June 2016 - This Month in JoVE: Blueberry Analysis, Impact Testing Football Helmets, Stencil Micropatterning of Stem Cells, and a Test for Soil Plasticity

Protocol

Modified Drop Tower Impact Tests for American Football Helmets

G. Alston Rush^1,2, R. Prabhu¹, Gus A. Rush III³, Lakiesha N. Williams¹, M. F. Horstemeyer^2,4

¹Agricultural and Biological Engineering, Mississippi State University, ²Center for Advanced Vehicular Systems, Mississippi State University, ³Rush Sport Medical, ⁴Mechanical Engineering, Mississippi State University

This article provides a novel technique to assess the performance characteristics of American football helmets by inclusion of faceguards during NOCSAE Standard drop tests. Additionally, two more impact locations are proposed to be added to the NOCSAE certification.

Stencil Micropatterning of Human Pluripotent Stem Cells for Probing Spatial Organization of Differentiation Fates

Geetika Sahni*¹, Jun Yuan*¹, Yi-Chin Toh^1,2

¹Department of Biomedical Engineering, National University of Singapore, ²Singapore Institute of Neurotechnology (SINAPSE), National University of Singapore

Human pluripotent stem cells (hPSCs) have the intrinsic ability to differentiate and self-organize into distinct tissue patterns; although this requires the presentation of spatial environmental gradients. We present stencil micropatterning as a simple and robust method to generate biochemical and mechanical gradients for controlling hPSC differentiation patterns.

A Bending Test for Determining the Atterberg Plastic Limit in Soils

José Manuel Moreno-Maroto, Jacinto Alonso-Azcárate

Department of Physical Chemistry, Faculty of Environmental Sciences and Biochemistry, University of Castilla-La Mancha

The traditional standardized test for determining the plastic limit in soils is performed by hand, and the result varies depending on the operator. An alternative method based on bending measurements is presented in this study. This allows the plastic limit to be obtained with a clear and objective criterion.

Construction of Models for Nondestructive Prediction of Ingredient Contents in Blueberries by Near-infrared Spectroscopy Based on HPLC Measurements

Wenming Bai¹, Norio Yoshimura¹, Masao Takayanagi¹, Jingai Che², Naomi Horiuchi², Isao Ogiwara³

¹United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, ²Faculty of Agriculture, Tokyo University of Agriculture and Technology, ³Institute of Agriculture, Tokyo University of Agriculture and Technology

We present here a protocol to construct and validate models for nondestructive prediction of total sugar, total organic acid, and total anthocyanin content in individual blueberries by near-infrared spectroscopy.