Differentiating Metabolites Formed from de Novo Synthesis versus Macromolecule Decomposition

We present a novel approach utilizing stable isotope labeling and mass spectrometric detection, which we term differential kinetic flux profiling, to probe dynamic cellular metabolic changes in response to environmental perturbations. Cells are switched into isotope-labeled media both shortly before and separately shortly after the perturbation, and the kinetics of subsequent labeling of intracellular metabolites measured by liquid chromatography-tandem mass spectrometry. The combined data enable measurement of both metabolite formation from macromolecular decomposition and small molecule flux changes triggered by the environmental perturbation. This approach is exemplified using 15N-ammonia labeling of Escherichia coli to probe changes in amino acid metabolism induced by carbon starvation. We find that carbon starvation almost fully halts amino acid fluxes, and that the trace remaining flux is almost completely driven by protein degradation. The general approach of differential kinetic flux profiling should be of wide utility for dissecting cellular metabolic responses to changing environmental conditions

Ligand–Receptor Interaction Triggers Hopping and Sliding Motions on Living Cell Membranes

Exploring the surface-capturing and releasing processes of nanocargo on the living cell membrane is critical for understanding the membrane translocation process. In this work, we achieve total internal reflection scattering (TIRS) illumination on a commercial dark-field optical microscope without the introduction of any additional optical components. By gradually reducing the diaphragm size in the excitation light path, the angle of the incident beam can be well manipulated. Under optimal conditions, the excitation light can be totally reflected at the glass/water interface, resulting in a thin layer of evanescent field for TIRS illumination. Due to the exponential decay feature of the evanescent field, the displacement of the nanocargo along the vertical direction can be directly resolved in the intensity track. With this method, we selectively monitor the dynamics of the transferrin-modified nanocargo on the living cell membrane. Transition between confined diffusion and long-range searching is involved in the binding site recognition process, which exhibits non-Gaussian and nonergodic-like behavior. More interestingly, 2D fast sliding and 3D hopping motions are also distinguished on the fluidic cell membrane, which is essentially modulated by the strength of ligand–receptor interactions, as revealed by the free-energy profiles. These heterogeneous and dynamic interactions together control the diffusion mode of the nanocargo on the lipid membrane and, thus, determine the cellular translocation efficiency

Nanoparticle-Coupled Single-Molecule Kinetic Fingerprinting for Enzymatic Activity Detection

The sensitive and accurate detection of biomarkers plays an important role in clinical diagnosis and drug discovery. Currently, amplification-based methods for biomarker detection are widely explored. However, the key challenges of these methods are limited reproducibility and high background noise. To overcome these limitations, we develop a robust plasmonic nanoparticle-coupled single-molecule kinetic fingerprinting (PNP-SMKF) method to achieve ultrasensitive detection of protein kinase A (PKA). Transient binding of a short fluorescent probe with the genuine target produces a distinct kinetic signature that is completely different from that of the background signal, allowing us to recognize PKA sensitively. Importantly, integrating a plasmonic nanoparticle efficiently breaks the concentration limit of the imager strand for single-molecule imaging, thus achieving a much faster imaging speed. A limit of detection (LOD) of as low as 0.0005 U/mL is readily realized. This method holds great potential as a versatile platform for enzyme detection and inhibitor screening in the future

C₁₂mimBr Ionic Liquid/SDS Vesicle Formation and Use As Template for the Synthesis of Hollow Silica Spheres

The phase behavior of an aqueous catanionic surfactant system, composed of a long-chain imidazolium ionic liquid 1-dodecyl-3-methylimidazolium bromide (C12mimBr) and sodium dodecyl sulfate (SDS), is described. The phase diagram of the catanionic system was determined by electrical conductivity measurements and the formation of vesicles in a birefringent Lα phase characterized by transmission electron microscopy (TEM) and freeze-fracture transmission electron microscopy (FF-TEM). Rheological measurements were used to characterize the macroscopic properties of the birefringent Lα phase. Both electrostatic and hydrophobic interactions contribute to the vesicle formation in the catanionic system. Compared to the DTAB/SDS aqueous solution, differences between the imidazolium and trimethylammonium headgroups geometric packing and charge density induce the different phase behavior in each system. Silica hollow spheres, with diameters 30−60 nm and a wall thickness of 8−10 nm, were prepared by using the vesicles as the templates. The hollow silica spheres were characterized by TEM, scanning electron microscopy (SEM), and nitrogen adsorption−desorption. The results suggest additional application for ionic liquid based vesicles to be used as templates for the synthesis of hollow inorganic materials

