Pulse-chromatographic N2O titration of the copper surface area on CuZnOMeOx catalysts in connection with their hydrogen adsorption

1992 ◽  
Vol 73 (2) ◽  
pp. 203-214 ◽  
Author(s):  
H. Berndt ◽  
V. Briehn ◽  
S. Evert
2019 ◽  
Vol 45 (4) ◽  
pp. 263-268 ◽  
Author(s):  
Hannat Akintomide ◽  
Pam Barnes ◽  
Nataliya Brima ◽  
Diana Mansour

BackgroundT-shaped intrauterine devices (IUDs) with a copper surface area of 380 mm2 and copper bands on the transverse arms are the most effective types of copper-containing IUDs. A small-sized ‘gold standard’ IUD is available but there has been little research to compare the effects of this small-sized IUD to its standard-sized counterpart.AimTo determine discontinuation rates and reasons for discontinuation at 1 year of the small-sized Mini TT380 Slimline IUD compared with the standard-sized TT380 Slimline.MethodsThe clinical records of women fitted with Mini TT380 Slimline (‘mini’) IUDs were compared with those of women fitted with standard-sized TT380 Slimline (‘standard’) IUDs over a 3-year period (2013–2016).ResultsClinical records were available for 67 women fitted with a mini IUD (mean age 23 years, 64% nulliparous) and 63 women fitted with a standard IUD (mean age 25 years, 39% nulliparous). At 1 year, twice as many standard IUD users (32%, n=20) had discontinued their IUD use compared with mini IUD users (15%, n=10). Complaints of pain and bleeding were more than double (70%, n=14) in those women who discontinued standard IUD use compared with those who discontinued using the mini IUD (30%, n=3). These differences were statistically significant and were unrelated to parity.ConclusionsMore women using a standard-sized ‘gold standard’ IUD rather than its smaller counterpart complained of pain and bleeding, leading to higher discontinuation at 1 year. More research on the association between size and discontinuation of these IUDs is needed.


1989 ◽  
Vol 54 (6) ◽  
pp. 1514-1529 ◽  
Author(s):  
Bohumír Dvořák ◽  
Antonín Hudec ◽  
Josef Pašek

The method for determination of specific copper area by decompositive adsorption of N2O has been investigated using pulse chromatographic technique. The reaction is accompanied by activated adsorption of oxygen. The amount of oxygen adsorbed depends linearly upon the temperature in the range of -20 to +90 °C. The existence of an oxygen monolayer in the temperature range from 90 to 120 °C has been proved. On the surface, the Cu:O ratio is equal to 2. The rate of decompositive N2O adsorption is very high. The weakly bonded oxygen can be desorbed at 100 °C into a stream of inert gas and the rate of oxygen desorption depends on the temperature of decompositive N2O adsorption. An improved procedure for measuring copper surface area by pulse chromatographic technique have been suggested.


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