A Multisource Situation Information Fusion Method Based on Dynamic Evidence Combination

To address the problems of fusion efficiency, detection rate (DR), and false detection rate (FDR) that are associated with existing information fusion methods, a multisource information fusion method featuring dynamic evidence combination based on layer clustering and improved evidence theory is proposed in this study. First, the original alerts are hierarchically clustered and conflicting evidence is eliminated. Then, dynamic evidence combination is applied to fuse the condensed alerts, thereby improving the efficiency and accuracy of the fusion. The experimental results show that the proposed method is superior to current fusion methods in terms of fusion efficiency, DR, and FDR.

Aspiration-assisted freeform bioprinting of mesenchymal stem cell spheroids within alginate microgels

Aspiration-assisted freeform bioprinting (AAfB) has emerged as a promising technique for precise placement of tissue spheroids in three-dimensional (3D) space for fabrication of tissues. For successful embedded bioprinting using AAfB, an ideal support bath should possess shear-thinning behavior and yield-stress to obtain tightly fused assembly of bioprinted spheroids. Several studies have demonstrated support baths for embedded bioprinting, but these materials pose major challenges due to their low biocompatibility, opaqueness, complex and prolonged preparation procedures, and limited spheroid fusion efficacy. In this study, to circumvent the aforementioned limitations, we present the feasibility of AAfB of human mesenchymal stem cell (hMSC) spheroids in alginate microgels as a support bath. First, alginate microgels were prepared with different particle sizes modulated by blending time and concentration, followed by determination of the optimal bioprinting conditions by the assessment of rheological properties, bioprintability, and spheroid fusion efficiency. The bioprinted and consequently self-assembled tissue structures made of hMSC spheroids were osteogenically induced for bone tissue formation. Alongside, we investigated the effects of peripheral blood monocyte-derived osteoclast incorporation into the hMSC spheroids in heterotypic bone tissue formation. We demonstrated that alginate microgels enabled unprecedented positional accuracy (~5%), transparency for visualization, and improved fusion efficiency (~97%) of bioprinted hMSC spheroids for bone fabrication. This study demonstrates the feasibility of using alginate microgels as a support bath for many different applications including but not limited to freeform bioprinting of spheroids, cell-laden hydrogels, and fugitive inks to form viable tissue constructs.

Type 2 sclerotic Modic change affect fusion result in patients undergoing PLIF with pedicle screw instrumentation: a retrospective study

Background Bony fusion rate was significantly lower in patients with type 3 Modic change than patients with normal endplates. It is not known whether there are relevant differences in fusion efficiency among patients with type 2 sclerotic Modic change or non-sclerotic Modic change, or no Modic change. Methods A retrospective study contained 196 lumbar segments in 123 subjects undergoing posterior lumbar interbody fusion (PLIF) with pedicle screw instrumentation (PSI) to assess the effect of type 2 sclerotic Modic change on fusion efficiency. These endplates were allocated into groups A, B, and C, according to their Modic changes. Group A had endplates with type 2 Modic change and endplate sclerosis. Group B had type 2 Modic change without endplate sclerosis. Group C had neither Modic change nor endplate sclerosis. The presence of Modic change was determined by magnetic resonance imaging (MRI). Endplate sclerosis in type 2 Modic change was detected by computed tomography (CT) before the operation. We collected CT data 3 months to more than 24 months after operation in patients to assess bony fusion. Results Incidences of bony fusion were 58.8% in group A, 95.0% in group B, 94.3% in group C. The bony fusion rate was significantly lower in group A than in either group B or C. There was no significant difference between groups B and C. Thus, endplates with type 2 sclerotic Modic change had a lower fusion rate in patients undergoing PLIF with PSI. Conclusion Type 2 sclerotic Modic change could be an important factor that affects solid bony fusion in patients undergoing PLIF with PSI. CT may help diagnose endplate sclerosis in patients with type 2 change and inform the choice of the best site for spinal fusion.

The role of PI(4,5)P2 and synaptotagmin in membrane fusion - an in vitro study

Synaptotagmin-1 (syt-1) is known to trigger fusion of neuronal synaptic vesicles with the presynaptic membrane by recognizing acidic membrane lipids. In particular, binding to PI(4,5)P2 is believed to be crucial for its function as a calcium sensor. We propose a mechanism for syt-1 to interact with anionic bilayers and promote fusion in the presence of SNARE proteins. We found that in the absence of Ca2+ the binding of syt-1 to membranes depends on the PI(4,5)P2 content. Addition of Ca2+ switches the interaction forces from weak to strong eventually exceeding the cohesion of the C2A domain, while the interaction between PI(4,5)P2 and the C2B domain was preserved even in the absence of Ca2+ or phosphatidylserine. Fusion of large unilamellar vesicles equipped with syt-1 and synaptobrevin with freestanding target membranes composed of PS/PI(4,5)P2 show an increased fusion speed, and by effective suppression of stalled intermediate states, a larger number of full fusion events. Fusion efficiency could be maximized when irreversible docking is additionally prevented by addition of multivalent anions. The picture that emerges is that syt-1 remodels the membrane in the presence of calcium and PIP2, thereby substantially increasing the efficiency of membrane fusion by avoiding stalled intermediate states.