Video1_Virtual Reality for Interactive Medical Analysis.MP4

Molecular imaging along with 3-dimensional (3-D) or 4-D (3-D spatial + 1-D temporal) visualization is widely used in clinical diagnosis and surgical planning. However, the pre-defined perspective and confined manipulation limit the in-depth exploration and analysis in 3-D/4-D. To overcome this obstacle, we utilized virtual reality (VR) to interact with CT images of the cardiopulmonary system in a 3-D immersive environment. We implemented manipulative functionalities into the VR environment that altered the cardiopulmonary models to interactively generate new data analysis perspectives. We successfully sliced a CT cardiac model showing in-depth surface visualizations of the ventricles and atria. Our customized framework enables enhanced data interpretation interactivity of CT images and establishes a user-directed manipulative VR platform derived from imaging results for remote medical practices including training, education, and investigation.</p

Video2_Virtual Reality for Interactive Medical Analysis.MP4

Molecular imaging along with 3-dimensional (3-D) or 4-D (3-D spatial + 1-D temporal) visualization is widely used in clinical diagnosis and surgical planning. However, the pre-defined perspective and confined manipulation limit the in-depth exploration and analysis in 3-D/4-D. To overcome this obstacle, we utilized virtual reality (VR) to interact with CT images of the cardiopulmonary system in a 3-D immersive environment. We implemented manipulative functionalities into the VR environment that altered the cardiopulmonary models to interactively generate new data analysis perspectives. We successfully sliced a CT cardiac model showing in-depth surface visualizations of the ventricles and atria. Our customized framework enables enhanced data interpretation interactivity of CT images and establishes a user-directed manipulative VR platform derived from imaging results for remote medical practices including training, education, and investigation.</p

Image7_Integrated Analysis of Angiogenesis Related lncRNA-miRNA-mRNA in Patients With Coronary Chronic Total Occlusion Disease.PNG

Background: Coronary chronic total occlusion (CTO) disease is common and its specific characteristic is collateral formation. The Integrated analysis of angiogenesis related lncRNA-miRNA-mRNA network remains unclear and might provide target for future studies.Methods: A total of five coronary artery disease (control group) and five CTO (CTO group) patients were selected for deep RNA and miRNA sequencing. The expression profiles of lncRNAs, mRNAs circRNA and miRNAs were obtained. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were then performed. The expression of a 14q32 miRNA gene cluster, including miRNA-494, miRNA-495 and miRNA-329, were selected to be determined in another larger patient cohort. Analysis of the lncRNA-miRNA495-mRNA network was constructed to find potential targets for future studies.Results: A total of 871 lncRNAs, 1,080 mRNAs, 138 circRNAs and 56 miRNAs were determined as differentially expressed (DE) in CTO patients compared with control patients. GO and KEGG analyses revealed that the top terms included MAPK signaling pathway, HIF-1 signaling pathway, EGFR tyrosine kinase inhibitor resistance, embryonic organ development, wound healing, MAPK signaling pathway and JAK-STAT signaling pathway, which are related to angiogenesis. The expression of miRNA-494, miRNA-495 and miRNA-329 were all significantly down-regulated in CTO patients and they were confirmed to be down-regulated in another cohort of 68 patients. Then we divided the CTO patients into two groups according to CC grade (poor CC group, CC = 0 or one; good CC group, CC = 2). MiRNA-494, miRNA-495 and miRNA-329 were found to be down-regulated in good CC group compared with poor CC group. Analysis of the lncRNA-miRNA495-mRNA network showed 3 DE lncRNA sponges (NONHSAG008675, NONHSAG020957 and NONHSAG010989), 4 DE lncRNA targets (NONHSAT079547.2, NONHSAT081776.2, NONHSAT148555.1 and NONHSAT150928.1) and 2 DE mRNA targets (RAD54L2 and ZC3H4) of miRNA495.Conclusion: This study revealed that the lncRNA-miRNA-mRNA network might play a critical role in angiogenesis in CTO patients.</p

Image2_Integrated Analysis of Angiogenesis Related lncRNA-miRNA-mRNA in Patients With Coronary Chronic Total Occlusion Disease.PNG

