This specification covers the general and design requirements for two types of cell-type ovens based on their rates of ventilation, for determining loss in weight or changes in properties of materials on heating at elevated temperatures. This specification takes into account the fact that chamber geometry, rate of ventilation, and temperature each affect the rate of loss of volatile constituents from a material, or the rate of change in other properties. Hence, this oven is recommended whenever the results are dependent on the time and temperature of heating, the amount of ventilation, or both.1.1 This specification covers the general requirements of a cell-type oven with controlled rates of ventilation for determining loss in weight or changes in properties of materials on heating at elevated temperatures. These specifications take into account the fact that chamber geometry, rate of ventilation, and temperature each affect the rate of loss of volatile constituents from a material, or the rate of change in other properties. This oven is recommended whenever the results are dependent on the time and temperature of heating, the amount of ventilation, or both. It is assumed that specific requirements such as specimen shape and dimensions, rate of ventilation, time, and temperature will be included in the applicable material specifications or test methods.NOTE 1: Ovens meeting these specifications have been found useful for determination of plasticizer loss in plastics, and for controlled aging of elastomers and plastics.1.2 The values stated in inch-pound units are to be regarded as the standard.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 Rigid gas-filled closed-cell foam insulations include all cellular plastic insulations which rely on a blowing agent (or gas), other than air, for thermal resistance values. At the time of manufacture, the cells of the foam usually contain their highest percentage of blowing agent and the lowest percentage of atmospheric gases. As time passes, the relative concentrations of these gases change due primarily to diffusion. This results in a general reduction of the thermal resistance of the foam due to an increase in the thermal conductivity of the resultant cell gas mixture. These phenomena are typically referred to as foam aging.5.1.1 For some rigid gas-filled closed-cell foam insulation products produced using blowing agent gases that diffuse very rapidly out of the full-thickness foam product, such as expanded polystyrene, there is no need to accelerate the aging process.5.1.2 Physical gas diffusion phenomena occur in three dimensions. The one-dimensional form of the diffusion equations used in the development of this practice are valid only for planar geometries, that is, for specimens that have parallel faces and where the thickness is much smaller than the width and much smaller than the length.NOTE 3: Please see Appendix X3 for a discussion of the theory of accelerated aging via thin slicing.NOTE 4: Theoretical and experimental evaluations of the aging of insulation in radial forms, such as pipe insulation, have been made. (6) However, these practices have not evolved to the point of inclusion in the test standard.5.2 The change in thermal resistance due to the phenomena described in 5.1 usually occurs over an extended period of time. Information regarding changes in the thermal resistance of these materials as a function of time is required in a shorter period of time so that decisions regarding formulations, production, and comparisons with other materials can be made.5.3 Specifications C578, C591, C1029, C1126 and C1289 on rigid closed-cell foams measure thermal resistance after conditioning at 23 ± 1°C [73 ± 2°F] for 180 ± 5 days from the time of manufacture or at 60 ± 1°C [140 ± 2°F] for 90 days. This conditioning can be used for comparative purposes, but is not sufficient to describe long-term thermal resistance. This requirement demonstrates the importance of the aging phenomena within this class of products.5.4 The Prescriptive Method in Part A provides long-term thermal resistance values on a consistent basis for a variety of purposes, including product evaluation, specifications, or product comparisons. The consistent basis for these purposes is provided by a series of specific procedural constraints, which are not required in the Research Method described in Part B. The values produced by the Prescriptive Method correspond to the thermal resistance at an age of five years, which corresponds closely to the average thermal resistance over a 15-year service life (7, 8).5.4.1 It is recommended that any material standard that refers to C1303 to provide a product rating for long-term thermal resistance specify the Part A Test Method of C1303.5.5 The Research Method in Part B provides a relationship between thermal conductivity, age, and product thickness. The calculation methods given in Part B can be used to predict the resistance at any specific point in time as well as the average resistance over a specific time period.NOTE 5: The 5-year aged values produced in Part A can be derived from the Part B data only if all other Part A requirements are met.5.6 This test method addresses three separate elements relating to the aging of rigid closed-cell plastic foams.5.6.1 Specimen Preparation—Techniques for the preparation of thin flat specimens, including their extraction from the “as manufactured” product, and the measurement of