try to debug dynamically determined column name

app.py

@@ -110,11 +110,11 @@ if __name__ == '__main__':
         # determine file type
         if uploaded_file.name.endswith(".csv"):
             df = pd.read_csv(uploaded_file)
-            abstract_col = 'Abstract'
-            title_col = 'Title'
             source_title_col = find_column_name(df, 'Source Title')
-            year_col = 'Year'
-            # preview the uploaded file
+            abstract_col = find_column_name(df, 'Abstract')
+            title_col = find_column_name(df, 'Title')
+            year_col = find_column_name(df, 'Year')
+        # preview the uploaded file
         elif uploaded_file.name.endswith(".txt"):
             df = pd.read_table(uploaded_file, sep='\t')  # Doc: assume contents are seperated by Tabs.
             abstract_col = 'AB'