Perhaps it has something to do with
objX.WriteElementString("pubDate", dr["NewsDate"].ToString());
The DateTime object from the database is cast to the computer/current thread culture info.
Where under
objX.WriteElementString("lastBuildDate", String.Format("{0:R}", DateTime.Now));
You tell how the format of the DateTime is printed.
Try
http://cyber.law.harvard.edu/rss/rss.html[
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