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Evaluation of standard methods for the enumeration of coliforms from drinking waters
Published in Cara Gleeson, Nick Gray, The Coliform Index and Waterborne Disease, 1996
The petri dishes and membranes should then be placed in an airtight container to prevent drying out. Alternatively, a polythene bag may be used, provided it is carefully folded over, tied and sealed.
Overview of Recent Trends in Stem Cell Bioprocessing
Published in V. Sivasubramanian, Bioprocess Engineering for a Green Environment, 2018
M. Jerold, V. Sivasubramanian, K. Vasantharaj, C. Vigneshwaran
Petri dishes are commonly used for culturing various cell lines of adherent cells, feeder cells, ESCs, and so on. Figure 15.4 shows the formation of differentiated ESCs in monolayer in a plated disc. The starter cells are submerged in culture medium containing essential nutrients and signaling-inducing molecules for the expansion of cells. A two-dimensional approach is used to culture the cells. However, the stem cells grow in a dense colony with a distinct bordered pattern. During the expansion stage, the cells’ size and shape enlarge, and they merge with the neighboring colonies on the plates (Thomson et al., 1998; Takahashi et al., 2007). Later, the cells are transferred into the desired medium based on need, either expansion or differentiation. When the cells are at the confluent stage, it is allowed for expansion with defined growth factors preferred. In the culturing of ESCs, a day-old culture was trypsinized and followed by culturing on a plate coated (100 mm) with fibronectin 50 µg/mL. In each transfer, an average of 107 cells were maintained to obtain a uniform monolayer of ESCs. Figure 15.5 shows the culturing of ESCs on a two-dimensional (2D) plate. There are various drawbacks to (2D) plate cultures, for example, they cannot provide suitable conditions for culturing an organism’s specialized cells. In addition, there is a lack of three-dimensional (3D) cell–cell and cell–matrix interactions, temporal gradients of biochemical and physical signals, and systemic regulation, including cross-talk between different organ systems (Kaplan et al., 2005; Vunjak-Novakovic et al., 2005).
Spinel ferrite of MnFe2O4 synthesized in Piper betle Linn extract media and its application as photocatalysts and antibacterial
Published in Journal of Dispersion Science and Technology, 2021
Rahmayeni Rahmayeni, Yenti Oktavia, Yeni Stiadi, Syukri Arief, Zulhadjri Zulhadjri
Antibacterial activity of the samples was screened against pathogen bacteria, i.e. Staphylococcus aureus and Escherichia coli as following procedure[10,27]: Nutrient agar (NA) media was prepared by dissolving an amount of agar in distilled water, boiled, and sterilized in an autoclave at 121 °C for 20 min, and then cooled until 45 °C. Petri dishes for antibacterial assay were sterilized in an autoclave. Bacterial was subcultured in 5 mL of sterile distilled water for overnight. A total of 0.1 mL of the bacteria were added to 20 mL of NA media and homogenized. NA media that already contains the bacteria was poured into a sterile petri dish and allowed to solid. The synthesized MnFe2O4 samples were inserted into wells that had been made on the NA media. Amoxicillin as a positive control and water as negative control were also entered into two other wells. The inhibition zone of the samples was measured after incubation at 37 °C for 24 h.
PEGylated microemulsion for dexamethasone delivery to posterior segment of eye
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Sterility, isotonicity and non-irritancy are requisite properties of any typical topical ocular formulation. Same qualities were also expected from topical MEs. For evaluation of sterility, Luria agar broth was prepared under sterile conditions, plated on Petri dishes and allowed them to settle for some time in biosafety cabinet class II. Upon settling, 1 mL of formulations along with saline solution (0.9% NaCl) (dispensed under aseptic condition) were spread over its surface in individual Petri dish. These Petri dishes were sealed and kept inside incubator set at 37 °C. At definite time intervals, these Petri dishes were observed for any kind of contamination and bacterial/fungal growth. The absence of any contamination would confirm the sterility of developed formulations [44].
Photocatalytic degradation of phenazopyridine contaminant in soil with direct solar light
Published in Environmental Technology, 2019
Ahed Zyoud, Maysaa Ateeq, Muath H. Helal, Samer H. Zyoud, Hikmat S. Hilal
A UV-1601 spectrophotometer was used for solid-state electronic absorption spectra. A Perkin-Elmer LS50 Spectrophotometer was used for photoluminescence (PL). A Philips XRD XPERTPRO diffracto-meter with Cu Kα radiation (λ = 1.5418 Å) located in ICMCB, University of Bordeaux was used for X-ray diffraction (XRD) pattern measurements. A Clarus 500 Perkin-Elmer Gas Ghromatograph/Clarus 560D Mass Spectrometer system, equipped with a 30 m long ELite-5 (crossbond 5% diphenyl-95% dimethyl polysiloxane) column was used for GLC-MS analysis. The column oven starting temperature was set at 50°C for 10 min, and raised to 100°C (ramp rate 2°C/min) for additional 20 min. An ICE3000 Thermoscientific Atomic Absorption Spectrophotometer equipped with a zinc lamp was used for atomic absorption spectroscopy (AAS). Petri dishes, 9 cm in diameter, were used as reaction containers. The container was covered with a glass plate (10 × 10 cm2, 0.2 cm thick) to keep reaction mixture wet. The type of glass plate was carefully chosen with high transparency to both visible and UV radiations, like other plastic covers commonly used in agriculture. The plate was 90% transparent to incident light with λ = 300 nm and longer as confirmed by testing the transmittance spectrophotometry, Figure 2.