In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

[Q]: In a Drosophila follicle the oocyte always occupies a posterior position among a group of sixteen germline cells. Although the importance of this cell arrangement for the subsequent formation of the anterior-posterior axis of the embryo is well documented, the molecular mechanism responsible for the posterior localization of the oocyte was unknown. Here we show that the homophilic adhesion molecule DE-cadherin mediates oocyte positioning. During follicle biogenesis, DE-cadherin is expressed in germline (including oocyte) and surrounding follicle cells, with the highest concentration of DE-cadherin being found at the interface between oocyte and posterior follicle cells. Mosaic analysis shows that DE-cadherin is required in both germline and follicle cells for correct oocyte localization, indicating that germline-soma interactions may be involved in this process. By analysing the behaviour of the oocyte in follicles with a chimaeric follicular epithelium, we find that the position of the oocyte is determined by the position of DE-cadherin-expressing follicle cells, to which the oocyte attaches itself selectively. Among the DE-cadherin positive follicle cells, the oocyte preferentially contacts those cells that express higher levels of DE-cadherin. On the basis of these data, we propose that in wild-type follicles the oocyte competes successfully with its sister germline cells for contact to the posterior follicle cells, a sorting process driven by different concentrations of DE-cadherin. This is, to our knowledge, the first in vivo example of a cell-sorting process that depends on differential adhesion mediated by a cadherin.
[A]: Drosophila oocyte localization is mediated by differential cadherin-based adhesion.

[Q]: Age-related degeneration of basal forebrain cholinergic neurons (BFCNs) occurs early and contributes significantly to cognitive decline in Alzheimer's disease (AD). Proper function and morphology of BFCNs depends on the supply of nerve growth factor (NGF) from the cortex and the hippocampus. A large number of experiments have shown that decreased supply of NGF at the level of BFCN cell bodies leads to loss of neuronal markers and shrinkage, mimicking what is observed in AD. The delivery of sufficient amounts of NGF signal to BFCN cell bodies depends on the effective participation of several factors including sufficient synthesis and release of NGF, adequate synthesis and expression of NGF receptors by BFCNs, normal signaling and retrograde transport of NGF-receptor complex, and finally effective induction of gene expression by NGF. In the past few years it has become clear that decreased amounts of NGF at the level of BFCN cell bodies is largely due to failed retrograde transport rather than decreased synthesis, binding or expression of NGF receptors in the BFCN terminals. We will discuss in vivo evidence supporting decreased retrograde transport of NGF in a mouse model with BFCN degeneration, and will attempt to match these findings with our studies in postmortem human AD brain. We will speculate about the possible mechanisms of failed NGF retrograde transport and its relationship to AD pathology.
[A]: Alzheimer's disease and NGF signaling

[Q]: Size-exclusion chromatography coupled with SAXS (small-angle X-ray scattering), often performed using a flow-through capillary, should allow direct collection of monodisperse sample data. However, capillary fouling issues and non-baseline-resolved peaks can hamper its efficacy. The UltraScan solution modeler (US-SOMO) HPLC-SAXS (high-performance liquid chromatography coupled with SAXS) module provides a comprehensive framework to analyze such data, starting with a simple linear baseline correction and symmetrical Gaussian decomposition tools [Brookes, Perez, Cardinali, Profumo, Vachette & Rocco (2013 ). J. Appl. Cryst.46, 1823-1833]. In addition to several new features, substantial improvements to both routines have now been implemented, comprising the evaluation of outcomes by advanced statistical tools. The novel integral baseline-correction procedure is based on the more sound assumption that the effect of capillary fouling on scattering increases monotonically with the intensity scattered by the material within the X-ray beam. Overlapping peaks, often skewed because of sample interaction with the column matrix, can now be accurately decomposed using non-symmetrical modified Gaussian functions. As an example, the case of a polydisperse solution of aldolase is analyzed: from heavily convoluted peaks, individual SAXS profiles of tetramers, octamers and dodecamers are extracted and reliably modeled.
[A]:
US-SOMO HPLC-SAXS module: dealing with capillary fouling and extraction of pure component patterns from poorly resolved SEC-SAXS data