specimen thickness are discussed.5.6.2 Measurement of the Thermal Resistance—Thermal resistance measurements, taken at scheduled times, are an integral part of the test method.5.6.3 Interpretation of Data—Procedures are included to properly apply the theory and techniques to achieve the desired goals.1.1 This test method covers a procedure for predicting the long-term thermal resistance (LTTR) of unfaced or permeably faced rigid gas-filled closed-cell foam insulations by reducing the specimen thickness to accelerate aging under controlled laboratory conditions (1-5) .2NOTE 1: See Terminology, 3.2.1, for the meaning of the word aging within this standard.1.2 Rigid gas-filled closed-cell foam insulation includes all cellular plastic insulations manufactured with the intent to retain a blowing agent other than air.1.3 This test method is limited to unfaced or permeably faced, homogeneous materials. This method is applied to a wide range of rigid closed-cell foam insulation types, including but not limited to: extruded polystyrene, polyurethane, polyisocyanurate, and phenolic. This test method does not apply to impermeably faced rigid closed-cell foams or to rigid closed-cell bun stock foams.NOTE 2: See Note 8 for more details regarding the applicability of this test method to rigid closed-cell bun stock foams.1.4 This test method utilizes referenced standard test procedures for measuring thermal resistance. Periodic measurements are performed on specimens to observe the effects of aging. Specimens of reduced thickness (that is, thin slices) are used to shorten the time required for these observations. The results of these measurements are used to predict the long-term thermal resistance of the material.1.5 The test method is given in two parts. The Prescriptive Method in Part A provides long-term thermal resistance values on a consistent basis that can be used for a variety of purposes, including product evaluation, specifications, or product comparisons. The Research Method in part B provides a general relationship between thermal conductivity, age, and product thickness.1.5.1 To use the Prescriptive Method, the date of manufacture must be known, which usually involves the cooperation of the manufacturer.1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 Table of Contents:   Section 1Reference Documents 2Terminology 3Summary of Test Method 4 5Part A: The Prescriptive Method 6  Applicability 6.1    Qualification Requirements 6.1.1    Facing Permeability 6.1.2  Apparatus 6.2  Sampling 6.3    Schedule 6.3.1  Specimen Preparation 6.4    Goal 6.4.1    Schedule 6.4.2    Replicate Test Specimen Sets 6.4.3    Specimen Extraction 6.4.4    Slice Flatness 6.4.5    Slice Thickness 6.4.6    Stack Composition 6.4.7  Storage Conditioning 6.5  Test Procedure 6.6    Thermal Resistance Measurement Schedule 6.6.1    Thermal Resistance Measurements 6.6.2    Product Density 6.6.3  Calculations 6.7Part B: The Research Method 7  Background 7.1  TDSL Apparatus 7.2  Sampling Schedule 7.3  Specimen Preparation 7.4  Storage Conditioning 7.5  Test Procedure 7.6  Calculations 7.7Reporting 8 Reporting for Part A, the Prescriptive Method 8.1 Reporting for Part B, the Research Method 8.2Precision and Bias 9Keywords 10Mandatory Information – Qualification Annex A1 Specimen Preparation A1.1 Homogeneity Qualification A1.2Thermal Conductivity Equivalence Test Procedure A1.3 Alternate Product Thickness Qualification A1.4Example Calculations A1.5Mandatory Information-Preparation of Test Specimens for Spray-Foam Products Annex A2Effect Of TDSL Appendix X1History of the Standard Appendix X2Theory of Foam Aging Appendix X3References  1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 The calculated error in the photovoltaic device current determined from the spectral mismatch parameter can be used to determine if a measurement will be within specified limits before the actual measurement is performed.5.2 The spectral mismatch parameter also provides a means of correcting the error in the measured device current due to spectral mismatch.5.2.1 The spectral mismatch parameter is formulated as the fractional error in the short-circuit current due to spectral and temperature differences.5.2.2 Error due to spectral mismatch is corrected by multiplying a reference cell’s measured short-circuit current by M , a technique used in Test Methods E948 and E1036.5.3 Because all spectral quantities appear in both the numerator and the denominator in the calculation of the spectral mismatch parameter (see 8.1), multiplicative calibration errors cancel, and therefore only relative quantities are needed (although absolute spectral quantities may be used if available).5.4 Temperature-dependent spectral mismatch is a more accurate method to correct photovoltaic current measurements compared with fixed-value temperature coefficients.31.1 This test method provides a procedure for the determination of a spectral mismatch parameter used in performance testing of photovoltaic devices.1.2 The spectral mismatch parameter is a measure of the error introduced in the testing of a photovoltaic device that is caused by the photovoltaic device under test and the photovoltaic reference cell having non-identical quantum efficiencies, as well as mismatch between the test light source and the reference spectral irradiance distribution to which the photovoltaic reference cell was calibrated.1.2.1 Examples of reference spectral irradiance distributions are Tables E490 or G173.1.3 The spectral mismatch parameter can be used to correct photovoltaic performance data for spectral mismatch error.1.4 Temperature-dependent quantum efficiencies are used to quantify the effects of temperature differences between test conditions and reporting conditions.1.5 This test method is intended for use with linear photovoltaic devices in which short-circuit is directly proportional to incident irradiance.