Cómo centrar el resumen y las líneas encima y debajo del resumen

Question

Quiero hacer lo siguiente:

1. Necesito una línea encima del resumen y otra línea debajo del resumen. El ancho de las líneas debe ser igual al ancho del resumen. Las líneas no deben ser mayores que el ancho del resumen.
2. En el archivo pdf de salida, aparece la palabra "Resumen" en el centro de la primera línea de la sección del resumen. Necesito que comience como " Abstract. Each chapter should be preceded by an abstract .......", cuyo resumen y el texto del resumen están en la misma primera línea del resumen sin sangría.

MWE:

\documentclass{article}
\usepackage{abstract,lipsum}
\usepackage[paperwidth=7.25in, paperheight=9.5in,bindingoffset=.75in]{geometry}
\begin{document}
\title{Contribution Title}
\author{Name of First Author and Name of Second Author}
\maketitle
\begin{abstract}
\rule{\textwidth}{.5pt}
Each chapter should be preceded by an abstract (10--15 lines long) that summarizes the content. The abstract will appear  and be available with unrestricted access. This allows unregistered users to read the abstract as a teaser for the complete chapter. As a general rule the abstracts will not appear in the printed version of your book unless it is the style of your particular book or that of the series to which your book belongs.
\rule{\textwidth}{.5pt}
\end{abstract}
\section{introduction}
\lipsum*[2]
\end{document}

Answer 1

Puedes redefinir el entorno abstractde esta manera:

\documentclass{article}
\usepackage{abstract,lipsum}
\usepackage[paperwidth=7.25in, paperheight=9.5in,bindingoffset=.75in]{geometry}
\begin{document}
\title{Contribution Title}
\author{Name of First Author and Name of Second Author}
\maketitle

\renewenvironment{abstract}
{\begin{quote}
\noindent \rule{\linewidth}{.5pt}\par{\bfseries \abstractname.}}
{\medskip\noindent \rule{\linewidth}{.5pt}
\end{quote}
}


\begin{abstract}
Each chapter should be preceded by an abstract (10--15 lines long) that summarizes the content. The abstract will appear  and be available with unrestricted access. This allows unregistered users to read the abstract as a teaser for the complete chapter. As a general rule the abstracts will not appear in the printed version of your book unless it is the style of your particular book or that of the series to which your book belongs.
\end{abstract}

\section{introduction}
\lipsum*[2]
\end{document}