{"title":"PolyRef™ Calibration Beads","description":"\u003cp\u003e\u003cstrong\u003ePolyRef™ Calibration Beads\u003c\/strong\u003e are monodisperse polymer microspheres with tight size uniformity (CV ≤ 6% for sizes ≥ 100 nm), designed for instrument calibration, particle size reference standards, and biomedical model systems.\u003c\/p\u003e\n\n\u003cp\u003eAvailable in \u003cstrong\u003epolystyrene (PS)\u003c\/strong\u003e and \u003cstrong\u003epolymethyl methacrylate (PMMA)\u003c\/strong\u003e, covering the full 20 nm – 1000 μm range. Each batch is verified by SEM, TEM, optical microscopy, and laser diffraction.\u003c\/p\u003e\n\n\u003cp\u003eCommon applications: SEM\/TEM size calibration, flow cytometry standards, DLS\/NTA reference particles, photonic crystal templates, LCD spacers, light-diffusing layers, and biomedical drug delivery model systems.\u003c\/p\u003e","products":[{"product_id":"monodisperse-polystyrene-ps-microspheres-size-standard-for-sem-flow-cytometry-dls-calibration-polyref™","title":"Monodisperse Polystyrene (PS) Microspheres – Size Standard for SEM, Flow Cytometry \u0026 DLS Calibration | PolyRef™","description":"\u003ch3\u003eProduct Overview\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003ePolyRef™ Monodisperse Polystyrene Microspheres\u003c\/strong\u003e are the workhorse particle size standard for scientific research. Each batch is manufactured under strict process control to achieve narrow size distribution (CV ≤ 6% for sizes ≥ 100 nm) and verified by SEM, TEM, optical microscopy, and laser diffraction. Available in selected sizes from 100 nm to 10 μm; full range from 20 nm to 1000 μm available on request.\u003c\/p\u003e\n\u003cp\u003eParticles are dispersed in ultrapure water at 2.5 wt% (25 mg\/mL) solids content. Sub-5 μm particles are non-crosslinked monodisperse PS; particles ≥ 5 μm are lightly crosslinked for enhanced mechanical and chemical stability.\u003c\/p\u003e\n\u003ch3\u003eWhy PolyRef™ PS Microspheres?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTight monodispersity.\u003c\/strong\u003e CV ≤ 6% across 100 nm – 10 μm range; CV ≤ 10–20% for sub-100 nm sizes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBatch-traceable QC.\u003c\/strong\u003e Every batch includes SEM imaging and size distribution data; COA shipped with each order.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFull size coverage on request.\u003c\/strong\u003e 20 nm to 1000 μm — over 50 size grades available for custom orders.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCited in peer-reviewed journals.\u003c\/strong\u003e RIGOR Science microspheres have been cited in \u003cem\u003eNature Water\u003c\/em\u003e, \u003cem\u003eNature Sustainability\u003c\/em\u003e, \u003cem\u003eAdvanced Science\u003c\/em\u003e, and others.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDirect from the manufacturer.\u003c\/strong\u003e No distributor markup. Custom sizes, surface modifications, and concentrations available.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\" style=\"border-collapse: collapse; width: 100%; height: 411.469px;\"\u003e\n\u003ctbody\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003ePolystyrene (PS) — non-crosslinked (≤ 5 μm) or lightly crosslinked (≥ 5 μm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eCAS No.\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e9003-53-6\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eChemical Formula\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e(C₈H₈)ₙ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eDensity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e1.05–1.07 g\/cm³\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eRefractive Index\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e1.59 (at 589 nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e\u003cstrong\u003eSurface\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003ePlain (hydrophobic); amino \/ carboxyl \/ fluorescent versions available separately\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eSize Uniformity (CV)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e≤ 6% (100 nm – 1000 μm); ≤ 10–20% (20–80 nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e\u003cstrong\u003eAvailable Sizes (Stock)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e100 nm, 200 nm, 500 nm, 1 μm, 2 μm, 3 μm, 5 μm, 10 μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eCustom Sizes\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e20 nm – 1000 μm available on request\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e\u003cstrong\u003eConcentration\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e2.5 wt% (25 mg\/mL); 5 wt% \/ 10 wt% \/ dry powder available on request\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eDispersion\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003eUltrapure water\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003ePackage Size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e10 mL (5 mL, 50 mL, 200 mL on request)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e\u003cstrong\u003eStorage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e2–8 °C for suspensions; room temperature (dry, dark) for powders\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 19.5938px;\"\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e\u003cstrong\u003eShelf Life\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 19.5938px;\"\u003e60 months\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"height: 