Synthesis and Characterization of SiO2@CNTs Microparticles: Evaluation of Microwave-Induced Heat Production

This study was focused on the growth of multi-walled carbon nanotubes (MWCNTs) on iron chloride-functionalized silica microspheres. In addition, the microwave absorption potential and the subsequent heat production of the resulting structures were monitored by means of infrared thermometry and compared with pristine commercially available MWCNTs. The functionalized silica microparticle substrates produced MWCNTs without any amorphous carbon but with increased structural defects, whereas their heat production performance as microwave absorbents was comparable to that of the pristine MWCNTs. Two-minute microwave irradiation of the SiO2@CNTs structures resulted in an increase in the material’s temperature from ambient temperature up to 173 °C. This research puts forward a new idea of charge modulation of MWCNTs and sheds light on an investigation for the development of bifunctional materials with improved properties with respect to efficient microwave absorbance.

Influence of osmolality on gastrointestinal fluid volume and drug absorption: potential impact on oral salt supplementation

Background The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is the most frequent cause of hyponatremia in patients with cerebrovascular disease, and is often treated with oral salt tablets. However, we have shown that osmolality-dependent variations in gastrointestinal (GI) fluid volume can alter the concentration of a poorly permeable drug in the GI tract, potentially affecting its absorption. Here, we examined the effect of ingestion of hyperosmotic solution (10% NaCl) on drug concentration and absorption in the GI tract. Methods The effects of osmolality on luminal fluid volume and drug absorption in rat intestine (jejunum, ileum and colon) were examined by means of an in situ closed loop method using fluorescein isothiocyanate-dextran 4000 (FD-4) and atenolol. In vivo absorption in rats was determined by measuring the plasma concentration after oral administration of the test compounds dissolved in purified water or hyperosmotic solution (10% NaCl). Results Administration of hyperosmotic solution directly into the GI tract significantly increased the GI fluid volume, owing to secretion of water into the lumen. After administration in hyperosmotic solution, the luminal concentration of non-permeable FD-4 was significantly lower than the initial dosing concentration, whereas after administration in purified water, the luminal concentration exceeded the initial concentration. The fraction absorbed of atenolol was markedly lower after administration in hyperosmotic solution than after administration in purified water. An in vivo pharmacokinetic study in rats was consistent with these findings. Conclusions Administration of hyperosmotic NaCl solution increased GI fluid volume and reduced the plasma level of orally administered atenolol. This may imply that oral salt tablets used to treat hyponatremia in SIADH patients could decrease the intestinal absorption of concomitantly administered drugs, resulting in lower plasma exposure.

A Comprehensive Review on the Applications of Exosomes and Liposomes in Regenerative Medicine and Tissue Engineering

Tissue engineering and regenerative medicine are generally concerned with reconstructing cells, tissues, or organs to restore typical biological characteristics. Liposomes are round vesicles with a hydrophilic center and bilayers of amphiphiles which are the most influential family of nanomedicine. Liposomes have extensive research, engineering, and medicine uses, particularly in a drug delivery system, genes, and vaccines for treatments. Exosomes are extracellular vesicles (EVs) that carry various biomolecular cargos such as miRNA, mRNA, DNA, and proteins. As exosomal cargo changes with adjustments in parent cells and position, research of exosomal cargo constituents provides a rare chance for sicknesses prognosis and care. Exosomes have a more substantial degree of bioactivity and immunogenicity than liposomes as they are distinctly chiefly formed by cells, which improves their steadiness in the bloodstream, and enhances their absorption potential and medicinal effectiveness in vitro and in vivo. In this review, the crucial challenges of exosome and liposome science and their functions in disease improvement and therapeutic applications in tissue engineering and regenerative medicine strategies are prominently highlighted.

Potential Risk Related To The Reuse of Faecal Sludge In Agriculture: Proposal For An Ecological Treatment Method Based On Active Charcoal

This study is aimed at highlighting the risks associated with the reuse of faecal sludge and proposed a sustainable treatment method. The sampling consisted of collecting samples of faecal sludge in 5L of sterilized containers and then transporting to the laboratory in a refrigerated chamber for the determination of helminth eggs using standard protocols. The experimental device consisted of two replicates, one test and one control. The test samples received active charcoal at different concentrations (C1, C2, C3, C4, C5, C6). The physico-chemical parameters were measured before and after treatment. The samples were then observed under the optical microscope at the 40X objective for morphological identifications. Molecular analysis was carried out using the Polymerase Chain Reaction technique. The viability of the eggs were determined using incubation and staining techniques. Analyses showed that the sludge used for irrigation contained eggs and larvae of 6 helminth species (S. stercoralis, A. duodenale, N. americanus, T. trichiuria, H. nana and Ascaris spp.) with viability percentages ranging from 57.72% to 74.46%. Treatment with active charcoal allowed significant adsorption of these parasites with yields ranging from 95 to 100%. In addition, the carbon used has favoured the alkaline stabilisation of the medium, which increases its absorption potential. It can therefore be used in the treatment of sludge because, unlike other chemical disinfectants, it does not present any toxic effects.

