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In order to contribute with experimental evidence that could help to achieve a better understanding of the field for future regulation, in the present work, the biocompatibility of commercial P25TiO2NPs (one type of TiO2NPs used in sunscreen formulations) and two novel functionalized P25TiO2NPs were evaluated under solar simulated irradiation. White light, generated by red, blue, and yellow LEDs, together with UV ones, was chosen to simulate the solar spectra. Functionalization of TiO2NPs was made with antioxidant vitamins in order to prevent the expected photo-initiated ROS production when nanoparticles are exposed to the simulated solar spectra. Vitamin B2 (riboflavin) and vitamin C were chosen to carry out the functionalization because they are water-soluble, low-cost, and are a constitutive part of biological processes. In addition, it is known that both have the potential to prevent macromolecular oxidation by ROS [23][24][25][26].

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{随机栏目} 2025-08-15 01:37 1719
  • Different dermal cell types have been reported to differ in their sensitivity to nano-sized TiO2 . Kiss et al. exposed human keratinocytes (HaCaT), human dermal fibroblast cells, sebaceous gland cells (SZ95) and primary human melanocytes to 9 nm-sized TiO2 particles at concentrations from 0.15 to 15 μg/cm2 for up to 4 days. The particles were detected in the cytoplasm and perinuclear region in fibroblasts and melanocytes, but not in kerati-nocytes or sebaceous cells. The uptake was associated with an increase in the intracellular Ca2+ concentration. A dose- and time-dependent decrease in cell proliferation was evident in all cell types, whereas in fibroblasts an increase in cell death via apoptosis has also been observed. Anatase TiO2 in 20–100 nm-sized form has been shown to be cytotoxic in mouse L929 fibroblasts. The decrease in cell viability was associated with an increase in the production of ROS and the depletion of glutathione. The particles were internalized and detected within lysosomes. In human keratinocytes exposed for 24 h to non-illuminated, 7 nm-sized anatase TiO2, a cluster analysis of the gene expression revealed that genes involved in the “inflammatory response” and “cell adhesion”, but not those involved in “oxidative stress” and “apoptosis”, were up-regulated. The results suggest that non-illuminated TiO2 particles have no significant impact on ROS-associated oxidative damage, but affect the cell-matrix adhesion in keratinocytes in extracellular matrix remodelling. In human keratinocytes, Kocbek et al. investigated the adverse effects of 25 nm-sized anatase TiO2 (5 and 10 μg/ml) after 3 months of exposure and found no changes in the cell growth and morphology, mitochondrial function and cell cycle distribution. The only change was a larger number of nanotubular intracellular connections in TiO2-exposed cells compared to non-exposed cells. Although the authors proposed that this change may indicate a cellular transformation, the significance of this finding is not clear. On the other hand, Dunford et al. studied the genotoxicity of UV-irradiated TiO2 extracted from sunscreen lotions, and reported severe damage to plasmid and nuclear DNA in human fibroblasts. Manitol (antioxidant) prevented DNA damage, implying that the genotoxicity was mediated by ROS.

    {随机栏目} 2025-08-15 01:13 2760
  • Grid covers are the structural framework that supports the ceiling tiles in a drop ceiling system. Typically made from metal, these grid systems create a suspended framework that holds ceiling tiles in place. The grid consists of main runners, cross tees, and wall angles, which work together to distribute the weight of the tiles evenly and maintain their integrity over time. Grid covers can also serve aesthetic purposes, adding a finished look to a space while allowing for easy access to above-ceiling utilities.


  • A ceiling hatch is a practical addition to any home, providing convenience and increasing space utilization. By choosing a high-quality product from Bunnings, you can enjoy the benefits of easy access to your roof or attic. Always consider your specific needs and consult with professionals if necessary, ensuring a successful installation that enhances your home’s functionality. Whether for maintenance, storage, or energy efficiency, investing in a ceiling hatch is a decision that can make a significant difference to your living space.


  • 2. Convenience Having an access panel can save time and reduce the inconvenience associated with home repairs. Instead of cutting into drywall or other ceiling materials, the use of an access panel allows for quick and efficient access to necessary areas.


  • The Rise of Drop Ceiling Tees A Versatile Solution for Modern Spaces


  • One of the most compelling advantages of frameless access panels is their seamless integration into the ceiling design. Unlike traditional access panels that disrupt the uniformity of a ceiling with visible frames, frameless panels provide a clean and minimalist appearance. This feature is particularly advantageous in contemporary settings, where smooth lines and uncluttered surfaces are paramount. Available in various finishes and custom sizes, frameless panels can be painted or textured to match the surrounding ceiling, making them virtually invisible.


  • 1. Durability One of the most significant advantages of FRP ceiling grids is their durability. Unlike traditional materials like metal or wood, FRP is resistant to rust, rot, and chemical damage. This longevity not only reduces maintenance costs but also extends the lifespan of the ceiling system itself.


  • Typically measuring 600mm x 600mm, these access hatches are designed for standard ceiling tiles, fitting seamlessly into most ceiling grids. They can be manufactured from various materials, including steel, aluminum, and plastic, each offering different advantages in terms of durability and weight. A quality access hatch should be fire-rated, moisture-resistant, and insulated to prevent energy loss and condensation issues.


  • Applications of Main Tee Ceiling Grid


  • Watertight access panels are designed to create a barrier against water intrusion, making them suitable for installations in areas prone to moisture or where water exposure is a risk, such as bathrooms, kitchens, basements, and roofs. They are made from robust materials, often featuring seals and gaskets that ensure a tight fit when closed. This design helps prevent the infiltration of water, which can lead to costly damage, mold growth, and structural degradation over time.


  • Additionally, ceiling grid tiles contribute to energy efficiency. Many modern tiles are designed with thermal insulation properties, helping to maintain temperature control. By incorporating these tiles, homeowners and businesses can reduce energy consumption, leading to lower utility costs while minimizing their environmental impact.


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  • What is a Sheetrock Ceiling Access Panel?


  • 1. Acoustic Tiles One of the most common materials, acoustic tiles are designed to absorb sound, making them ideal for offices, schools, and other environments where noise reduction is essential. Typically made from mineral fiber or fiberglass, these tiles are lightweight, easy to install, and can be found in various designs and finishes, enhancing the aesthetic of the space.


  • Why Choose Bunnings for Your Ceiling Hatch Needs?


  • What is a Drywall Ceiling Access Panel?


  • Customization Options


  • 1. Purpose Understand what systems need to be accessed and how frequently. For example, if the area needs regular access for maintenance, a larger size may be warranted.

  • - Level
  • 3. Insulation If energy efficiency is a concern, opt for a ceiling hatch with good insulation. An insulated hatch will help maintain your home’s temperature, reducing heating and cooling costs.


  • When it comes to the installation of suspended ceiling access panels, several factors must be taken into account to ensure a successful integration with the ceiling system. First, it is crucial to choose the correct size and style of the panel to match the ceiling’s design and the intended use. The weight of the panel and the materials used for the ceiling must also be compatible to maintain structural integrity.


  • Installation and Maintenance


  • In addition to aesthetic customization, functionality also varies. Some access hatches are designed for general access, while others feature enhanced security measures for sensitive areas. Fire-rated hatches are available for use in areas needing compliance with fire safety regulations, providing not just access, but also protection and peace of mind.