Analytical method for reconstructing the stress on a spherical particle from its surface deformation.

The mechanical forces that cells experience from the tissue surrounding them are crucial for their behavior and development. Experimental studies of such mechanical forces require a method for measuring them. A widely used approach in this context is bead deformation analysis, where spherical particles are embedded into the tissue. The deformation of the particles then allows to reconstruct the mechanical stress acting on them. Existing approaches for this reconstruction are either very time-consuming or not sufficiently general. In this article, we present an analytical approach to this problem based on an expansion in solid spherical harmonics that allows us to find the complete stress tensor describing the stress acting on the tissue. Our approach is based on the linear theory of elasticity and uses an ansatz specifically designed for deformed spherical bodies. We clarify the conditions under which this ansatz can be used, making our results useful also for other contexts in which this ansatz is employed. Our method can be applied to arbitrary radial particle deformations and requires a very low computational effort. The usefulness of the method is demonstrated by an application to experimental data.

[Implementation of a Pilot Project Supporting Parents Suffering from Cancer with Underage Children]. / Implementierung eines Modellprojektes zur phasenübergreifenden Unterstützung von krebskranken Eltern mit minderjährigen Kindern.

OBJECTIVE: Families with one parent suffering from cancer are exposed to extraordinary emotional and organizational burdens, affecting underaged children. To help coordinated access to social and logistic support options and thus reduce the stress on family members, the project Brückenschlag was founded. The aim of this paper was to evaluate the implementation of this pilot project following the healthcare utilization model by Andersen. METHODS: A cross-sectional observational study was conducted using a mixed-method approach. Semi-structured written expert surveys (n=10) and secondary analysis of routine data of the care model (n=171 families) were combined. RESULTS: Quantitative secondary analysis: The participating families had 1-7 children (median (m) 2, range (s) 6). In 66% of the cases, the mother was affected by cancer, in 20% the diseased parent was in a single parent household. The communication structure in these families was rated "limited" to "rather open". Of the total of 171 contacts (study period 9/14 to 11/17), 133 families made use of Brückenschlag; 59.2% of the contacts were made by psycho-oncologists and the social services department of the hospital. If the contact was initiated by the patients themselves or by psycho-oncologists, a guidance was established significantly more frequently (significance of chi-squared test 0.047). Qualitative analysis: There was a lack of awareness and coordination of existing support services and a lack of family resources to use existing support offers. Both the desired and the established support fell primarily in the area of organizational support. Brückenschlag improved networking and took on a navigating function for the families. CONCLUSION: The data collected indicate that in families, matching the German average in their socio-demographic characteristics, a great need for organizational support develops as soon as one parent becomes sick with cancer. The model project Brückenschlag creates an access to support services for families with one parent suffering from cancer.