link to ctd database fixed

frontend-js/src/main/js/gui/leftPanel/ChemicalPanel.js

@@ -11,7 +11,7 @@ var PanelControlElementType = require('../PanelControlElementType');
 function ChemicalPanel(params) {
   params.panelName = "chemical";
   params.helpTip = '<p>source: Comparative Toxicogenomics Database <a target="_ctd" href="http://ctdbase.org/">ctdbase.org</a></p>'
-      + '<p>use only the full name of chemicals according to <a target="_ctd_chemicals" href="http://ctdbase.org/voc.go?type=chem/"> ctdbase/chem</a> for search</p>'
+      + '<p>use only the full name of chemicals according to <a target="_ctd_chemicals" href="http://ctdbase.org/voc.go?type=chem"> ctdbase/chem</a> for search</p>'
       + '<p>only curated associations between genes and chemicals with direct evidence to '
       + 'Parkinson Disease (<a href="http://bioportal.bioontology.org/ontologies/1351?p=terms&conceptid=D010300" target="_blank">D010300</a>) are displayed</p>'
       + '<p>separate multiple search by semicolon';