31:T5d7,viewof dilutionInput = { const row = html`

Lysate volume µL × 10^

`; const volumeInput = row.querySelector(".volume"); const exponentInput = row.querySelector(".exponent"); // Default values volumeInput.value = "100"; exponentInput.value = "-5"; function setValue() { row.value = { lysateVolumeUl: Number(volumeInput.value), dilutionExponent: Number(exponentInput.value) }; } function update() { setValue(); row.dispatchEvent( new Event("input", { bubbles: true }) ); } // Set initial value setValue(); volumeInput.addEventListener("input", update); exponentInput.addEventListener("input", update); return row; }32:Ta11,html`

SeaPhages Full Plate Titer Calculator

Calculate how much lysate you need to make a webbed plate. No ruler? Use the image below to estimate plaque diameter.

Plaques needed for a webbed plate

${formatNumber(calculation.plaquesForWebbedPlate, 0)} plaques

Plate area = π × ${plateRadiusMm}²
Plaque area = π × (${plaqueDiameterMm} ÷ 2)²
Plaques needed = plate area ÷ plaque area

Lysate titer

${ Number.isFinite(calculation.lysateTiterPfuPerMl) ? html`

${formatScientific(calculation.lysateTiterPfuPerMl, 1)} pfu/mL

Titer = plaques ÷ dilution used × 1000
Titer = ${numberOfPlaques} ÷ ${dilutionUsed} × 1000

` : html`

Please enter a valid positive dilution, such as 100e-5 or 5e-4.

` }

Lysate needed for a webbed plate

${ Number.isFinite(calculation.stockLysateVolumeUl) ? html`

${calculation.practicalDilution}

Stock lysate volume = plaques needed ÷ titer × 1000
Stock lysate volume = ${formatScientific(calculation.stockLysateVolumeUl, 2)} µL

` : html`

Lysate volume cannot be calculated until the titer is valid.

` }

`33:[{"id":"1e826e47e6dd3483d557f93111c26082a0d607bd3d7f4eea4e9b6c0543eb08b770b353c9f3394bc5044fad2409f33dbd38337291223990950dc37028aec5122f","href":"https://static.observableusercontent.com/files/1e826e47e6dd3483d557f93111c26082a0d607bd3d7f4eea4e9b6c0543eb08b770b353c9f3394bc5044fad2409f33dbd38337291223990950dc37028aec5122f","name":"plaqueimage","type":"image/png","lastModified":1788450006358,"size":183581}] 2f:{"title":"Phage Titer Calculator","cells":[{"id":1,"value":"# Phage Titer Calculator\nCalculate the amount of lysate to make a webbed plate.","pinned":false,"hidden":false,"mode":"md"},{"id":24,"value":"html`\n\n\n

Estimate plaque diameter

\n\n

\n Measure or estimate the plaque diameter in millimeters.\n

\n\n \n

\n`","pinned":false,"hidden":false,"mode":"ojs"},{"id":2,"value":"viewof plaqueDiameterMm = Inputs.range([0.1, 20], {\n label: \"Estimated plaque diameter, mm\",\n value: 1.5,\n step: 0.1\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":3,"value":"viewof numberOfPlaques = Inputs.range([1, 300], {\n label: \"Plaques counted\",\n value: 20,\n step: 1\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":5,"value":"$31","pinned":false,"hidden":false,"mode":"ojs"},{"id":23,"value":"$32","pinned":false,"hidden":false,"mode":"ojs"},{"id":7,"value":"---\n# Code","pinned":false,"hidden":false,"mode":"md"},{"id":9,"value":"plateRadiusMm = 45","pinned":false,"hidden":false,"mode":"ojs"},{"id":10,"value":"lysateVolumeUl = dilutionInput.lysateVolumeUl","pinned":false,"hidden":false,"mode":"ojs"},{"id":11,"value":"dilutionExponent = dilutionInput.dilutionExponent","pinned":false,"hidden":false,"mode":"ojs"},{"id":12,"value":"dilutionUsed =\n dilutionInput.lysateVolumeUl *\n Math.pow(10, dilutionInput.dilutionExponent)","pinned":false,"hidden":false,"mode":"ojs"},{"id":13,"value":"parsePositiveNumber = (value) => {\n const parsed = Number(String(value).trim());\n return Number.isFinite(parsed) && parsed > 0 ? parsed : NaN;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":14,"value":"formatNumber = (value, maxDigits = 2) => {\n if (!Number.isFinite(value)) return \"—\";\n\n return new Intl.NumberFormat(\"en-US\", {\n maximumFractionDigits: maxDigits\n }).format(value);\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":15,"value":"formatScientific = (value, digits = 1) => {\n if (!Number.isFinite(value)) return \"—\";\n return value.toExponential(digits);\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":16,"value":"formatPracticalDilution = (stockVolumeUl) => {\n if (!Number.isFinite(stockVolumeUl) || stockVolumeUl <= 0) return \"—\";\n\n // Converts tiny stock volumes into a practical dilution volume.\n // Example: 0.101 µL stock → 10.1 µL of 10^-2 dilution\n const stockExp = Math.floor(Math.log10(stockVolumeUl));\n const dilutionExp = stockExp - 1;\n const dilutedVolumeUl = stockVolumeUl / Math.pow(10, dilutionExp);\n\n return `${formatNumber(dilutedVolumeUl, 1)} µL of 10^(${dilutionExp}) dilution`;\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":17,"value":"calculation = {\n const plaqueRadiusMm = plaqueDiameterMm / 2;\n\n const plateAreaMm2 = Math.PI * Math.pow(plateRadiusMm, 2);\n const plaqueAreaMm2 = Math.PI * Math.pow(plaqueRadiusMm, 2);\n\n const plaquesForWebbedPlate = Math.floor(plateAreaMm2 / plaqueAreaMm2);\n\n const dilutionStockEquivalentUl = parsePositiveNumber(dilutionUsed);\n\n const lysateTiterPfuPerMl = Number.isFinite(dilutionStockEquivalentUl)\n ? (numberOfPlaques / dilutionStockEquivalentUl) * 1000\n : NaN;\n\n const stockLysateVolumeUl = Number.isFinite(lysateTiterPfuPerMl)\n ? (plaquesForWebbedPlate / lysateTiterPfuPerMl) * 1000\n : NaN;\n\n return {\n plateAreaMm2,\n plaqueAreaMm2,\n plaquesForWebbedPlate,\n dilutionStockEquivalentUl,\n lysateTiterPfuPerMl,\n stockLysateVolumeUl,\n practicalDilution: formatPracticalDilution(stockLysateVolumeUl)\n };\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":18,"value":"dilutionUsedDisplay = `${lysateVolumeUl} µL of 10^(${dilutionExponent}) dilution`","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W33","stdlib":"2","titling":"auto"}