Background: Coronary chronic total occlusion (CTO) disease is common and its specific characteristic is collateral formation. The Integrated analysis of angiogenesis related lncRNA-miRNA-mRNA network remains unclear and might provide target for future studies.Methods: A total of five coronary artery disease (control group) and five CTO (CTO group) patients were selected for deep RNA and miRNA sequencing. The expression profiles of lncRNAs, mRNAs circRNA and miRNAs were obtained. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were then performed. The expression of a 14q32 miRNA gene cluster, including miRNA-494, miRNA-495 and miRNA-329, were selected to be determined in another larger patient cohort. Analysis of the lncRNA-miRNA495-mRNA network was constructed to find potential targets for future studies.Results: A total of 871 lncRNAs, 1,080 mRNAs, 138 circRNAs and 56 miRNAs were determined as differentially expressed (DE) in CTO patients compared with control patients. GO and KEGG analyses revealed that the top terms included MAPK signaling pathway, HIF-1 signaling pathway, EGFR tyrosine kinase inhibitor resistance, embryonic organ development, wound healing, MAPK signaling pathway and JAK-STAT signaling pathway, which are related to angiogenesis. The expression of miRNA-494, miRNA-495 and miRNA-329 were all significantly down-regulated in CTO patients and they were confirmed to be down-regulated in another cohort of 68 patients. Then we divided the CTO patients into two groups according to CC grade (poor CC group, CC = 0 or one; good CC group, CC = 2). MiRNA-494, miRNA-495 and miRNA-329 were found to be down-regulated in good CC group compared with poor CC group. Analysis of the lncRNA-miRNA495-mRNA network showed 3 DE lncRNA sponges (NONHSAG008675, NONHSAG020957 and NONHSAG010989), 4 DE lncRNA targets (NONHSAT079547.2, NONHSAT081776.2, NONHSAT148555.1 and NONHSAT150928.1) and 2 DE mRNA targets (RAD54L2 and ZC3H4) of miRNA495.Conclusion: This study revealed that the lncRNA-miRNA-mRNA network might play a critical role in angiogenesis in CTO patients.</p

Design of Thermally Activated Delayed Fluorescence Materials with High Intersystem Crossing Efficiencies by Machine Learning-Assisted Virtual Screening

Efficient intersystem crossing (ISC) and reverse ISC (RISC) processes are of vital significance for thermally activated delayed fluorescence (TADF) materials to achieve 100% internal quantum efficiency. However, it is challenging to rapidly predict the ISC/RISC rates of large amounts of TADF materials and screen promising candidates because of their flexible molecular design. Here, we perform virtual screening of 564 candidates constructed from 20 unique building blocks linking in D–A, D−π–A, and D–A–D (D′) configurations using the established machine learning models of GBRT and RF-GBRT-KNN with the Pearson’s correlation coefficients (r) of 0.89 and 0.82, respectively. Novel descriptors of ΔELL, Polar, and ΔETT for predicting ISC/RISC rates were proposed, and nine TADF molecules with the predicted ISC and RISC rates of >7 × 107 and 2 × 105 s–1, respectively, were revealed. We provide an efficient approach to predicting ISC and RISC rates of TADF molecules on a large scale, elucidating important building blocks and architectures to design high-performance optoelectronic materials for experimental explorations

Data_Sheet_1_Comparison of Clinical Features and Outcomes of Appendectomy in Elderly vs. Non-Elderly: A Systematic Review and Meta-Analysis.doc

BackgroundThe objective of this study is to compare clinical and surgical outcomes of appendectomy among elderly and non-elderly subjects.MethodsA systematic search was conducted on PubMed, Scopus, and Google academic databases. Studies, observational in design, that compared peri-and postoperative outcomes of appendectomy, in patients with acute appendicitis, between elderly and non-elderly/younger subjects were considered for inclusion. Statistical analysis was performed using STATA software.ResultsA total of 15 studies were included. Compared to non-elderly patients, those that were elderly had an increased risk of complicated appendicitis [relative risk (RR), 2.38; 95% CI: 2.13, 2.66], peritonitis [RR, 1.88; 95% CI: 1.36, 2.59], and conversion from laparoscopic to open appendectomy [RR, 3.02; 95% CI: 2.31, 3.95]. The risk of overall postoperative complications [RR, 2.59; 95% CI: 2.19, 3.06], intra-abdominal abscess [RR, 1.84; 95% CI: 1.15, 2.96], wound infection [RR, 3.80; 95% CI: 2.57, 5.61], and use of postoperative drainage [RR, 1.14; 95% CI: 1.09, 1.19] was higher among the elderly. The risk of readmission (30 days) [RR, 1.61; 95% CI: 1.16, 2.24] and mortality (30 days) [RR, 12.48; 95% CI: 3.65, 42.7] was also higher among elderly.ConclusionsFindings suggest an increased risk of peri-and postoperative complications among elderly subjects undergoing appendectomy, compared to non-elderly subjects.Systematic Review Registrationhttps://www.crd.york.ac.uk/prospero/, identifier: CRD42021286157.</p