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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1.1 This test method covers a procedure for the determination of a spectral mismatch parameter used in the testing of photovoltaic devices. 1.2 The spectral mismatch parameter is a measure of the error, introduced in the testing of a photovoltaic device, caused by mismatch between the spectral responses of the photovoltaic device and the photovoltaic reference cell, as well as mismatch between the test light source and the reference spectral irradiance distribution to which the photovoltaic reference cell was calibrated. Examples of reference spectral irradiance distributions are Tables E 490, E 891, or E 892. 1.3 The spectral mismatch parameter can be used to correct photovoltaic performance data for spectral mismatch error. 1.4 This test method is intended for use with linear photovoltaic devices. 1.5 There is no similar or equivalent ISO standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.7 The values stated in SI units are to be regarded as the standard.

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4.1 This practice describes a cell adhesion method that can be used to provide a detachment percent at a given RCF for cells that have adhered to a substrate, typically for a short time. The information generated by this practice can be used to obtain a semi-quantitative measurement of the adhesion of cells to either an uncoated or pre-coated substrate, when compared to a reference (adherent) cell type on the same substrate. As described in Reyes and Garcia (2003), it is recommended that the 50 % point be used for either ligand concentration or RCF for the most robust measurement of adhesion strength. The adhesion may vary due to changes in the phenotype of the cells or as a result of the specific properties of the surface. The substrate may include tissue culture-treated polystyrene, biomaterials, or bioactive surfaces. If the substrate is a hydrogel, care must be taken to avoid cohesive failure in the hydrogel (that is, detached cells have pulled away fragments of gel). The coating may consist of (but is not limited to) the following: natural or synthetic biomaterials, hydrogels, components of extracellular matrix (ECM), ligands, adhesion or bioactive molecules, genes, or gene products. Cell concentration is also critical, as use of too high a concentration of cells may result in cells detaching as a sheet, rather than as individual cells. This centrifugation approach, once validated, may be applicable for quality control (QC) and product development. However, until the method is correlated to other measures of cell attachment, the current method should be run in parallel with other known measures of cell adhesion.4.2 This practice does not cover methods to quantitate changes in gene expression, or changes in biomarkers, as identified by immunostaining. This practice additionally does not cover quantitative image analysis techniques. In some cases, the change in adhesive properties may reflect on the degree of differentiation or de-differentiation of the cells. However, it is worth noting that adhesive interactions do not necessarily reflect the differentiation state of a particular cell type, although in many instances they do. (See X1.3 for application to the adhesion of chondrocytes.)1.1 This practice covers a centrifugation cell adhesion assay that can be used to detect changes in adhesive characteristics of cells with passage or treatments. This approach measures the force required to detach cells from a substrate. Adhesion, among many variables, may vary due to changes in the phenotype of the cells.1.2 This practice does not cover methods to verify the uniformity of coating of surfaces, nor does it cover methods for characterizing surfaces.1.3 The cells may include adult, progenitor, or stem cells from any species. The types of cells may include chondrocytes, fibroblasts, osteoblast, islet cells, or other relevant adherent cell types.1.4 This practice does not cover methods for isolating or harvesting of cells. This practice does not cover methods to quantitate changes in gene expression, or changes in biomarker type or concentration, as identified by immunostaining. Nor does this practice cover quantitative image analysis techniques.