Tissue Thickness Effects on Immunohistochemical Staining Intensity of Markers of Cancer.

High-quality patient samples are required for reliable immunohistochemistry test outcomes that provide a significant benefit for patient care. Among the preanalytic variables in tissue handling, tissue thickness is thought to be easily controlled; however, whether the thickness of the tissue effects the staining intensity for antibody immunohistochemistry has not been quantitatively demonstrated. To investigate, we cut multiblock tissue sections of tonsil, liver, and kidney at 2, 4, 6, and 8 µm thicknesses. Interferometry measurements of the sectioned paraffin showed a <1 µm variation within a preset microtome thickness. Sections were then immunostained with antibodies targeting different cellular localizations; Ki-67 and BCL6 (nuclear), CD7 (membranous), and cytokeratin (cytoplasmic). A pathologist annotated regions of interest for each marker and performed brightfield and whole-slide visual scoring. Then a pixel-wise processing algorithm determined intensity of each pixel in these regions of interest and binned them into predetermined 0, 1+, 2+, or 3+ intensities. Visual scores from brightfield and whole-slide images were highly correlated to the percentage of pixels in each intensity bin. A stepwise increase was observed in pathologist scores and algorithmically defined percentage of pixels in each bin with increasing thickness demonstrating that changes in preset section thickness impacts staining intensity. The use of tissue thickness outside vendors' recommendations might change the intensity including the proportion of positive and negative cells and eventually the overall diagnosis outcome. Therefore, we recommend that tissue be consistently cut within the middle of thickness range specified by the assay manufacturer.

Two-dimensional condensed phases from particles with tunable interactions.

We present a conceptually simple experimental model for condensed phases, consisting of an ensemble of identical magnetic dipoles on a vibrating bed. The model combines tunable and accurately known pair potentials, equilibration times of seconds, and lattice structure and dynamics visible to the naked eye. Fundamental ensemble properties--specifically phonon propagation, edge relaxation, and binary condensation--are directly observed and quantitatively linked to the underlying pair potential.

Molecular transfer and transport in noncovalent microcontact printing.

Microcontact printing is commonly used to create patterned films of molecules covalently bonded to substrates (e.g., thiols on gold). Here we describe microcontact printing of several types of noncovalently bonding molecules on mica. Due to the weaker interaction of the molecules with the substrate, environmental factors such as temperature and relative humidity play an important role. The vapor pressure of the inks also had a large impact on the fidelity of the stamped patterns. Fingering instabilities were observed for monolayers of octadecanol, docosanol, stearylamine, and stearic acid stamped at moderate relative humidity. The fidelity of the stamped pattern generally increased with the headgroup-surface interaction strength. These stamped monolayer films shed light on molecular transfer and two-dimensional spreading mechanisms.