<HTML> <HEAD> <!-- Apple Help needs these meta tags in the default page --> <meta http-equiv="content-type" content="text/html;charset=iso-8859-1"> <!-- The HTML page title is displayed in Help Viewer's search results window --> <title>LabAnalyst Respirometry Page</title> <!-- The plist CFBundleHelpBookName value --> <meta name="AppleTitle" content="Respirometry Menu"> <script language="JavaScript"> javascript: resizeTo(775, 900) </script> <style> /*---- CROSS BROWSER DROPDOWN MENU ----*/ ul#nav {margin: 6 0 0 10px;} ul.drop a { display:block; color: #000080; font-family: Arial; font-size: 14px; text-decoration: none;} ul.drop, ul.drop li, ul.drop ul { list-style: none; margin: 0; padding: 0; border: 1px solid #fff; background: #e0e0e0; color: #0000FF;} ul.drop { position: relative; z-index: 597; float: left; } ul.drop li { float: left; line-height: 1.3em; vertical-align: middle; zoom: 1; padding: 2px 15px; } ul.drop li.hover, ul.drop li:hover { position: relative; z-index: 599; cursor: default; background: #20b2aa; } ul.drop ul { visibility: hidden; position: absolute; top: 100%; left: 0; z-index: 598; width: 225px; background: #555; border: 1px solid #fff; } ul.drop ul li { float: none; } ul.drop ul ul { top: -2px; left: 100%; } ul.drop li:hover > ul { visibility: visible } </style> </HEAD> <BODY> <A NAME="anchor115459"></A> <TABLE WIDTH="750" HEIGHT="55" BORDER="0" CELLSPACING="2" CELLPADDING="2"> <TR> <TD><IMG SRC="LAXnewlogo.jpg"> &nbsp;&nbsp; &nbsp;&nbsp;</TD> <TD><FONT FACE = "Lucida Grande" COLOR="#000000" SIZE=+2>&nbsp; &nbsp; &nbsp; Respirometry menu</FONT> <BR><FONT FACE = "Lucida Grande" SIZE =+0"> <ul id="nav" class="drop"> <li><a href="LAfilemenu.html">File</a></li> <li><a href="LAeditmenu.html">Edit</a></li> <li>Respirometry</b> <UL> <LI><a href="respirometrybasics.html">Respirometry basics </a> <li><A HREF="#anchor434374">Common functions </A></li> <li><A HREF="#anchor1332598">Compute VO2 </A></li> <li><A HREF="#anchor1295672">Compute VCO2 </A> </li> <li><A HREF="#anchor1919808">sensor humidity compensation </A></li> <li><A HREF="#anchor1338027">Compute EWL </A></li> <li><A HREF="#anchor1338812">VO2 in water </A></li> <li><A HREF="#anchor1338457">'Instantaneous' correction </A></li> <li><A HREF="#anchor237894">O2 heat equivalence </A></li> <li><A HREF="#anchor237894">CO2 heat equivalence </A></li> <li><A HREF="#anchor14336">Effective volume </A></li> <li><A HREF="#anchor433691">Flow measurement accuracy</A></li> </UL> <li><a href="analysismenu.html">Analyze </a> <li><a href="LAviewmenu.html">View </a> <li><a href="LAscriptsmenu.html">Script </a> <li><a href="LAwindowmenu.html">Window </a> <li><a href="LAspecialmenu.html">Special </a> </ul> </ul> </TABLE> <FONT FACE = "Lucida Grande"> <P><IMG SRC="LAXimages/O2StartWindow.jpg" ALIGN="RIGHT">If you are unfamiliar with the fundamentals of respirometry, you might want to read <A HREF="respirometrybasics.html">this page</a> before diving into the rest of this section.<P> These functions convert gas concentrations -- O<sub>2</sub>, CO<sub>2</sub>, H<sub>2</sub>O -- into rates of gas exchange: &nbsp; VO<sub>2</sub>, VCO<sub>2</sub>, evaporative water loss (EWL). &nbsp; Gas concentrations should be in units of % or for EWL, % RH, vapor pressure, or dew point temperature. &nbsp;<FONT COLOR="#FF0000"> <B>The program expects gas concentration to be expressed as difference from reference levels, with reference (baseline) set to zero</b></font> (in the <B><A HREF="LAfilemenu.html#anchor1376813">PREFERENCES</A></B> option in the <B><A HREF="LabAnalystmenu.html">LabHelper</A></B> menu, you can select automatic lag and baseline correction prior to gas exchange calculations).<P> Choose one of two computation modes: <P><B>" Positive-going deflection:</B> &nbsp; Changes in gas concentration are positive with respect to baseline (the default). <P> <B>" Negative-going deflection:</B> &nbsp;Changes in gas concentration are negative with respect to baseline. This can be used if -- as in oxygen consumption -- gas exchange is measured as a depletion of gas concentration. &nbsp; Many users find positive-going deflections more intuitive, but the negative-going option is available if desired. </P> <P>Results are stored either in the source channel or optionally (if there are less than 40 channels) in a new channel. </P> <P>Gas calculations begin with flow rate source selection.&nbsp; Flowrate is entered from the file or by the user, or is obtained from a channel (i.e., recorded from a flow meter).</P> <P><TABLE WIDTH="600" HEIGHT="39" BORDER="1" CELLSPACING="0" CELLPADDING= "3"> <TR> <TD BGCOLOR="#ffffbb" WIDTH="100%" HEIGHT="34"><P ALIGN=CENTER><B><FONT COLOR="#FF0000" SIZE=+2>Important: </FONT></B>&nbsp;&nbsp;<B><FONT SIZE=+1>The program expects flowrates to be in units of ml/min, unless set to liters/min in this window.