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 Cell Therapy Products may be used to treat clinical conditions, for example in regenerative medicine (e.g. type I diabetes, acute myocardial infarction, pediatric congenital heart disease, chronic ischemic heart failure, cancer, Crohn’s disease, chronic wound repair, nerve and spinal cord injury, musculoskeletal repair), and may be used for immunotherapy (e.g. graft versus host disease, CAR-T therapy).5.2 Autologous, allogeneic, and xenogeneic cells may be used to make a product.5.3 A product may be cells only, cells combined with an inert carrier, cells within an extracellular matrix, or cells within a synthetic scaffold, and will include tissue engineered medical products containing cells.5.4 Cells may be gene-modified cells.5.5 Cells may be adult or embryonic stem cells.5.6 Cells may be minimally manipulated.1.1 This guide is intended as a resource for individuals and organizations involved in the development, production, delivery, and regulation of cellular therapy products (CTPs) including genetically modified cells, tissue engineered medical products (TEMPs) and combination products where cell activity is a functional component of the final product.1.2 This Guide was developed to include input derived from several previously published guidance documents and standards (section 2.4). It is the intent of this Guide is to reflect the current perspectives for CTP potency assays.1.3 CTPs can provide therapy by localized or systemic treatment of a disease or pathology.1.4 The products may provide a relatively short therapy, may be transient, or may be permanent and provide long-term therapy.1.5 The products may be cells alone, cells combined with a carrier that is transient, or cells combined with a scaffold or other components that function in the overall therapy.1.6 Potency assays may be in-vitro or in-vivo assays designed to determine the potency of a specific product. In-vivo assays are likely to be particularly useful to study the mechanism of action (MOA) of the therapy, but may not be desirable for final product quality control where they may be time-consuming and expensive, and where in-vitro assays may be preferable.1.7 It is likely that multiple assays, and possibly both in-vitro and in-vivo assays, will be required to provide a broad measure of potency. However, in-vitro assays are likely to be preferred as release assays for products, and so studies to identify potency assays should emphasize in-vitro assays that are correlative or predictive of preclinical or clinical results.1.8 Potency assays should be developed during the product development cycle and therefore are likely to be more comprehensive at the end of that cycle compared to the beginning of product development and testing. It is recommended that potency assays be developed as early as possible in the product development cycle (Figs. 1 and 2).FIG. 1 Progressive Implementation of Potency AssaysFIG. 2 Flow Chart for Stages in Product Development Showing When Potency Assays Will Be Developed and Introduced1.9 Potency measurements are used as part of the testing for cell and cell-based products to demonstrate that product lots meet defined specifications when released for clinical use.1.10 Shelf life specifications should be developed during the product development process to include potency measurements.1.11 This standard guide is not intended to apply to drug or gene therapy products. However, genetically modified cell therapies, for example the chimeric antigen receptor-T (CAR-T) cell therapy, which the United States FDA classifies as gene therapy, are applicable.1.12 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.13 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 The objective of this document is to provide guidance in the production, characterization, testing, and standardization of: (1) polymerizable collagen starting materials; and (2) collagen polymeric materials produced with polymerizable collagen formulations, used for surgical implants, substrates for TEMPs, vehicles for therapeutic cells and molecules, and 3D in-vitro tissue systems for basic research, drug development, and toxicity testing. This guide can be used as an aid in the selection, characterization, and standardization of the appropriate polymerizable collagen starting formulations as well as collagen polymeric materials prepared from polymerizable collagens for a specific use. Not all tests or parameters are applicable to all uses of collagen and users are expected to select and justify a subset of the tests for characterization purposes.4.2 This guide can be used by the following types of users:4.2.1 Manufacturers of polymerizable collagens and collagen polymeric materials who wish to set specifications for their products or provide characterization data for customers or users. They may also use the terminology and characterization sections to specify and differentiate the properties of polymerizable collagens and collagen polymeric materials.4.2.2 Producers of collagen polymeric materials that use polymerizable collagen as starting materials. Producers may use this guide to evaluate and characterize multiple sources of polymerizable collagen. They may also use this guide to assist with evaluation and comparison of single or multiple sources of polymerizable collagen and collagen polymeric materials.4.2.3 Researchers may use this guide as a reference for properties and test methods that can be used to reproducibly evaluate polymerizable collagens and collagen polymeric materials.4.3 The collagen covered by this guide may be used in a broad range of applications, forms, or medical products, for example (but not limited to) wound and hemostatic dressings, surgical implants or injectables (including in-situ forming), hybrid medical devices, TEMPs, injectable (including in-situ forming) or implantable delivery vehicles for therapeutic cells, molecules, and drugs, and 3D in-vitro tissue systems or models for basic research, drug development, and toxicity testing. The practical application of polymerizable collagens and collagen polymeric materials should be based, among