39.1875px;\"\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003e\u003cstrong\u003eCharacterization\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"height: 39.1875px;\"\u003eSEM, TEM, optical microscopy, laser diffraction; batch-specific COA included\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eApplications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eInstrument calibration — SEM, flow cytometry, DLS, NTA, laser diffraction, optical microscopy\u003c\/li\u003e\n\u003cli\u003eParticle size reference standards and QC\u003c\/li\u003e\n\u003cli\u003ePhotonic crystal self-assembly and templating\u003c\/li\u003e\n\u003cli\u003eLCD spacer applications\u003c\/li\u003e\n\u003cli\u003eLight-scattering and diffusing agents\u003c\/li\u003e\n\u003cli\u003ePorous material templating (sacrificial templating)\u003c\/li\u003e\n\u003cli\u003eHydrodynamic and microfluidic flow tracing\u003c\/li\u003e\n\u003cli\u003eCell-size mimics for membrane and uptake studies (5–10 μm)\u003c\/li\u003e\n\u003cli\u003eDrug delivery carrier model systems\u003c\/li\u003e\n\u003cli\u003eMicroplastic spectral reference (when used alongside PVC \/ LDPE \/ PET \/ PMMA standards)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCustom Specifications\u003c\/h3\u003e\n\u003cp\u003eNeed a size, concentration, or surface chemistry not listed above? RIGOR Science manufactures the full 20 nm – 1000 μm range and offers custom concentrations (5%, 10%, dry powder), packaging sizes (5 mL to 200 mL), and surface functionalization (amino, carboxyl, sulfate, fluorescent). Contact us with your specifications.\u003c\/p\u003e\n\u003cp\u003eSub-micron grades (100–200 nm) are characterized by DLS; micron grades (≥1 μm) are characterized by laser diffraction \/ optical microscopy. Representative data shown; see COA for lot-specific values.\u003c\/p\u003e\n\u003ch3\u003eQuality Documentation\u003c\/h3\u003e\n\u003cp\u003eEach shipment includes a batch-specific Certificate of Analysis (COA) with SEM images and size distribution data.\u003c\/p\u003e","brand":"RIGOR Science","offers":[{"title":"100 nm","offer_id":47646130012323,"sku":null,"price":79.0,"currency_code":"USD","in_stock":true},{"title":"200 nm","offer_id":47646130045091,"sku":null,"price":69.0,"currency_code":"USD","in_stock":true},{"title":"500 nm","offer_id":47646130077859,"sku":null,"price":59.0,"currency_code":"USD","in_stock":true},{"title":"1 μm","offer_id":47646130110627,"sku":null,"price":59.0,"currency_code":"USD","in_stock":true},{"title":"2 μm","offer_id":47646130143395,"sku":null,"price":59.0,"currency_code":"USD","in_stock":true},{"title":"3 μm","offer_id":47646130176163,"sku":null,"price":69.0,"currency_code":"USD","in_stock":true},{"title":"5 μm","offer_id":47646130208931,"sku":null,"price":79.0,"currency_code":"USD","in_stock":true},{"title":"10 μm","offer_id":47646130241699,"sku":null,"price":89.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0755\/0854\/7747\/files\/PS-300nm.png?v=1778504623"},{"product_id":"monodisperse-pmma-microspheres-polymethyl-methacrylate-particles-for-optical-biomedical-flow-tracing-applications-polyref™","title":"Monodisperse PMMA Microspheres – Polymethyl Methacrylate Particles for Optical, Biomedical \u0026 Flow-Tracing Applications | PolyRef™","description":"\u003ch3\u003eProduct Overview\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003ePolyRef™ Monodisperse PMMA Microspheres\u003c\/strong\u003e are highly uniform polymethyl methacrylate (acrylic) particles manufactured under tight process control. Each batch achieves narrow size distribution (CV ≤ 6% for sizes ≥ 100 nm) and is verified by SEM, TEM, optical microscopy, and laser diffraction. Available in selected sizes from 100 nm to 10 μm; full range from 30 nm to 1000 μm available on request.\u003c\/p\u003e\n\u003cp\u003ePMMA combines optical transparency, a refractive index (~1.46) close to water and many aqueous media, and excellent biocompatibility — making it the preferred microsphere material for refractive-index-matched optical work, PIV \/ micro-PIV flow tracing, and biomedical model systems.\u003c\/p\u003e\n\u003ch3\u003eWhy PMMA Over PS?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLower refractive index (1.46 vs 1.59 for PS).\u003c\/strong\u003e Closer match to water and aqueous buffers — ideal for refractive-index-matched suspensions, transparent composite systems, and reduced light scattering in optical setups.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBiocompatible material chemistry.\u003c\/strong\u003e PMMA is the same polymer family used in intraocular lenses (IOLs), bone cement, dental resins, and dentures — making it the preferred polymer microsphere for cell culture model systems, drug delivery, and biomedical research.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical clarity.\u003c\/strong\u003e Excellent transmittance across UV-visible range; widely used in light-diffusing layers, anti-glare coatings, and matte-finish cosmetic fillers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHigher density than PS (1.18–1.20 g\/cm³).\u003c\/strong\u003e Settles in water faster than PS — useful for sedimentation-based separation and density-matching studies in glycerol or sucrose solutions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSolvent resistance.\u003c\/strong\u003e Insoluble in water, methanol, and most aqueous solvents; suitable for a wide range of buffers and biological media.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable border=\"1\" cellpadding=\"8\" cellspacing=\"0\" style=\"border-collapse: collapse; width: 100%;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePolymethyl Methacrylate (PMMA) — non-crosslinked (≤ 5 μm) or crosslinked (≥ 5 μm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCAS No.