A hybrid approach to multi-scale modelling of cancer

In this paper, we review multi-scale models of solid tumour growth and discuss a middle-out framework that tracks individual cells. By focusing on the cellular dynamics of a healthy colorectal crypt and its invasion by mutant, cancerous cells, we compare a cell-centre, a cell-vertex and a continuum model of cell proliferation and movement. All models reproduce the basic features of a healthy crypt: cells proliferate near the crypt base, they migrate upwards and are sloughed off near the top. The models are used to establish conditions under which mutant cells are able to colonize the crypt either by top-down or by bottom-up invasion. While the continuum model is quicker and easier to implement, it can be difficult to relate system parameters to measurable biophysical quantities. Conversely, the greater detail inherent in the multi-scale models means that experimentally derived parameters can be incorporated and, therefore, these models offer greater scope for understanding normal and diseased crypts, for testing and identifying new therapeutic targets and for predicting their impacts.     

Oxalic Acid Enabled Emission Enhancement and Continuous Extraction of Chloride from Cesium Lead Chloride/Bromide Perovskite Nanocrystals

All‐inorganic cesium lead halide perovskite nanocrystals (NCs) have demonstrated excellent optical properties and an encouraging potential for optoelectronic applications; however, mixed‐halide perovskites, especially CsPb(Cl/Br)₃ NCs, still show lower photoluminescence quantum yields (PL QY) than the corresponding single‐halide materials. Herein, anhydrous oxalic acid is used to post‐treat CsPb(Cl/Br)₃ NCs in order to initially remove surface defects and halide vacancies, and thus, to improve their PL QY from 11% to 89% for the emission of 451 nm. Furthermore, due to the continuous chelating reaction with the oxalate ion, chloride anions from the mixed‐halide CsPb(Cl/Br)₃ perovskite NCs could be extracted, and green emitting CsPbBr₃ NCs with PL QY of 85% at 511 nm emission are obtained. Besides being useful to improve the emission of CsPb(Cl/Br)₃ NCs, the oxalic acid treatment strategy introduced here provides a further tool to adjust the distribution of halide anions in mixed‐halide perovskites without using any halide additives.     

Temperature Correction and Strut Loads in Central Artery Excavations

Braced excavations for the Central Artery/Tunnel project in Boston, Mass. include several instrumented sections for monitoring excavation and ground response to soil removal and strut installation. Strain in the struts is measured using thermally matched vibrating wire strain gauges (VWSGs). This paper presents issues related to strut load interpretation using VWSG data and the difficulties and errors associated with the use of field data. The paper presents a procedure to separate earth load from thermal load induced in the struts due to temperature variation throughout construction. The procedure is an extension of a method that uses measured temperature and corresponding load change to compute a thermal (temperature change induced) load coefficient. The procedure emphasizes the dependency of the thermal load coefficient on construction stage and support configuration. A numerical analysis is presented to support the proposed procedure. Strut loads and earth pressure diagrams are presented using the proposed procedure. Comparisons are made between measured loads and the design load envelope developed prior to construction.     

Advancing parallel solution phase library synthesis through efficient purification, quantitation, and characterization techniques

Historically, access to large numbers of quality compounds in a parallel solution phase library synthesis environment has been hindered by the inability to rapidly purify, quantitate, and characterize solution phase libraries in an efficient and cost effective manner. At Neurogen Corporation, we overcome these barriers by employing a collection of novel workstations in the High Speed Synthesis (HSS) group that are tightly integrated into our informatics architecture. This approach supports rapid and reliable instrument operation, rapid interpretation of results, and decision analysis for further downstream tasks and processing. Our movement of library samples and data from workstation to workstation facilitates synthesis throughput and the utilization of equipment, creating a cost-effective library production environment.     

Prevalence, Course, and Predictors of Emotional Distress in Pregnant and Parenting Adolescents.

This study examines trajectories and correlates of emotional distress symptoms in pregnant adolescents (n = 203) and nulliparous adolescents (n = 188) from economically disadvantaged communities over an 18-month period. For both groups, the prevalence of significant emotional distress exceeded expectation based on adolescent norms; however, the severity of symptoms did not differ between the 2 groups. Results from growth curve modeling revealed a significant decline in symptoms during the study period for both groups, but pregnant adolescents experienced a different pattern of decline. Also, certain interpersonal factors (e.g., history of physical maltreatment, partner support) appeared to play a more important role in the emotional well-being of pregnant and parenting adolescents relative to nulliparous adolescents. Implications for early identification and intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Misperceived risk among female adolescents: Social and psychological factors associated with sexual risk accuracy.

This study of 411 urban female adolescents had 3 objectives: (a) assess the relationship between perceived risk and sexual risk behavior (condom use, number of partners, partner risk, presence of STDs, and aggregate sexual risk), (b) assess the accuracy of risk perceptions, and (c) identify variables related to inaccurate sexual risk perceptions. Participants were classified as accurate or inaccurate risk perceivers on the basis of actual sexual behavior and perceived risk. Accurate versus inaccurate risk perceivers were compared on psychological maintenance variables (self-esteem, distress, and coping), relationship context variables (partnership duration and pressure to have unprotected sex), and risk knowledge at different levels of sexual risk. Approximately half of the participants underestimated the risk of their sexual behavior. Accurate and inaccurate risk perceivers differed on risk knowledge, partnership duration, and pressure to have unprotected sex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)