You may want to identify certain types of equipment by vendor name and brand or category (., ultracentrifuge vs. prep centrifuge), particularly if they are not commonly found in most labs. It is appropriate to report, parenthetically, the source (vendor) and catalog number for reagents used, ., " ....poly-L-lysine (Sigma #1309) ." When using a method described in another published source, you can save time and words by providing the relevant citation to the source. Always make sure to describe any modifications you have made of a standard or published method.
ln technical writing , the introduction typically includes one or more standard subsections: abstract or summary, preface , acknowledgments, and foreword . Alternatively, the section labeled introduction itself may be a brief section found side-by-side with abstract, foreword, etc. (rather than containing them). In this case the set of sections that come before the body of the book are known as the front matter . When the book is divided into numbered chapters, by convention the introduction and any other front-matter sections are unnumbered and precede chapter 1.