Foreground Estimation in Neuronal Images With a Sparse-Smooth Model for Robust Quantification

3D volume imaging has been regarded as a basic tool to explore the organization and function of the neuronal system. Foreground estimation from neuronal image is essential in the quantification and analysis of neuronal image such as soma counting, neurite tracing and neuron reconstruction. However, the complexity of neuronal structure itself and differences in the imaging procedure, including different optical systems and biological labeling methods, result in various and complex neuronal images, which greatly challenge foreground estimation from neuronal image. In this study, we propose a robust sparse-smooth model (RSSM) to separate the foreground and the background of neuronal image. The model combines the different smoothness levels of the foreground and the background, and the sparsity of the foreground. These prior constraints together contribute to the robustness of foreground estimation from a variety of neuronal images. We demonstrate the proposed RSSM method could promote some best available tools to trace neurites or locate somas from neuronal images with their default parameters, and the quantified results are similar or superior to the results that generated from the original images. The proposed method is proved to be robust in the foreground estimation from different neuronal images, and helps to improve the usability of current quantitative tools on various neuronal images with several applications.

Development And Characterization Of Fluorescent Mannose- And Sialic Acid Based Chemical Probes For Lectin Discovery And Enzyme Studies

BODIPY (4,4–Difluoro-4-boro-3a,4a-diaza-s-indacene) dyes are relatively nonpolar fluorescent molecules used as biological labeling reagents. The advantages of using BODIPY dyes as tags include their unique photochemical properties, allowing for an easy and sensitive monitoring of target components. This thesis will discuss the synthesis of novel fluorescent “BODIPY”-labeled carbohydrate-based chemical probes and highlight their uses in different biological applications. In chapter one, we have focused on the development of BODIPY-mannose-based chemical probes for the discovery and characterization of mannose-binding lectins on surfaces of Actinobacteria. The synthesis of these probes and their efficiency to detect mannose-binding lectins using different techniques such as Fluorescence microscopy and flow cytometry are discussed. In chapter two, we have focused on the chemo-enzymatic synthesis of BODIPY-sialic acid based chemical probes for enzymatic detection of specific glycoconjugates on proteins. The use of these probes as donor substrates to probe the enzymes involved in glycan sialylation are discussed

Development And Characterization Of Fluorescent Mannose- And Sialic Acid Based Chemical Probes For Lectin Discovery And Enzyme Studies

BODIPY (4,4–Difluoro-4-boro-3a,4a-diaza-s-indacene) dyes are relatively nonpolar fluorescent molecules used as biological labeling reagents. The advantages of using BODIPY dyes as tags include their unique photochemical properties, allowing for an easy and sensitive monitoring of target components. This thesis will discuss the synthesis of novel fluorescent “BODIPY”-labeled carbohydrate-based chemical probes and highlight their uses in different biological applications. In chapter one, we have focused on the development of BODIPY-mannose-based chemical probes for the discovery and characterization of mannose-binding lectins on surfaces of Actinobacteria. The synthesis of these probes and their efficiency to detect mannose-binding lectins using different techniques such as Fluorescence microscopy and flow cytometry are discussed. In chapter two, we have focused on the chemo-enzymatic synthesis of BODIPY-sialic acid based chemical probes for enzymatic detection of specific glycoconjugates on proteins. The use of these probes as donor substrates to probe the enzymes involved in glycan sialylation are discussed

Effect of Ce3+ Co-doping on GdPO4:Tb3+ Nanoparticles: Photoluminescence and Energy Transfer Studies

Low temperature synthesis of Tb3+-doped GdPO4 nanoparticles sensitized with Ce3+ (Ce3+ = 0, 3, 5, 7 and 10 at.%) have been reported. Ethylene glycol was used as capping agent as well as reaction medium at 160 ºC. The as-prepared particles crystallized in a monoclinic structure with an average crystallite size of 25-46 nm. From the photoluminescence study, enhanced emission of Tb3+ with co-doping of Ce3+ was attributed to efficient energy transfer from the sensitizer to activator. The luminescence emission intensity increases upto 5 at.% of Ce3+ and then decreases. Less efficient energy transfer from sensitizer to the activator with increasing concentration of sensitizer may be attributed to critical concentration of Ce3+ with the host or dipole-quadrupole interaction amongst the Ce3+ ions. Moreover, presence of -OH group in the samples will make them a potential target for biological labeling and optical devices.

A Review on Electrospun Luminescent Nanofibers: Photoluminescence Characteristics and Potential Applications