Role of Engineered Carbon Nanoparticles (CNPs) in Promoting Growth and Metabolism of Vigna radiata (L.) Wilczek: Insights into the Biochemical and Physiological Responses

Despite the documented significance of carbon-based nanomaterials (CNMs) in plant development, the knowledge of the impact of carbon nanoparticles (CNPs) dosage on physiological responses of crop plants is still scarce. Hence, the present study investigates the concentration-dependent impact of CNPs on the morphology and physiology of Vigna radiata. Crop seedlings were subjected to CNPs at varying concentrations (25 to 200 µM) in hydroponic medium for 96 h to evaluate various physiological parameters. CNPs at an intermediate concentration (100 to 150 µM) favor the growth of crops by increasing the total chlorophyll content (1.9-fold), protein content (1.14-fold) and plant biomass (fresh weight: 1.2-fold, dry weight: 1.14-fold). The highest activity of antioxidants (SOD, GOPX, APX and proline) was also recorded at these concentrations, which indicates a decline in ROS level at 100 µM. At the highest CNPs treatment (200 µM), aggregation of CNPs was observed more on the root surface and accumulated in higher concentrations in the plant tissues, which limits the absorption and translocation of nutrients to plants, and hence, at these concentrations, the oxidative damage imposed by CNPs is evaded with the rise in activity of antioxidants. These findings show the importance of CNPs as nano-fertilizers that not only improve plant growth by their slow and controlled release of nutrients, but also enhance the stress-tolerant and phytoremediation efficiency of plants in the polluted environment due to their enormous absorption potential.

Ultra-High Frequency Photoacoustic Microscopy: From Organelles to Organisms

This dissertation describes novel signal analysis and imaging techniques for ultrahigh frequency (UHF, over 100 MHz) Photoacoustic Microscopy (PAM). New approaches for extracting information pertaining to object structure and scale are described, and novel sensing techniques and contrast mechanisms for imaging biological samples ranging from single cells to small organisms are presented. In the first section, I describe a methodology for assessing the structure of biological cells using UHF-PAM. The power spectra of ultrasound (US) pulses backscattered from MCF-7 cells, and photoacoustic (PA) waves emitted from their dyed nuclei were fit to analytical solutions to determine cell and nucleus diameter, respectively. The measured cell diameters (15.5±1.8 μm) and nucleus diameters (12±1.3 μm) were used to calculate the mean cell nucleus-to-cytoplasm ratio (1.9±1.0). Good agreement was observed between UHF-PAM measured values and literature. In the second section, I present a novel technique for PA image reconstruction that utilizes unique features in the PA power spectra as a source of contrast. The technique, termed F-Mode, provides a means for differentiating between objects of different scale that surpasses the capabilities of conventional reconstruction approaches. The ability of F-Mode to selectively accentuate absorbers of different size was demonstrated using experimental phantoms containing microspheres and cylindrical vessels, as well as in individual biological cells and live zebrafish larvae. Finally, I developed a new sensing technique, termed Photoacoustic Radiometry (PAR). Unlike PAM, which depicts optical absorption, PAR images depict the optical attenuation properties of the imaged object. It was demonstrated that PAR can be used to image transparent samples which generate no PA signals, and that simultaneous triplex PAR/PA/US imaging could be realized using our approach. Simultaneous PAR/PA imaging of biological cells, as well as zebrafish larvae in vivo, was also demonstrated. UHF-PAM provided excellent visualization of vascular organization in the larval trunk and head. The simultaneously acquired PAR images depicted anatomical structure (e.g. the notochord, muscle segments) not visible in PAM due to insufficient optical absorption. Potential areas of application for the new UHF-PAM techniques described in this dissertation include detection of cancer cells in blood samples, and investigation of tumour growth and metastasis. (6 zipped .mp4 files) https://digital.library.ryerson.ca/islandora/object/RULA:8618/datastream/Movies_Moore_mp4/view