other factors, on biocompatibility, application-specific performance measures, as well as chemical, physical, and biological test data. Recommendations in this guide should not be interpreted as a guarantee of success for any specific research or medical application.4.4 The following general areas should be considered when determining if the collagen supplied satisfies requirements for use in the above mentioned medical and research applications: source of polymerizable collagen, impurities profile, and comprehensive chemical, physical, and biological characterization and testing.4.5 The following documents or other relevant guidance documents from appropriate regulatory bodies relating to the production, regulation, and regulatory approval of devices, biologics, drugs, and combination products should be considered when determining if the collagen supplied satisfies requirements for use in medical and research products, including TEMPs, therapeutic delivery vehicles, and 3D in-vitro tissue systems:FDA CFR:21 CFR 3: Product Jurisdiction:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=321 CFR 58: Good Laboratory Practice for Nonclinical Laboratory Studies:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=58 FDA/CDRH CFR and Guidances:21 CFR Part 803: Medical Device Reporting:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=80321 CFR 812: Investigational Device Exemptions:    http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=81221 CFR 814: Premarket Approval of Medical Devices:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=81421 CFR 820: Quality System Regulation:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=820Design Control Guidance for Medical Device Manufacturers:   http://www.fda.gov/cdrh/comp/designgd.pdfPreproduction Quality Assurance Planning Recommendations for Medical Device Manufacturers (FDA 90-4236):   http://www.fda.gov/cdrh/manual/appende.htmlThe Review and Inspection of Premarket Approval Applications under the Bioresearch Monitoring Program—Draft Guidance for Industry and FDA Staff:   http://www.fda.gov/cdrh/comp/guidance/1602.pdf FDA/CDRH Search Engines:CDRH Guidance Search Engine:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfggp/   search.cfmCDRH Premarket Approval (PMA) Search Engine:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPMA/   pma.cfmCDRH 510(k) Search Engine:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPMN/   pmn.cfmCDRH Recognized STANDARDS Search Engine:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfStandards/   search.cfm FDA/CBER CFR and Guidances:21 CFR 312: Investigational New Drug Application:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=31221 CFR 314: Applications for FDA Approval to Market a New Drug:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=3121 CFR 610: General Biological Products Standards:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=61021 CFR 1271: Human Cells, Tissues and Cellular and Tissue-Based Products:   http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/    CFRSearch.cfm?CFRPart=1271Cellular & Gene Therapy Guidances and Other Publications:   http://www.fda.gov/cber/genetherapy/gtpubs.htmHuman Tissue Guidances and Other Publications:   http://www.fda.gov/cber/tissue/docs.htmCBER Product Approval Information:   http://www.fda.gov/cber/efoi/approve.htm21 CFR 600, 601 BLA Regulations:   http://www.access.gpo.gov/nara/cfr/waisidx_07/21cfrv7_07.html21 CFR 210, 211 GMP Regulations:   http://www.access.gpo.gov/nara/cfr/waisidx_07/21cfr210_07.html1.1 This guide is intended to provide characteristics, properties, test methods, and standardization approaches for evaluation and identification of specific polymerizable collagen formulations and collagen polymeric materials produced with these formulations.1.2 This guide focuses on characterization of purified polymerizable forms of type I collagen, which is the most abundant collagen in mammalian connective tissues and organs, including skin, bone, tendon, and blood vessels. Polymerizable type I collagen may be derived from a variety of sources including, but not limited to, animal or cadaveric tissues, cell culture, recombinant cell culture, and chemical synthesis.1.2.1 This guide covers evaluation of polymerizable collagens and collagen polymeric materials prepared from polymerizable collagens for use as a starting material for wound and hemostatic dressings, surgical implants, substrates for tissue-engineered medical products (TEMPs), delivery vehicles for therapeutic cells or molecules, and 3D in-vitro tissue systems for basic research, diagnostics, drug development, and toxicity testing. Most collagen products on the market today are regulated as devices since their primary intended purpose is not achieved through chemical action within or on the body. However, a medical product comprising polymerizable collagens or collagen polymeric materials may be regulated as a device, biologic, drug, or combination product depending on its intended use and primary mode of action.1.2.2 Polymerizable collagen or collagen self-assembly implies that the collagen composition exhibits spontaneous macromolecular assembly from its components without the addition of exogenous factors such as cross-linking agents. Polymerizable collagens may include but are not limited to: (1) tissue-derived monomeric collagens, including tropocollagen or atelocollagen, and oligomeric collagens; (2) collagen proteins and peptides