An example of goal-directed proof

We prove a non-trivial property of relations in a way that emphasises the creative process in its construction.Comment: 9 pages. Submitted for publicatio

Suppression of Liquid-Liquid Phase Separation and Aggregation of Antibodies by Modest Pressure Application

The high colloidal stability of antibody (immunoglobulin) solutions is important for pharmaceutical applications. Inert cosolutes, excipients, are generally used in therapeutic protein formulations to minimize physical instabilities, such as liquid-liquid phase separation (LLPS), aggregation and precipitation, which are often encountered during manufacturing and storage. Despite their widespread use, a detailed understanding of how excipients modulate the specific protein-protein interactions responsible for these instabilities is still lacking. In this work, we demonstrate the high sensitivity to pressure of globulin condensates as a suitable means to suppress LLPS and subsequent aggregation of concentrated antibody solutions. The addition of excipients has only a minor effect. The high pressure sensitivity observed is due to the fact that these flexible Y-shaped molecules create a considerable amount of void volume in the condensed phase, leading to an overall decrease in the volume of the system upon dissociation of the droplet phase by pressure already at a few tens of to hundred bar. Moreover, we show that immunoglobulin molecules themselves are highly resistant to unfolding under pressure, and can even sustain pressures up to about 6 kbar without conformational changes. This implies that immunoglobulins are resistant to the pressure treatment of foods, such as milk, in high-pressure food-processing technologies, thereby preserving their immunological activity

Influence of suspension viscosity on Brownian relaxation of filler particles

Brownian relaxation caused by Brownian movement of particles in suspensions can macroscopically be probed by small-amplitude oscillatory shear experiments. Phenomenological considerations suggest a direct proportionality between suspension viscosity and Brownian relaxation times. To verify this relation experimentally, a set of nanocomposite suspensions with viscosities varying over five decades is presented. The suspensions are chosen in a way to ensure that particle-particle interactions and average particle-particle distances are identical so that they can be used as a model system to study the mere influence of suspension viscosity on Brownian relaxation. The suggested linear relationship between suspension viscosity and Brownian relaxation time can be confirmed. Moreover, a verification of a recently introduced characteristic timescale for Brownian relaxation is presented

Postpartum Blood Loss in Women Treated for Intrahepatic Cholestasis of Pregnancy

OBJECTIVE To evaluate postpartum blood loss in women with treated intrahepatic cholestasis of pregnancy. METHODS In a retrospective case-control study, 15,083 deliveries including 348 women with intrahepatic cholestasis of pregnancy (2.3%) were analyzed from 2004 to 2014. To adjust for differences in baseline characteristics, a propensity analysis was performed and women in the control group were matched to the women in the intrahepatic cholestasis of pregnancy group in a 5:1 ratio. Blood loss was analyzed by estimated blood loss and Δ hemoglobin (Hb, difference between prepartum and postpartum Hb). A subgroup analysis regarding severity of intrahepatic cholestasis of pregnancy based on maximum bile acid level (mild [less than 40 micromoles/L], moderate [40-99 micromoles/L], and severe intrahepatic cholestasis of pregnancy [100 micromoles/L or greater]) was performed. Differences in estimated blood loss, ΔHb, and meconium staining between subgroups were analyzed. A Spearman rank correlation was performed to evaluate the association of bile acid levels and blood loss within subgroups. RESULTS Estimated blood loss (median 400 [300-600] mL compared with 400 [300-600] mL, P=.22), ΔHb (14.0 [5.0-22.0] compared with 12.0 [4.0-21.0] g/L, P=.09), meconium staining (14.5% compared with 11.4%, P=.12), and number of stillbirths after 26 weeks of gestation (0.6% compared with 1.8%, P=.10) were not significantly different in the study compared with the control group. In moderate and severe intrahepatic cholestasis of pregnancy, meconium staining was observed significantly more often compared with that in a control group (23.0% and 32.3% compared with 11.4%, P<.01). There was no correlation between estimated blood loss or ΔHb and severity of intrahepatic cholestasis of pregnancy. CONCLUSIONS In our cohort of women with intrahepatic cholestasis of pregnancy who are treated with ursodeoxycholic acid and have planned delivery (induction of labor or planned cesarean delivery) at 38 weeks of gestation, no differences in postpartum blood loss were seen