\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e9011-14-7\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eChemical Formula\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e(C₅H₈O₂)ₙ\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDensity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1.18–1.20 g\/cm³\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRefractive Index\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1.46 (at 589 nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eHydrophobicity\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eModerate (less hydrophobic than PS)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSurface\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePlain ester surface; amino \/ carboxyl \/ fluorescent \/ colored versions available separately\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSize Uniformity (CV)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e≤ 6% (100 nm – 1000 μm); ≤ 10% (30–80 nm)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAvailable Sizes (Stock)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e100 nm, 200 nm, 500 nm, 1 μm, 2 μm, 3 μm, 5 μm, 10 μm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCustom Sizes\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e30 nm – 1000 μm available on request\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eConcentration\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e2.5 wt% (25 mg\/mL); 5 wt% \/ 10 wt% \/ dry powder available on request\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDispersion\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eUltrapure water (some sub-100 nm grades may contain trace surfactant)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePackage Size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e10 mL (5 mL, 50 mL, 200 mL on request)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eStorage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e2–8 °C (sealed) for suspensions; room temperature for dry powders\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eShelf Life\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e60 months\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCharacterization\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSEM, TEM, optical microscopy, laser diffraction; batch-specific COA included\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eApplications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eRefractive-index-matched optical experiments (RI ≈ 1.46 ≈ water\/buffer)\u003c\/li\u003e\n\u003cli\u003eParticle Image Velocimetry (PIV) and micro-PIV flow tracer\u003c\/li\u003e\n\u003cli\u003eBiomedical model systems — drug delivery carriers, cell-size mimics, scaffold porogens\u003c\/li\u003e\n\u003cli\u003eCosmetic formulations — matte finish, soft-focus fillers, exfoliating agents\u003c\/li\u003e\n\u003cli\u003eLight-diffusing layers and anti-glare optical films\u003c\/li\u003e\n\u003cli\u003eLCD spacer applications\u003c\/li\u003e\n\u003cli\u003eInstrument calibration — flow cytometry, DLS, NTA, optical microscopy\u003c\/li\u003e\n\u003cli\u003ePhotonic crystal self-assembly templates\u003c\/li\u003e\n\u003cli\u003ePorous material templating (sacrificial templating)\u003c\/li\u003e\n\u003cli\u003eMicroplastic spectral reference (PMMA is a regulated polymer in microplastic monitoring)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCustom Specifications\u003c\/h3\u003e\n\u003cp\u003eNeed a size, concentration, or surface chemistry not listed above? RIGOR Science manufactures the full 30 nm – 1000 μm range and offers custom concentrations (5%, 10%, dry powder), packaging sizes (5 mL to 200 mL), and surface functionalization (amino, carboxyl, fluorescent, colored). Contact us with your specifications.\u003c\/p\u003e\n\u003ch3\u003eQuality Documentation\u003c\/h3\u003e\n\u003cp\u003eEach shipment includes a batch-specific Certificate of Analysis (COA) with SEM images and size distribution data.\u003c\/p\u003e\n\u003cp\u003eSub-micron grades (100–200 nm) are characterized by DLS; micron grades (≥1 μm) are characterized by laser diffraction \/ optical microscopy. Representative data shown; see COA for lot-specific values.\u003c\/p\u003e","brand":"RIGOR Science","offers":[{"title":"100 nm","offer_id":47648304464035,"sku":null,"price":89.0,"currency_code":"USD","in_stock":true},{"title":"200 nm","offer_id":47648304496803,"sku":null,"price":79.0,"currency_code":"USD","in_stock":true},{"title":"500 nm","offer_id":47648304529571,"sku":null,"price":69.0,"currency_code":"USD","in_stock":true},{"title":"1 μm","offer_id":47648304562339,"sku":null,"price":69.0,"currency_code":"USD","in_stock":true},{"title":"2 μm","offer_id":47648304595107,"sku":null,"price":69.0,"currency_code":"USD","in_stock":true},{"title":"3 μm","offer_id":47648304627875,"sku":null,"price":79.0,"currency_code":"USD","in_stock":true},{"title":"5 μm","offer_id":47648304660643,"sku":null,"price":89.0,"currency_code":"USD","in_stock":true},{"title":"10 μm","offer_id":47648304693411,"sku":null,"price":99.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0755\/0854\/7747\/files\/200nmpmma.jpg?v=1778553098"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0755\/0854\/7747\/collections\/300nm-3_ps.jpg?v=1778668490","url":"https:\/\/rigorsci.com\/collections\/calibration-beads.oembed","provider":"RIGOR science","version":"1.0","type":"link"}