Biomimetic Curvature and Tension-Driven Membrane Fusion Induced by Silica Nanoparticles

Membrane fusion is a key process to develop new technologies in synthetic biology, where artificial cells function as biomimetic chemical microreactors. Fusion events in living cells are intricate phenomena that require the coordinate action of multicomponent protein complexes. However, simpler synthetic tools to control membrane fusion in artificial cells are highly desirable. Native membrane fusion machinery mediates fusion driving a delicate balance of membrane curvature and tension between two closely apposed membranes. Here we show that silica nanoparticles (SiO₂ NPs) at a size close to the cross-over between tension-driven and curvature-driven interaction regimes initiate efficient fusion of biomimetic model membranes. Fusion efficiency and mechanisms are studied by Förster Resonance Energy Transfer (FRET) and confocal fluorescence microscopy. SiO₂ NPs induce a slight increase in lipid packing likely to increase the lateral tension of the membrane. We observe a connection between membrane tension and fusion efficiency. Finally, real-time confocal fluorescence microscopy reveals three distinct mechanistic pathways for membrane fusion. SiO₂ NPs show significant potential for inclusion in the synthetic biology toolkit for membrane remodelling and fusion in artificial cells.

Biomimetic Curvature and Tension-Driven Membrane Fusion Induced by Silica Nanoparticles

Membrane fusion is a key process to develop new technologies in synthetic biology, where artificial cells function as biomimetic chemical microreactors. Fusion events in living cells are intricate phenomena that require the coordinate action of multicomponent protein complexes. However, simpler synthetic tools to control membrane fusion in artificial cells are highly desirable. Native membrane fusion machinery mediates fusion driving a delicate balance of membrane curvature and tension between two closely apposed membranes. Here we show that silica nanoparticles (SiO₂ NPs) at a size close to the cross-over between tension-driven and curvature-driven interaction regimes initiate efficient fusion of biomimetic model membranes. Fusion efficiency and mechanisms are studied by Förster Resonance Energy Transfer (FRET) and confocal fluorescence microscopy. SiO₂ NPs induce a slight increase in lipid packing likely to increase the lateral tension of the membrane. We observe a connection between membrane tension and fusion efficiency. Finally, real-time confocal fluorescence microscopy reveals three distinct mechanistic pathways for membrane fusion. SiO₂ NPs show significant potential for inclusion in the synthetic biology toolkit for membrane remodelling and fusion in artificial cells.

Tumor-tumor Cell Fusion Hybrids Obtained by the Modified PHA-DMSO-PEG Method Promote Temozolomide Resistance in Glioma

Background: Cell fusion and the subsequent aneuploidy are commonly observed in different kinds of tumor. In glioma, cell fusion and the number of the polyploid giant cells were found to be augmented with the tumor grades (WHO Ⅰ-Ⅳ) and closely related to poor prognosis. Phytohemagglutinin (PHA) holds an ability to induce cell-cell membrane contact and accelerates the cell fusion process mediated by the fusogenic agent polyethylene glycol (PEG). Dimethyl sulfoxide (DMSO) is well known as a cryoprotective agent involving in cell cryopreservation. In this study, we aim to obtain the glioma fusion hybrids by the modified fusion method in vitro, and then investigate the pathological consequences and the related molecular mechanism with the cell hybrids.Methods: Glioma cells were labelled by lentiviruses infection. The PEG fusion efficiency was respectively improved by the addition of PHA and DMSO, and quantified by flow cytometry. Then, fusion hybrids were obtained by puromycin screening and fluorescence-activated cell sorting (FACS). Furthermore, DNA content was analyzed through flow cytometry. Cell proliferation rate and cell viability under temozolomide (TMZ) was detected by CCK-8 assay. Lastly, the related gene expression was measured through qRT-PCR and Western blotting. Results: Glioma cell-cell contact was achieved by adding certain concentration of PHA in vitro. Tumor-tumor cell fusion efficiency was improved by PHA and DMSO. Glioma fusion hybrids were successfully obtained after puromycin screening and FACS. Cell size, DNA content and chromosome numbers of the fusion hybrids were almost twice that of the parental glioma cells. Moreover, glioma fusion hybrids showed an enhanced TMZ resistance potential compared to the parental cells, and also the MGMT expression was up-regulated in the hybrids.Conclusions: We successfully obtained the glioma tumor-tumor cell fusion hybrids through the modified PHA-DMSO-PEG fusion method. Cell fusion may contribute to TMZ resistance in glioma, thus inhibition of cell fusion could be a promising orientation to improve TMZ resistance. Moreover, combining TMZ and MGMT inhibitor could be a beneficial approach in patients with glioma polyploid giant cells.