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Immunocytochemical Detection Systems
Published in Lars-Inge Larsson, Immunocytochemistry: Theory and Practice, 2020
This theoretical physical reasoning has several practical implications for the construction of the microscope. The older generation of fluorescence microscopes made use of transmitted light. To prevent the transmitted light from reaching (and damaging) the eyes of the observer and obscuring the image, dark-field condensers were employed. Such condensers operate at different levels of quality with different objectives. Therefore, one major innovation in the field has been the introduction of epi-illumination systems, in which the objective simultaneously acts both in its original capacity and as a condenser to illuminate the specimen.175,274 In this way, only reflected exciting light and emitted light will re-enter the objective. The reflected exciting light will be removed by the dichroic mirrors and secondary filters of the system. A second major advance has been the introduction of immersion objectives of high numerical apertures also for low-magnification fluorescence work. In this way, the loss of emitted light by reflection (which is considerable with nonimmersion, low-power objectives of long operating distance) is nearly totally avoided. Purchase of a new fluorescence microscope without immersion objectives is not recommended. Such objectives are now available from the major microscopy firms.
Liver Microcirculation
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
Following anesthesia, the edge of a small laboratory animal (e.g., mouse or rat) is gently exteriorized through a 2-cm right subcostal incision and positioned over a window in a specially designed plexiglass stage. The window overlies a long-working distance condenser of a modified microscope (e.g., Leitz Panphot or Nikon TMD inverted microscope). The liver is further covered by a piece of Saran Wrap® fixed to a movable U-shaped frame. This construction limits movements induced by respiration and heart beat; however, it is flexible enough not to cause impairment of hepatic microcirculation. Homeostasis is achieved by continuous irrigation with Ringers’s solution and additional temperature control (37°C). Transillumination of the liver can be performed with monochromatic light (550–750 nm) from a prism monochrometer equipped with a Xenon lamp (Leitz, XBO-150). The microscope tube is positioned over the transilluminated area and microscopic images of the microvasculature allowed magnifications of 200 to 1350× using appropriate objectives of 8 to 100×. Optical images are recorded using a low-light video camera and video recording system (for further details see References 19, 67, and 68). A high-resolution Chalnicon camera (Hamamatsu) connected to an image processor incorporating analog enhancement (Hamamatsu Argus 100/VEC) leads to further improvement of the system.4
Water and hydration in the workplace *
Published in Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse, Routledge Handbook of Water and Health, 2015
While water can become contaminated in the community after weather-related events such as flooding, tornados, hurricanes, and the like, or accidental release of chemicals into groundwater or water supply, water may also become contaminated with bacteria, parasites, and chemicals in the workplace which can cause disease. Sources where temperatures allow bacteria to live include hot water tanks, cooling towers, and evaporative condensers of large air-conditioning systems, commonly found in hotels and large office buildings. Legionnaires’ disease, which first occurred in 1976 at a convention of the American Legion at a hotel in Philadelphia, is a prime example of inhaled aerosolized water contaminated with Legionella bacteria (CDC 2013c).
Myrothamnus flabellifolius Welw. (Myrothamnaceae) essential oil scavenges free radicals and inhibits carbohydrate-metabolizing enzymes in vitro
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Abdulwakeel Ayokun-nun Ajao, Fatai Oladunni Balogun, Saheed Sabiu, Anofi O. Tom Ashafa
The ground plant sample (120 g) was subjected to a hydrodistillation process based on British Pharmacopeia [13] specifications to obtain the oil. Briefly, 120 g of the plant sample was emptied into a round bottom flask (2 L capacity), followed by adding 0.9 L distilled water to ensure complete immersion of the sample. The flask connected to a Clevenger-type apparatus (with a condenser) was exposed to a 3-hr. heat supplied by a heating mantle (electric). The mixture (water and volatile oil vapor) was made to undergo the processes of evaporation, condensation, and distillation, thereafter, collected as two layers, left unperturbed for 30 min for proper separation (oil/water layers). The obtained MFEO was rid of possible retained water by dehydration with sodium sulfate and stored at 4ºC in an amber glass bottle until use.
Recent advances in freeze-drying: variables, cycle optimization, and innovative techniques
Published in Pharmaceutical Development and Technology, 2022
Mohammed M. Mehanna, Kawthar K. Abla
The conventional freeze-dryer consists of five main components: refrigerator unit, vacuum unit, control unit, product chamber or manifold, and the condenser. The refrigeration is employed to cool both; the shelves within the product chamber and to cool the condenser. The vacuum unit provides pressure for conducting the drying stages. The system is made up of a separate vacuum pump attached to the chamber and connected to an airtight condenser. The control system contains temperature and pressure sensors attaining to set up these critical values as required. The product chamber of the freeze-dryer is either a manifold with attached flasks or a chamber containing shelves where the product is placed and dried. The condenser aims to collect the vapor released by ice within the product, where the vapor condensed before returning into ice within the condenser itself. The accumulated ice is removed manually at the end of the drying stage. The condenser temperature is dictated by Tp and the product freezing point. The refrigeration system should keep the temperature of the condenser below the product temperature. Typically, the temperature of the condenser in the commercial freeze-dryer is about −65 °C (; Bisht and Iqbal 2018; Garcia-Amezquita et al. 2015).
Imaging and Differentiation of Retinal Ganglion Cells in Ex Vivo Experimental Optic Nerve Degeneration by Differential Interference Contrast Microscopy
Published in Current Eye Research, 2019
Juyeong Oh, Yu Jeong Kim, Youngho Cho, Subeen Park, Hyung Min Kim, Chulki Kim, Taikjin Lee, Seong Chan Jun, Ki Ho Park, Dae Yu Kim, Jae Hun Kim, Seok Hwan Kim
DIC microscopy is an imaging technique that utilizes beam interference for unstained and transparent specimens. (Figure 1) The front linear polarizer converts the unpolarized beam, the bandgap and wavelength of which are modified, into a 45°-polarized beam. The controlled beam meets the Wollaston prism, which separates the light wave into two directions with orthogonal polarization. The condenser refracts the orthogonal beams to illuminate the specimen, and pass through it with a small offset. When the orthogonal offset beams contact the transparent specimen, their velocities are different. Each beam experiences a different thickness and refractive index, which induce different optical path lengths. Thus, the beams contain gradient information, in the form of a phase shift, between the offset. For a transmission-type DIC microscopy, the second Wollaston prism and the second linear polarizer are located behind the specimen and attune the beams’ paths and polarizations. The resultant combined beam shows interference due to the phase difference. The bandpass filter is utilized to tune the wavelength (790 nm) and bandwidth (1.5 nm). A second condenser lens is aligned for Kohler illumination. Additionally, fluorescence microscopy is combined with DIC microscopy to confirm the RGCs in the identical area in the layer. To construct a reflection-type DIC, a beam splitter (50:50) was placed between the objective lens and the Wollaston prism. (Figure 1e)