Assessment of lower urinarytract function
David M. Luesley, Mark D. Kilby in Obstetrics & Gynaecology, 2016
There are several different physical principles that can be utilised to provide an accurate assessment of flow. The following three methods are in common use. Gravimetric method. The rate of change of the weight of the voided urine in the collecting jug is converted into a flow rate (Fig. 94.3).Rotatingdisc method. A known amount of power is required to keep a rotating disc spinning at a constant rate. Voided fluid is directed onto the disc, increasing its inertia. The flow rate is proportional to the amount of extra power that is required to keep the disc spinning at a constant rate.Capacitance dipstick. A metal capacitor strip is attached to the side of the flowmeter. As urine accumulates in the container, the electrical capacitance of the dipstick changes and from this the rate of flow can be calculated. It should be noted that the environment in which the woman performs the flow rate recording will have a considerable influence on the results. It is important that every effort is made to make the patient feel as comfortable and relaxed as possible, and that privacy and dignity are maintained at all times.
Basic Urodynamic Tests: Uroflowmetry
Linda Cardozo, Staskin David in Textbook of Female Urology and Urogynecology - Two-Volume Set, 2017
The grAvimetric method: This technique operAtes by meAsuring the weight of the collected fluid or hydrostAtic pressure At the bAse of the collecting cylinder. In both cAses, the output signAl is proportionAl to the collected fluid mAss. GrAvimetric meters therefore meAsure AccumulAted mAss, And mAss flow rAte is obtAined by differentiAtion. nowAdAys, most of the uroflowmeters use this principle of uroflow meAsurement thAt is considered As the most precise meAsurement technique. The electronic dipstick method: The electricAl cApAcitAnce of A dipstick mounted in the collecting chAmber chAnges As urine AccumulAtes. The output signAl is proportionAl to the AccumulAted volume And the volumetric flow rAte is obtAined by differentiAtion. The rotAting disk method: The voided fluid is directed onto A rotAting disk, thereby increAsing the inertiA of the disk. The power required to keep the disk rotAting At A constAnt speed is proportionAl to the mAss flow rAte of the fluid. The AccumulAted mAss is obtAined by integrAtion.
Oxygen Consumption
Robert A. Greenwald in CRC Handbook of Methods for Oxygen Radical Research, 2018
For the standardized working conditions that we use (Vf = 2000 μℓ and 30°C), substitution of these numbers in the equation gives k = 0.901 × Vf + 0.052. Thus, it is only necessary to determine the volume of the flask/manometer assembly to the 150 mm mark (V1), from which Vg can be obtained as Vt − Vf. A variety of methods is available for the determination of Vt. In our experience, gravimetric calibration with mercury is the most accurate and, once the necessary skill has been acquired, it is not particularly time-consuming. A detailed description of the method would be lengthy to include here and the reader is directed to the definitive book on manometric techniques by Umbreit et al.1
Deriving control parameter settings from process models to control capsule fillers integrated into continuous manufacturing
Published in Drug Development and Industrial Pharmacy, 2019
Bernhard Wagner, Shea Fen Cheong, Thomas Brinz, Johannes Khinast
To include a control option into the system, a gravimetric scale and a process analytical technology sensor (PAT), [9] for active pharmaceutical ingredient (API) content detection may be added to the process (Figure 1). The sensors form the basis to control the capsule filling process. A gravimetric scale allows an inline weight measurement, and thus, each capsule’s weight is determined. A PAT sensor can detect the API concentration [10], which therefore can be used with the gravimetric weighing system to determine the amount of API inside the capsule. Nowadays, PAT sensors can be implemented in various locations of a process, e.g. on a tablet press [11–13], using either in-line, at-line, or on-line implementations. In a capsule filling process, online measurement can be used: capsules are separated after the filling process, and the API content can automatically be determined, e.g. via Raman transmission spectroscopy [14]. Other options are to measure the API content via near infrared (NIR) reflection spectroscopy from the surface of the open capsule, or to analyze the powder inside the bowl of the capsule filler.
Assessing variability of aerosols generated from e-Cigarettes
Published in Inhalation Toxicology, 2022
Darpan Das, Sarah-Marie Alam El Din, Jairus Pulczinski, Jana N. Mihalic, Rui Chen, Joseph Bressler, Ana M. Rule, Gurumurthy Ramachandran
Thus, aerosol dynamics make evaluation between studies done by different investigators using different devices hard to compare. It has been reported that puffing protocol (i.e. duration, frequency and volume), dilution air, and length of time measurement are important parameters that influence the particle dynamics of aerosols generated from e-cigarettes (Ingebrethsen et al. 2012; Mikheev et al. 2016, 2018). Similar observations were also reported by Ruprecht et al. 2014, where they found that nicotine-enriched e-cigarettes produced lower PM levels than similar nicotine-free e-cigarettes. Ruprecht et al. 2014 attributed this phenomenon to the change in the optical properties of the PM such as color, morphology and other physical and chemical parameters. Furthermore, the argument is not limited to optical instruments and may also be applicable to gravimetric measurements. The filter substrate media is not able to capture the semi-volatile aerosols that are present in the environment. Further, adding flavors increases the vapor pressure and thus increases the volatility. Hygroscopicity and volatility of aerosols generated from e-cigs contribute to large extent toward the variability (Ingebrethsen et al. 2012). PG:VG is the main constituent in the e-liquid as well as in aerosol droplet formed in the vaping process (Gillman et al. 2020). Aerosols are generated both in the particle phase as well as the vapor phase (Pankow et al. 2018). For the scope of the present study, aerosols were only measured for the particle phase.
Investigational topical anticholinergics in clinical development for the treatment of hyperhidrosis
Published in Expert Opinion on Investigational Drugs, 2021
Stamatios Gregoriou, Anna Campanati, Dimitrios Rigopoulos, Anna Maria Offidani, Alexandros Stratigos, George Kontochristoulos
SB is an ester analog of glycopyrrolate. SB follows the principles of retrometabolic drug design. A recent multicentric, double blind, placebo-controlled phase II trial compared three concentrations of 5%, 10%, 15% of SB gel applied once daily for 42 days in 227 patients with AH. A significantly higher percentage of participants in each SB group exhibited ≥1 and ≥2 points improvement in the Hyperhidrosis Disease Severity Measure-Axillary score (HDSM-Ax) vs the vehicle group. Gravimetry and HDSS also showed statistically significant improvement. Adverse events resulted in 12 participants discontinuing, the study and included dry eyes, dry mouth, blurred vision, mydriasis, urinary retention, constipation, as well as topical erythema, burning or itching sensation and dryness at the application site [12]. A Phase III with the 5% gel in 281 Japanese patients resulted in approval in Japan. Patients who achieved both HDSS of 1 or 2 and a 50% reduction in gravimetric weight of sweat at the end of 6 weeks were 44.0% in the SB group and 30.7% in the vehicle group. SB is contraindicated in patients with angle-closure glaucoma and in those with dysuria due to benign prostatic hyperplasia [13].
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