attr("dx", nodeSizeA / 2)
    .attr("dy", nodeSizeA / 2 + 1);

cellA.append("text")
    .attr("class", "label")
    .attr("dx", nodeSizeA / 2)
    .attr("dy", nodeSizeA + 24 + 8)
    .text(function(d) { return d; });

cellA.append("rect")
    .style("opacity", 0)
    .attr("transform", "translate(-" + ((xa.step() - nodeSizeA) / 2) + ",-" + (nodeMargin + (networkMargin - networkHeightB) / 2) + ")")
    .attr("width", xa.step())
    .attr("height", networkHeightA + (networkMargin - networkHeightA) / 2);

//
/