produced through in vitro cell culture, with or without using recombinant technology; and (3) chemically synthesized collagen mimetic peptides. It should be noted that the format of collagen polymeric material products also will vary and may include injectable solutions that polymerize in situ as well as preformed sheets, particles, spheres, fibers, sponges, matrices/gels, coatings, films, and other forms.1.2.3 This guide may serve as a template for characterization and standardization of type I fibrillar collagen or other collagen types that demonstrate polymerization or self-assembly.1.3 This guide does not provide a significant basis for assessing the biological safety (biocompatibility) of polymerizable collagens and collagen polymeric materials. While the ability of collagen polymeric materials to guide cellular responses through provision of cellular adhesion and proteolytic domains as well as physical constraints (for example, structural, cell-matrix traction force) has been well documented through extensive clinical and basic research studies (1-5),2 users are directed to the ISO 10993 series for evaluating biological risks of medical devices. The biocompatibility and appropriateness of use for a specific application is the responsibility of the product manufacturer.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 The following precautionary caveat pertains only to the test method portion, Sections 6 and 7, of this guide: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 A large number of industrial processes involve transfer and feeding of bulk solids, and the ability of such materials to flow in a controlled manner during these operations is critical to product quality.5.2 Direct shear cells are among the most important methods for measuring the flow properties of bulk solids in industrial applications for bulk solids handling.5.3 Direct shear cells have many advantages over simpler methods of measuring bulk solids flow properties, but their operation is more complex and the procedures for their use must be carefully controlled to produce accurate and reproducible data.5.4 The three most popular direct shear cell types are: Translational (D6128), Annular (D6773), and Rotational (D6682 and D7891).5.5 From shear cell data, a wide variety of parameters can be obtained, including the yield locus representing the shear stress to normal stress relationship at incipient flow, angle of internal friction, unconfined yield strength, cohesion, and a variety of related parameters such as the flow function.5.6 In addition, these three direct shear cells can be set up with wall coupons to measure wall friction.5.7 When the shear cell data are combined with unconfined yield strength, wall friction data, and bulk density data, they can be used for bin and hopper evaluation and design.1.1 This guide covers theory and principles for obtaining reliable and accurate bulk solids flow data using a direct shear cell. It includes characteristics and limitations of the three most popular direct shear cell types: Translational (D6128), Annular (D6773), and Rotational (D6682 and D7891).1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measure are included in this standard.1.3 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.1.4 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 This test method is useful for assessing the cytotoxic potential of new materials and formulations and as part of a quality control program for established medical devices and components.4.2 This test method assumes that assessment of cytotoxicity provides useful information to aid in predicting the potential clinical applications in humans. Cell culture methods have shown good correlation with animal assays and are frequently more sensitive to cytotoxic agents.4.3 This cell culture test method is suitable for incorporation into specifications and standards for materials to be used in the construction of medical devices that are to be implanted into the human body or placed in contact with tissue fluids or blood on a long-term basis.4.4 Some biomaterials with a history of safe clinical use in medical devices are cytotoxic. This test method does not imply that all biomaterials must pass this assay to be considered safe for clinical use (Practice F748).1.1 This test method is appropriate for materials in a variety of shapes and for materials that are not necessarily sterile. This test method would be appropriate in situations in which the amount of material is limited. For example, small devices or powders could be placed on the agar and the presence of a zone of inhibition of cell growth could be examined.1.1.1 This test method is not appropriate for leachables that do not diffuse through agar or agarose.1.1.2 While the agar layer can act as a cushion to protect the cells from the specimen, there may be materials that are sufficiently heavy to compress the agar and prevent diffusion or to cause mechanical damage to the cells. This test method would not be appropriate for these materials.1.2 The L-929 cell line was chosen because it has a significant history of use in assays of this type. This is not intended to imply that its use is preferred, only that the L-929 is an established cell line, well characterized and readily available, that has demonstrated reproducible results in several laboratories.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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