Identifying Marijuana Use Behaviors Among Youth Experiencing Homelessness Using a Machine Learning-Based Framework: Development and Evaluation Study.

Background: Youth experiencing homelessness face substance use problems disproportionately compared to other youth. A study found that 69% of youth experiencing homelessness meet the criteria for dependence on at least 1 substance, compared to 1.8% for all US adolescents.

Rapid changes of light microscopic indices of osteoclast-bone relationships correlated with electron microscopy.

The relationships of tibial endosteal osteoclasts to bone surfaces were quantitatively evaluated during initiation of calcium repletion in calcium-deficient rats. To do this, indices of osteoclast-bone relationships obtained by light microscopy were devised and evaluated by comparing with those obtained by electron microscopy (EM). These indices are the percent of the osteoclast width that (1) exhibits markers indicative of a ruffled border, (2) is in close contact with bone, (3) is isolated from bone by other cell types, and (4) is separated from bone by intercellular material.