Ultra-High Frequency Photoacoustic Microscopy: From Organelles to Organisms

This dissertation describes novel signal analysis and imaging techniques for ultrahigh frequency (UHF, over 100 MHz) Photoacoustic Microscopy (PAM). New approaches for extracting information pertaining to object structure and scale are described, and novel sensing techniques and contrast mechanisms for imaging biological samples ranging from single cells to small organisms are presented. In the first section, I describe a methodology for assessing the structure of biological cells using UHF-PAM. The power spectra of ultrasound (US) pulses backscattered from MCF-7 cells, and photoacoustic (PA) waves emitted from their dyed nuclei were fit to analytical solutions to determine cell and nucleus diameter, respectively. The measured cell diameters (15.5±1.8 μm) and nucleus diameters (12±1.3 μm) were used to calculate the mean cell nucleus-to-cytoplasm ratio (1.9±1.0). Good agreement was observed between UHF-PAM measured values and literature. In the second section, I present a novel technique for PA image reconstruction that utilizes unique features in the PA power spectra as a source of contrast. The technique, termed F-Mode, provides a means for differentiating between objects of different scale that surpasses the capabilities of conventional reconstruction approaches. The ability of F-Mode to selectively accentuate absorbers of different size was demonstrated using experimental phantoms containing microspheres and cylindrical vessels, as well as in individual biological cells and live zebrafish larvae. Finally, I developed a new sensing technique, termed Photoacoustic Radiometry (PAR). Unlike PAM, which depicts optical absorption, PAR images depict the optical attenuation properties of the imaged object. It was demonstrated that PAR can be used to image transparent samples which generate no PA signals, and that simultaneous triplex PAR/PA/US imaging could be realized using our approach. Simultaneous PAR/PA imaging of biological cells, as well as zebrafish larvae in vivo, was also demonstrated. UHF-PAM provided excellent visualization of vascular organization in the larval trunk and head. The simultaneously acquired PAR images depicted anatomical structure (e.g. the notochord, muscle segments) not visible in PAM due to insufficient optical absorption. Potential areas of application for the new UHF-PAM techniques described in this dissertation include detection of cancer cells in blood samples, and investigation of tumour growth and metastasis. (6 zipped .mp4 files) https://digital.library.ryerson.ca/islandora/object/RULA:8618/datastream/Movies_Moore_mp4/view

Effect of Pre-Wetting Recycled Mortar Aggregate on the Mechanical Properties of Masonry Mortar

In this research we evaluated the use of recycled fine mortar aggregate (RFMA) as a fine aggregate for new masonry mortar creation. The pre-wetting effect on the aggregate before creating the mixture was analyzed as a method to reduce its absorption potential. A control mixture of conventional mortar and two groups of recycled mortars were designed with a partial replacement of natural sand by RFMA (pre-wetted and not pre-wetted) performed in different proportions. The results established that the pre-wetting process allows a reduction in the amount of water required during the creation of new mixtures, regulating the water/cement (W/C) ratio and improving the properties of recycled mortars such as air content, fresh and hardened densities, and compressive and adhesive strength for all substitution levels. Mortar made with a 20% substitution and pre-wetted until it was at 67% of its absorption capacity displayed adhesive values higher than the ones shown by the reference mortar. The pre-wetting process proves to be an easy performance technique; it is inexpensive, environmentally friendly, and the most valuable fact is that specialized equipment is not necessarily needed. This process is the most profitable option for improving RFMA exploitation and reuse.

Detection of absorbing aerosols from ground based observations of scattered sun light

<p>Absorption of solar radiation by atmospheric aerosols is an important heat source in the atmosphere. The absorption potential by aerosols (usually quantified by the co single scattering albedo) can vary strongly, depending on the aerosol composition. The absorption potential can be captured by in-situ sample analyses or retrieved by remote sensing techniques (e.g. by sun/sky photometry). For a global view, advanced satellite sensors with polarization and especially multi-viewing would be required (e.g. 3MI). However, sensor data at different UV wavelengths (e.g. TOMS) already inform qualitatively on the presence of (elevated) absorbing aerosol (i.e. from mineral dust, wildfires) via the so-called UV absorbing aerosol index (UVAI).</p><p>In this study, we propose an UVAI similar approach for ground-based observations of scattered sun light. We first performed radiative transfer simulations. Based on these simulations we found that absorbing aerosols can indeed be identified from ground-based measurements. We could in particular show that the detection of absorbing aerosols is possible in the presence of clouds (except optical very thick clouds), which will be of special importance, because existing remote sensing measurements of the aerosol absorption are only possible for clear sky conditions.</p><p>We also derived the UVAI from ground based measurements during a ship cruise in April and May 2019 over the tropical Atlantic. Clearly enhanced values of the UVAI could be detected when the ship crossed air masses which were contaminated by desert dust aerosols from the Sahara.</p><p>We present these early results and discuss possible future improvements.</p>