Suhrtherkelsen0742
The degradation pathways of highly active [Cp*Ir(κ2 -N,N-R-pica)Cl] catalysts (pica=picolinamidate; 1 R=H, 2 R=Me) for formic acid (FA) dehydrogenation were investigated by NMR spectroscopy and DFT calculations. Under acidic conditions (1 equiv. of HNO3 ), 2 undergoes partial protonation of the amide moiety, inducing rapid κ2 -N,N to κ2 -N,O ligand isomerization. Consistently, DFT modeling on the simpler complex 1 showed that the κ2 -N,N key intermediate of FA dehydrogenation (INH ), bearing a N-protonated pica, can easily transform into the κ2 -N,O analogue (INH2 ; ΔG≠ ≈11 kcal mol-1 , ΔG ≈-5 kcal mol-1 ). Intramolecular hydrogen liberation from INH2 is predicted to be rather prohibitive (ΔG≠ ≈26 kcal mol-1 , ΔG≈23 kcal mol-1 ), indicating that FA dehydrogenation should involve mostly κ2 -N,N intermediates, at least at relatively high pH. Under FA dehydrogenation conditions, 2 was progressively consumed, and the vast majority of the Ir centers (58 %) were eventually found in the form of Cp*-complexes with a pyridine-amine ligand. This likely derived from hydrogenation of the pyridine-carboxiamide via a hemiaminal intermediate, which could also be detected. Clear evidence for ligand hydrogenation being the main degradation pathway also for 1 was obtained, as further confirmed by spectroscopic and catalytic tests on the independently synthesized degradation product 1 c. DFT calculations confirmed that this side reaction is kinetically and thermodynamically accessible.
The fetal pillow has been suggested to reduce maternal trauma and fetal adverse outcomes when used to disimpact the fetal head at full dilatation cesarean section.
We performed a retrospective cohort study of the use of the fetal pillow device at full dilatation cesarean section between September 2014 and March 2018 at Liverpool Women's Hospital, a large UK teaching hospital.
There were 471 cases of full dilatation cesarean section during the study period and 391 were included for the analysis; 170 used the fetal pillow and 221 were delivered without. We did not demonstrate any benefit in the significant maternal outcomes of estimated blood loss >1000mL or >1500mL, need for blood transfusion, or duration of hospital stay, from the use of the fetal pillow. We did not demonstrate any improvement in fetal outcome following use of the fetal pillow for arterial pH <7.1, Apgar score <7 at 5minutes or admission to the neonatal unit. For deliveries undertaken at or below the level of the ischial spiore more widespread use.
During vascular surgery, restricted red-cell transfusion reduces frontal lobe oxygen (ScO
) saturation as determined by near-infrared spectroscopy. We evaluated whether inadequate increase in cardiac output (CO) following haemodilution explains reduction in ScO
.
This is a post-hoc analysis of data from the Transfusion in Vascular surgery (TV) Trial where patients were randomized on haemoglobin drop below 9.7g/dL to red-cell transfusion at haemoglobin below 8.0 (low-trigger) vs 9.7g/dL (high-trigger). Fluid administration was guided by optimizing stroke volume. We compared mean intraoperative levels of CO, haemoglobin, oxygen delivery, and CO at nadir ScO
with linear regression adjusted for age, operation type and baseline. Data for 46 patients randomized before end of surgery were included for analysis.
The low-trigger resulted in a 7.1% lower mean intraoperative haemoglobin level (mean difference, -0.74g/dL; P<.001) and reduced volume of red-cell transfused (median [inter-quartile range], 0 [0-300] vs 450mL [300-675]; P<.001) compared with the high-trigger group. Mean CO during surgery was numerically 7.3% higher in the low-trigger compared with the high-trigger group (mean difference, 0.36 L/min; 95% confidence interval (CI.95), -0.05 to 0.78; P=.092; n=42). At the nadir ScO
-level, CO was 11.9% higher in the low-trigger group (mean difference, 0.58 L/min; CI.95, 0.10-1.07; P=.024). No difference in oxygen delivery was detected between trial groups (MD, 1.39 dL
/min; CI.95, -6.16 to 8.93; P=.721).
Vascular surgical patients exposed to restrictive RBC transfusion elicit the expected increase in CO making it unlikely that their potentially limited cardiac capacity explains the associated ScO
decrease.
Vascular surgical patients exposed to restrictive RBC transfusion elicit the expected increase in CO making it unlikely that their potentially limited cardiac capacity explains the associated ScO2 decrease.
To compare marginal bone level changes around immediately placed and immediately provisionalized implants with immediately placed and delayed provisionalized implants in the aesthetic region after five years of function.
Forty patients with a failing tooth in the maxillary anterior region were randomly assigned immediate implant placement with immediate (Group A n=20) or delayed (Group B n=20) provisionalization. Definitive crown placement occurred three months after provisionalization. The primary outcomes were changes in marginal bone level. In addition, survival rates, buccal bone thickness, soft peri-implant tissues, aesthetics and patient-reported outcomes were assessed.
After 5years, the mean mesial and distal marginal bone level changes were 0.71±0.68mm and 0.71±0.71mm, respectively, in group A and 0.49±0.52mm and 0.54±0.64mm, respectively, in group B; the difference between the groups was not significant (p=.305 and p=.477, respectively). Implant and restoration survivals were 100%. No clinically relevant differences in buccal bone thickness or in mid-facial peri-implant mucosal level, aesthetic and patient outcomes were observed.
The mean marginal bone level changes following immediate implant placement and provisionalization were comparable with immediate implant placement and delayed provisionalization. (www.isrctn.com ISRCTN57251089 and www.trialregister.nl NL8255).
The mean marginal bone level changes following immediate implant placement and provisionalization were comparable with immediate implant placement and delayed provisionalization. SN38 (www.isrctn.com ISRCTN57251089 and www.trialregister.nl NL8255).
