[lemma=□] □
[lemma=in] □
I cut back on the R in that injection , but I generally do n't cut back on the NPH . Most of the biocide and buffer passed the service line branching point and was carried into the storage tank , but a small fraction remained in the injection tee or was diffused into the service line . There are also some small differences in the injection technique . Rather , the unsterile method of use , unpredictable concentrations in street samples , adulterants in the injection mixture , and the lifestyle necessary to procure drugs are responsible for most heroin-associated medical complications .