```xml
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ns4:query_definition xmlns:ns2="http://www.i2b2.org/xsd/cell/crc/psm/1.1/" xmlns:ns4="http://www.i2b2.org/xsd/cell/crc/psm/querydefinition/1.1/" xmlns:ns3="http://www.i2b2.org/xsd/cell/crc/psm/analysisdefinition/1.1/">
    <query_name>GERD [Gastroeso@15:38:30</query_name>
    <query_timing>ANY</query_timing>
    <specificity_scale>0</specificity_scale>
    <panel>
        <panel_number>1</panel_number>
        <panel_timing>ANY</panel_timing>
        <panel_accuracy_scale>100</panel_accuracy_scale>
        <invert>0</invert>
        <total_item_occurrences>1</total_item_occurrences>
        <item>
            <hlevel>5</hlevel>
            <item_name>GERD [Gastroesophageal reflux disease]</item_name>
            <item_key>\\i2b2_DIAG\i2b2\Diagnoses\Digestive system (520-579)\(530) Diseases of esophagus\(530-8) Other specified disorders~\(530-81) Esophageal reflux\</item_key>
            <item_icon>LA</item_icon>
            <tooltip>Diagnoses \ Digestive system \ Diseases of esophagus \ Other specified disorders of esophagus \ Esophageal reflux</tooltip>
            <class>ENC</class>
            <item_is_synonym>true</item_is_synonym>
        </item>
        <item>
            <hlevel>5</hlevel>
            <item_name>Gastroesophageal reflux disease</item_name>
            <item_key>\\i2b2_DIAG\i2b2\Diagnoses\Digestive system (520-579)\(530) Diseases of esophagus\(530-8) Other specified disorders~\(530-81) Esophageal reflux\</item_key>
            <item_icon>LA</item_icon>
            <tooltip>Diagnoses \ Digestive system \ Diseases of esophagus \ Other specified disorders of esophagus \ Esophageal reflux</tooltip>
            <class>ENC</class>
            <item_is_synonym>true</item_is_synonym>
        </item>
    </panel>
</ns4:query_definition>

```

I want to find all instances of Gastroesophageal Reflux Disease (GERD) diagnoses in the i2b2 database, specifically under the category of "Other specified disorders of the esophagus" within the "Diseases of the esophagus" section of the "Digestive system" diagnoses.