</FONT></B></TD></TR> </TABLE> <P> For VO<sub>2</sub> and VCO<sub>2</sub> , you need to specify: <P> " whether incurrent CO<sub>2</sub> is absorbed  <B>note that this refers to gas entering the <FONT COLOR="#FF0000">metabolism chamber,</font> NOT to gas entering the analyzers</b>. &nbsp; If you are using  standard air (where the CO<sub>2</sub> concentration is about .04%), this option has little effect.<P> " concentrations of O<sub>2</sub> and CO<sub>2</sub> in ambient gas (FiO<sub>2</sub> and FiCO<sub>2</sub>; default 20.95% and 0.04%, respectively  <B>note that the program expects these to be entered as <FONT COLOR="#FF0000">percentages,</font> not fractions</b>).<P> <P><IMG SRC="LAXimages/HumiditySensorType.jpg" align = "right"> For EWL calculations (VH<sub>2</sub>O), and for VO<FONT SIZE=-1><SUB>2 </SUB></FONT>and VCO<FONT SIZE=-1><SUB>2</SUB></FONT> if you did not use dry incurrent gas, you will also need to indicate the type of sensor used to measure the water vapor content. &nbsp; Most lab-grade humidity sensors output <b>relative humidity</b> (the current humidity relative to saturation water content), <b>dew point</b> (the temperature to which air must be cooled to become saturated with water vapor), or <b>water vapor pressure</b> in units of pressure (usually pascals or kilopascal) or mass/volume (usually micrograms/mL, mg/L or grams/m<sup>3</sup>; all of these are equivalent).<p> For <b>relative humidity</b> sensors, you will also need to indicate operating temperature of the sensor (this is done later; see below).</P> <P><A HREF="#anchor115459"><B>Back to top</B></A></P> <P><B><FONT SIZE=+1>Channel selection:</FONT></B> &nbsp;In the next window (below,left) you select the channel containing gas concentration data, and if you are obtaining flow from a channel, the flow rate channel:</P> <A NAME="anchor1335621"></A></P> <BLOCKQUOTE> <P><IMG SRC="LAXimages/O2channels.gif" ALIGN="BOTTOM"> <IMG SRC="LAXimages/O2configurations.jpg" ALIGN="BOTTOM"></P> </BLOCKQUOTE> <P><B><FONT SIZE=+1>Flow configurations:</FONT></B> &nbsp;Next you select a <B>flow configuration</B> (<B>'Mode' 1, 2, etc.</B>).&nbsp; This specifies the conversion equation to be used, based on where flow rate is measured (upstream or downstream of the animal chamber and gas sensor) and how (and if) the the gas stream is dehumidified and scrubbed of CO<FONT SIZE=-1><SUB>2</SUB></FONT>.</P> <P><IMG SRC="LAXimages/VO2Masks.jpg" ALIGN="RIGHT">The '<B>masks</B>' button (VO<FONT SIZE=-1><SUB>2 </SUB></FONT>and VCO<FONT SIZE=-1><sub>2</SUB> </FONT>only) opens a similar window with a selection of mask configurations (example for VO<sub>2</sub> shown at right).&nbsp; A mask system is defined as one in which unscrubbed ambient gas - usually air - is pulled past the animal to capture exhaled gas (i.e., gas is sucked past the animal under negative pressure).&nbsp; In mask systems all pumps, flow meters, gas analyzers, etc.&nbsp; are downstream.<BR>&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Some mask systems are functionally identical to some 'regular' flow configurations and use the same conversion equations. The '<B>?</B>' button describes these overlaps, and also certain configurations to avoid if possible.</P> <P>Pick the configuration and mode closest to your own respirometry system.&nbsp; It's quite important to give <B>LabAnalyst </B>the right information about your flow arrangement.&nbsp; In some -- <B><i><FONT COLOR="#FF0000" SIZE=+1>but not all </FONT></B></i>-- cases, with 'normal' incurrent concentrations of CO<FONT SIZE=-1><SUB>2 </SUB></FONT>and O<FONT SIZE=-1><SUB>2 </SUB></FONT>(about 0.04% and 20.9%), different modes yield fairly similar results.&nbsp; However, in some cases, serious errors (20% or more) can result if the wrong equations are used (this is most problematic for VO<FONT SIZE=-1><SUB>2</SUB></FONT>).&nbsp; Selecting the appropriate configuration is most critical if the sample gas from the animal chamber has large deflections from ambient concentrations of CO<FONT SIZE=-1><SUB>2 </SUB></FONT>and O<FONT SIZE=-1><SUB>2</SUB></FONT>.&nbsp; An important and easily avoidable error will result if the gas stream at the flow meter contains a significant (but unknown) fraction of water vapor.&nbsp; Therefore it's good practice to<B> use DRY gas whenever possible</B> -- and if you can't, be sure to compensate as described in the next section.</P> </BLOCKQUOTE> <HR ALIGN=LEFT> <table width = "700" Border = "0"> <tr><td>Other links: <td> <FONT FACE = "Lucida Grande"> <ul id="nav" class="drop"> <li><a href="LAHP.html">Overview</a></li> <li><a href="LAIcons.html">Icons</a></li> <li><a href="LAHalerts.html">Alerts</a></li> <li><a href="LAcredits.html">Credits</a></li> <li><a href="http://warthog.ucr.edu/">Warthog Systems</a></li> <li><a href="mailto:chappell@ucr.edu?subject=Warthog%20LabAnalyst%20question">email</a></li> </ul> </table> </BODY> </HTML>