<P>Background: Photoluminescent materials have been used for diverse applications in the fields of science and engineering, such as optical storage, biological labeling, noninvasive imaging, solid-state lasers, light-emitting diodes, theranostics/theragnostics, up-conversion lasers, solar cells, spectrum modifiers, photodynamic therapy remote controllers, optical waveguide amplifiers and temperature sensors. Nanosized luminescent materials could be ideal candidates in these applications. </P><P> Objective: This review is to present a brief overview of photoluminescent nanofibers obtained through electrospinning and their emission characteristics. </P><P> Methods: To prepare bulk-scale nanosized materials efficiently and cost-effectively, electrospinning is a widely used technique. By the electrospinning method, a sufficiently high direct-current voltage is applied to a polymer solution or melt; and at a certain critical point when the electrostatic force overcomes the surface tension, the droplet is stretched to form nanofibers. Polymer solutions or melts with a high degree of molecular cohesion due to intermolecular interactions are the feedstock. Subsequent calcination in air or specific gas may be required to remove the organic elements to obtain the desired composition. </P><P> Results: The luminescent nanofibers are classified based on the composition, structure, and synthesis material. The photoluminescent emission characteristics of the nanofibers reveal intriguing features such as polarized emission, energy transfer, fluorescent quenching, and sensing. An overview of the process, controlling parameters and techniques associated with electrospinning of organic, inorganic and composite nanofibers are discussed in detail. The scope and potential applications of these luminescent fibers also conversed. </P><P> Conclusion: The electrospinning process is a matured technique to produce nanofibers on a large scale. Organic nanofibers have exhibited superior fluorescent emissions for waveguides, LEDs and lasing devices, and inorganic nanofibers for high-end sensors, scintillators, and catalysts. Multifunctionalities can be achieved for photovoltaics, sensing, drug delivery, magnetism, catalysis, and so on. The potential of these nanofibers can be extended but not limited to smart clothing, tissue engineering, energy harvesting, energy storage, communication, safe data storage, etc. and it is anticipated that in the near future, luminescent nanofibers will find many more applications in diverse scientific disciplines.</P>

Hall and ion slip effects on Unsteady MHD Convective Rotating flow of Nanofluids—Application in Biomedical Engineering

There is an intense worldwide activity in the development of instrumentation for medical diagnosis and bioscreening based on biological labeling and detection of nanoparticles. Based on this profound observation, Hall and ion slip effects on magnetohydrodynamic (MHD) free convective rotating flow of nanofluids in a porous medium past a moving vertical semi-infinite flat plate are investigated. The equations for governing flow are solved analytically by perturbation approximation. The effects of various parameters on the flow are discussed through graphs and tables. The velocity increases with Hall and ion slip parameters. An increase in the convective parameter led to amplify the thermal boundary layer thickness, but when the heat generation parameter is taken into consideration, an opposite effect occurs. The skin friction coefficient increases with an increase in nanoparticle volume fraction and it reduces with increase in Hall and ion slip parameters. Outcomes disclose that the impact of thermal convection of nanoparticles has increased the temperature distribution, which helps in destroying the cancer cells during the drug delivery process.

Using pH-Activable Carbon Nanoparticles as Cell Imaging Probes

Herein, we demonstrate the fabrication of innovative pH-activable carbon nanoparticles (CNPs) based on urea and citric acid by microwave-assisted green synthesis for application in cell imaging. These CNP-based nanoprobes offer significant advantages of pH responsiveness and excellent biocompatibility. The pH responsiveness ranges from 1.0 to 4.6 and the slightly pH responsiveness ranges from 4.6 to 9.0. In addition, the pH-dependent modification of charge as well as the final diameter of the designed CNPs not only provide support as stable sensors for cell imaging under pH values from 4.6 to 9.0, but can also observe the pH change in cells from 1.0 to 4.6. Importantly, this significantly enhances the cellular internalization process resulting in tumor cell death. Together, we believe that these superior photoluminescence properties of our designed nanomaterials potentially allow for biological labeling, bioimaging, and drug delivery applications.

Recent Progress on Gold-Nanocluster-Based Fluorescent Probe for Environmental Analysis and Biological Sensing

Gold nanoclusters (AuNCs) are one of metal nanoclusters, which play a pivotal role in the recent advances in the research of fluorescent probes for their fluorescence effect. They are favored by most researchers due to their strong stability in fluorescence and adjustability in fluorescence wavelength when compared to traditional organic fluorescent dyes. In this review, we introduce various synthesis strategies of gold-nanocluster-based fluorescent probes and summarize their application for environmental analysis and biological sensing. The use of gold-nanocluster-based fluorescent probes for the analysis of heavy metals and inorganic and organic pollutants is covered in the environmental analysis while biological labeling, imaging, and detection are presented in biological sensing.

Synthesis of Fluorescent Carbon Dots by Gastrointestinal Fluid Treatment of Mongolia Har Gabur

Har Gabur is the carbide obtained from pig manure by burning. The fluorescent carbon dots (CDs) of Har Gabur were successfully synthesized through simulating the digestion process of human gastrointestinal tract. Transmission Electron Microscope (TEM) analysis showed that the average size of the prepared Har Gabur CDs was 4 nm, with good solubility in water and strong fluorescence under UV irradiation. The X-ray and Raman results showed that the Har Gabur CDs were mainly composed of oxygen “O” and carbon “C” elements, in the forms of “C=O” and “C-O.” The bond energy results showed that the nitrogen “N” atom presented as “C-N” form, which indicated that Har Gabur CDs also contain “N.” In photobleaching assay, Har Gabur CDs showed excellent light stability compared with ordinary organic dye, fluorescein, and Rhodamine B. The fluorescence intensity of Har Gabur CDs was fairly stable within a wide pH range of 3–10. When L-lysine and L-cysteine were applied for the passivation stage, the relative quantum yields were improved by 1.53 and 3.68 times, respectively. Finally, the fluorescence properties of Har Gabur CDs were tested in cells and zebrafish, illustrating that Har Gabur CD has potential in the application of biological labeling and imaging.

Increasing cell viability using Cd-free – InP/ZnS@silica@layered double hydroxide – materials for biological labeling

In this work we describe the synthesis and characterization of InP/ZnS@silica@LDH nanoparticles and, moreover, their use as biomarkers.