b>1</b>. Theoretical investigations revealed the underlying mechanism that satisfactorily explained experimental results of such consecutive enhancements of fluorescence. Using this probe, we also successfully imaged the Casp3 activity in apoptotic cells

Nanocomputed Tomography Imaging of Bacterial Alkaline Phosphatase Activity with an Iodinated Hydrogelator

Alkaline phosphatase (ALP) is an important enzyme, but direct imaging of ALP activity with high spatiotemporal resolution remains challenging. In this work, we rationally designed an iodinated hydrogelator precursor Nap-Phe-Phe­(I)-Tyr­(H₂PO₃)-OH (<b>1P</b>) which self-assembles into nanofibers to form hydrogel under the catalysis of ALP. With this property of concentrating iodine atoms at the locations of ALP, <b>1P</b> was successfully applied for direct nanocomputed tomography (nano-CT) imaging of ALP activity in bacteria for the first time. We envision that, on the basis of this pioneering work, new hydrogelators containing more iodine atoms (e.g., five iodine atoms in <b>1P</b>) will be designed for better nano-CT imaging of ALP activity with higher CT contrast in the near future

Nanocomputed Tomography Imaging of Bacterial Alkaline Phosphatase Activity with an Iodinated Hydrogelator

Alkaline phosphatase (ALP) is an important enzyme, but direct imaging of ALP activity with high spatiotemporal resolution remains challenging. In this work, we rationally designed an iodinated hydrogelator precursor Nap-Phe-Phe­(I)-Tyr­(H₂PO₃)-OH (<b>1P</b>) which self-assembles into nanofibers to form hydrogel under the catalysis of ALP. With this property of concentrating iodine atoms at the locations of ALP, <b>1P</b> was successfully applied for direct nanocomputed tomography (nano-CT) imaging of ALP activity in bacteria for the first time. We envision that, on the basis of this pioneering work, new hydrogelators containing more iodine atoms (e.g., five iodine atoms in <b>1P</b>) will be designed for better nano-CT imaging of ALP activity with higher CT contrast in the near future