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Benzylpenicillin (Penicillin G)
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Alasdair M. Geddes, Ian M. Gould, Jason A. Roberts, Jason A. Trubiano, M. Lindsay Grayson
To avoid the potential problems associated with continuous infusion, most clinicians prefer either intermittent i.v. injections or intermittent rapid infusions of high concentration Pen G solutions via a secondary i.v. bottle or a burette. Each dose can be dissolved in 10–20 ml of sterile water in a syringe, and this is injected directly into the i.v. tubing over a period of 5 minutes. Alternatively, the drug can be given via a pediatric burette that is incorporated in the i.v. set. When a dose of the drug is due, 20–30 ml of i.v. fluid is delivered into the burette to which a dissolved dose of Pen G is added; this concentrated drug solution is then infused over a period of 10–15 minutes. An added advantage of this method is that the burette filter removes a proportion of particulate matter, which is commonly present in the syringe when antibiotics are withdrawn from ampoules or vials. For babies and young children, i.v. infusion pumps that can deliver both i.v. fluids and antibiotics intermittently at a desired rate are advantageous (Leff and Roberts, 1981).
Methods in Physical Science: Feelings Don’t Matter
Published in David E. H. Jones, Why Are We Conscious?, 2017
Our senses were later scrutinized scientifically by Gustav Fechner. He wrote in 1860 that the smallest noticeable sensory difference is about 1 to 2 percent. Thus one might expect that sort of difference between different observers. This measurement is now part of sensory psychology as the Weber-Fechner law. In chemistry, it often crops up in consistent differences between analysts. Such differences probably arise from a set of consistent habits built up by each individual analyst, perhaps some personal way of making a filtration or of reading a burette. Hence the value of ‘standard samples’, which should give the same analysis even if analysed by different workers or at different times. This is a good example of the various tricks which experimentalists have evolved to overcome the problems which may arise where human observations differ worryingly. Another is the universal reliance on scientific instruments. We all have different ideas of the temperature, but the reading on a thermometer can be seen and agreed upon by everybody. We are each sensitive to electricity in our own way, but again, the reading on a voltmeter is objective. We may even differ about what we see, but a photograph can be shared by all observers. It is our good fortune that many essentially sporadic and unpredictable events, like those around cosmic rays, happen often enough for single experimental scientists to be able to study them when they occur. As a result, many of their individual reports may be built up into a useful understanding.
Oxygen Measurement
Published in Lara Wijayasiri, Kate McCombe, Paul Hatton, David Bogod, The Primary FRCA Structured Oral Examination Study Guide 1, 2017
Lara Wijayasiri, Kate McCombe, Paul Hatton, David Bogod
Haldane apparatus: This is utilised as an instrument for estimating the proportion of oxygen in expired gases.It consists of a burette containing a volume of gas.The gas is then exposed to a solution of pyrogallol (a powerful reducing agent able to absorb oxygen).The volume of the remaining gas is then measured.The reduction in gas volume indicates the quantity of oxygen absorbed by the pyrogallol.This system can also be used to measure CO2, but here potassium hydroxide solution is used instead of pyrogallol.
Gastroretentive bilayer film for sustained release of atorvastatin calcium and immediate release of amlodipine besylate: pharmaceutical, pharmacokinetic evaluation, and IVIVC
Published in Pharmaceutical Development and Technology, 2020
Amit Porwal, Harinath Dwivedi, Kamla Pathak
Modified Rosette Rice Test apparatus was used to perform in vitro drug release study (Gohel et al. 2004; Singh and Pathak 2016). The modified beaker was filled with 70 ml of phosphate buffer, pH 4.5 with 0.02% w/v Tween 80 into which the films were placed as shown in Figure 1. A pH of 4.5 was selected which represents the midvalue of fed state pH ranging from 2.5 to 6.5. The test was performed at 37 ± 0.5 °C and 75 rpm. From a burette, fresh dissolution medium was added at a flow rate of 2 ml/min. A 5 ml of sample was withdrawn at 0, 5, 10, 15, 20, and 25 min and filtered. To maintain the sink condition, an equal volume of fresh media was replaced immediately after withdrawing test sample into the beaker. The samples were diluted suitably and analyzed spectrophotometrically (UV 6300 Double beam Spectrophotometer) at 225 nm. All experiments were performed in triplicate.
Influence of doping chromium ions on the electrical properties of hydroxyapatite
Published in Egyptian Journal of Basic and Applied Sciences, 2020
Moustafa Ibrahim, Abdelfattah Dawood
Calcium phosphate powder was prepared by precipitation method as follows: 0.16 mol of calcium nitrate tetrahydrate [Ca(No3)2 · 4H2O] was dissolved in 1 l of de-ionized water and 0.096 mol of di-ammonium hydrogen ortho-phosphate [(NH4)2HPO4] to accomplish the Ca/P ratio at 1.67. The Cr-HA was prepared as follows: different amounts of chromium nitrate Cr (No3)2 · 9H2O [0.005, 0.01, 0.02, 0.03 mol] was dissolved in 1 l of de-ionized water with 0.16 mol of calcium nitrate tetrahydrate [Ca (No3)2 · 4H2O]. The pH was adjusted to about 10 by adding dilute NH4OH solution. A volume of 0.096 mol [(NH4)2HPO4] solution was fed from a burette (2–5 ml/min) into a stirred solution of 0.16 mol [Ca(No3)2 · 4H2O] heated to 60°C on a hot plate (at pH = 10). Then, the solution was aged and stirred at its boiling point for about 2 h in a sealed container. The pure and Cr-HA samples were obtained by sucking filtration and purified three times with de-ionized water. The product was then dried overnight at 100°C and powdered by grinding mill.
Prior exposure to nutritive and artificial sweeteners differentially alters the magnitude and persistence of sucrose-conditioned flavor preferences in BALB/c and C57BL/6 inbred mouse strains
Published in Nutritional Neuroscience, 2019
Sam LaMagna, Kerstin Olsson, Deena Warshaw, Gabriela Fazilov, Ben Iskhakov, Agata Buras, Richard J. Bodnar
At 4 weeks of age, the mice were individually housed in plastic cages (30 × 20 × 15 cm3) with stainless steel tops throughout the study and received burettes of sucrose (10%, 5 M, 5 F of each strain), saccharin (0.2%, 5 M, 5 F of each strain) or water (5 M, 5 F of each strain) solutions in their cages in addition to pre-weighed chow and water continuously for 4 weeks. The burettes were made by retrofitting a leur slip tip syringe (100 ml, 1 ml gradations), silicone sealant, a rubber cork, and a straight sipper tube (63 mm in length, 8 mm in width, Lab Products, Seaford, DE). The burette was built by removing and drilling a hole into the tip of the syringe, inserting the cork and sipper tube into the hole, and securing them with the sealant that also prevented leaking. The burette was firmly secured to the stainless steel top of the cage by a taut metal spring (100 mm) with clips at each end that affixed to the cage top (e.g.14,15,25). Body weights were measured before exposure, and at the end of each of the 4 weeks of adolescent exposure to the solutions. Burette, chow, and water intakes were measured twice each week, and weekly intakes were calculated. Because the animals were housed in their home cages with bedding to minimize stress, spillage of uneaten chow could not be assessed.